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Đặc điểm dịch tễ học, đột biến gen bệnh thalassemia ở phụ nữ người dân tộc tày và thử nghiệm giải pháp can thiệp tại 6 xã, huyện định hóa, tỉnh thái nguyên tt tiếng anh

MINISTRY OF EDUCATION AND TRAINING
THAI NGUYEN UNIVERSITY

NGUYEN KIEU GIANG

EPIDEMIOLOGICAL AND MUTATION GENE OF THALASSEMIA
IN TAY WOMEN AND INTERVENTION SOLUTIONS AT 6
COMMUNITIES, DINH HOA DISTRICT, THAI NGUYEN PROVINCE

Specialization: Social Hygiene and Health Organization
Code: 62 72 01 64


THAI NGUYEN - 2019


MINISTRY OF EDUCATION AND TRAINING
THAI NGUYEN UNIVERSITY

NGUYEN KIEU GIANG


EPIDEMIOLOGICAL AND GENE OF THALASSEMIA IN TAY
WOMEN AND INTERVENTION SOLUTIONS AT 6 COMMUNITIES,
DINH HOA DISTRICT, THAI NGUYEN PROVINCE

Specialization: Social Hygiene and Health Organization
Code: 62 72 01 64


Science instructor 1:

Associate Professor Nguyen Tien

Dung
Science instructor 2:

Professor Hoang Khai Lap

THAI NGUYEN - 2019


1
INTRODUCTION TO DOCTORAL THESIS
1. Necessity of the thesis
Thalassemia is a haemolytic anemia that is inherited due to abnormalities in the synthesis of
hemoglobin resulting in anemia at different levels. According to the World Health Organization
(WHO), about 7% of the world's population carries the Thalassemia gene, with between 300,000
and 400,000 newborns with severe hemolytic anemia.
In Vietnam, according to incomplete statistics, more than 12 million people are carrying the
gene for thalassemia common in all provinces nationwide. In particular, the proportion of people
carrying the thalassemia gene in ethnic minority groups is higher than the Kinh majority. With 53
ethnic groups with genotypes, the frequency of mutant genes may vary among ethnic groups, the
study of the frequency of gene transfer in each ethnic group is essential for the development of the
thalassemia prophylaxis program. in Viet Nam. Among ethnic minorities in Vietnam, the Tay ethnic
group has a population of more than 1.6 million, topping the top 10 ethnic groups in the country.
The rate of 13.2% carrying the thalassemia gene in the Tay group migrated to the south was
reported in 2010. However, the frequency of gene transfer, mutant genotype and frequency of
alleles in the East group in East North has not been fully reported.
Thai Nguyen is a province in the midland and mountainous area of the North East, inhabited
by a number of ethnic minority groups, of which the highest proportion is the Tay ethnic group.
However, there is no consistent data on the incidence of disease genes and mutant genotypes, as
these are very useful information for thalassemia prevention in the region. In addition, the
development and testing of a preventive screening program - counseling at the grassroots level is
rarely studied in Vietnam.
2. Objectives
1. Identification of some epidemiological and moleculer epidemiological characteristics of
thalassemia in Tay ethnic minority women in the reproductive age in Dinh Hoa district, Thai Nguyen
province in 2015.
2. Experiment and evaluate the effectiveness of thalassemia screening, monitoring and
counseling in Dinh Hoa district primary health care.
3. Practical signification and new contributions of the thesis
New contributions to science
Application of molecular biology assay to analyze the rate of hemoglobin in determining the
frequency of carrying thalassemia gene among Tay ethnic group in Thai Nguyen area. The 27% carrying
gene thalassemia has never been reported in previous studies in this population. In particular, the
frequency of carrying alpha thalassemia gene was reported in the Tay group at the site of study at
16.3%.
Successfully developed and applied screening, counseling and prenatal diagnosis in
thalassemia prophylaxis at communi health station. Screening and counseling provided directly by
the health staff of communi. The process of transporting and receiving blood samples closely, the
implementation of disease diagnosis, genotypic diagnosis at the provincial level has solved the
problem of access and availability of the health system.
Contribute to the reality
The identification of mutant genotypes and the frequency of alleles in the Tay population at
the study sites were significant in the prevention of thalassemia. This information will be used to
develop a thalassemia diagnostic panel for the Northeastern region in general, to estimate the
incidence of new heavy organisms in the population and to contribute data to the development of
the genetic map. thalassemia in Vietnam.


2
The intervention model for thalassemia is feasible with a contingency cost estimate of ~ 1%
for a new case compared to the cost of treating patients with new thalassemia major.
The study has transferred the OF screening technique to Dinh Hoa district health center,
transfer. Transfer of thalassemia screening and counseling model for Dinh Hoa district. Transfer of
HbE screening technique to Thai Nguyen Blood Transfusion Center
4. The structure of the thesis
The thesis is presented in 121 pages, including: back ground (2 pages), overview (40 pages),
subjects and research methods (17 pages), research results (23 pages), discussion (35 pages),
conclusions (2 pages), recommendations (1 pages).
The thesis consists of 37 table, 22 picture. In the references 105, 80 documents in English, 25
documents in Vietnamese, 42 documents published in the last 5 years (70 documents published in
the last 10 years). The appendix includes the data collection tools, the sample list and the
intervention images of the research team.
CHAPTER I. LITERATURE OVERVIEW
1.1
The concept of thalassemia
The term "thalassemia" or "haemolytic haemorrhage" refers to a group of pathological
conditions characterized by a reduction in the synthesis of one of the two globin chains (α or β) that
constitutes the normal human hemoglobin molecule (HbA, α2β2), resulting in a reduction in the
hemoglobin synthesis in the endothelium, which is manifested externally by anemia.
1.2
Genetic mechanism of thalassemia
According to the inheritance characteristics of chromosomal recesses and the status of
disease in the previous life, there are five cases of hereditary diseases to the next.
In cases where both parents have homozygous disease, 100% of cases are homozygous. In
case of a homozygous, a heterozygote: 50% of children with homozygotes, 50% of children with
heterozygote. In cases both perents have heterozygous: 50% of heterozygous children, 25% of
normal children, 25% of homozygouts. In case of an ordinary person, a heterozygote: 50% of
children with heterozygosity, 50% of normal children. In case of an ordinary person, a homosexual:
100% of children have heterozygous disease.
1.3
Some epidemiological problems of thalassemia
Characteristics of age groups: The different forms of disease manifested and affected in age
groups are different. Depending on age and other clinical characteristics, the physician may
preliminarily diagnose the condition so that a proper diagnosis is identified for the diagnosis. Age,
gender is also one of the criteria to consider when developing a thalassemia screening program
Ethnic characteristics: Many studies in the world claim that ethnic minority groups tend to
carry genes much higher than that of majority ethnic groups. This is explained by the epidemiological
and cultural characteristics of ethnic minority groups. Ethnic minorities also tend to communicate
with the same locality and with the language group, which involves geographic proximity. This is one
of the factors that increase the rate of thalassemia gene in ethnic minority communities.
Gender: Gender is considered in the context of anemia and the complications of anemia
caused by thalassemia. Both male and female clinical conditions are affected by anemia and similar
complications. However, due to the specificity of pregnancy only in women, pregnant women with
thalassemia have many health risks, risk during birth as well as postpartum complications.


3
Migration: Thalassemia is the first known disease in the Mediterranean, where it is described as
prevalent in epidemic-endemic countries such as North Africa, the Middle East, India, South China and
Southeast Asia, however, today the disease is reported in most countries and regions around the world.
Studies indicate that inter-territorial migration is the cause of widespread and diversified genomes
worldwide.
Inbreeding: Inbreeding is the marriage between people who have blood relations, usually
between cousins or sometimes uncles and nieces. Inbreeding leads to inbreeding, which increases the
likelihood of two people carrying the same gene to marry, and increases the likelihood of thalassemia
homozygosity in the offspring.
Estimating the incidence of newborn infants in the population: Hardy-Weinberg's law is used
to calculate the number of children born with thalassemia in 1,000 live births. The frequency of genotypes,
estimated by the Hardy-Weinberg formula, is as follows: The frequency of genes is constant over
generations and allele frequencies in the latter are always proportional to p2: 2pq: q2. . The condition of
this argument is: (1) no mutation occurs resulting in new allele; (2) all individuals have the same
opportunity in marriage and reproduction; (3) no significant immigration from other fully populated
populations.
1.4
Studies on the epidemiology and molecularities of thalssemia
1.4.1 In the World
According to the World Health Organization (WHO), about 7% of the world's population
carries the Thalassemia gene, with between 300,000 and 400,000 newborns with severe hemolytic
anemia.

Figure 1. 1. Map of alpha and beta thalassemia mutations in the world
1.4.2 In Viet Nam
Tablet 1. 1. The contribution carriers thalassemia gene in Viet Nam
Local -Ethnic

Sampl
es

Rat
e(%)

Author


4
Kinh (Hue)

1100

5,6

Phan

Le

Minh

Tuan

(2014)
Kinh (An Giang)

1572

19,

Pham Ngoc Dung (2011)

19,

Phan Thi Thuy Hoa (2010)

7,0
12,

O'Riordan, S (2010)

8
Kinh (Quang Binh)

130
3

Kinh (Khanh Hoa)
Tay, Dao (Thai Nguyen)
Muong (Hoa Biinh)
C’Tu, Ta Oi (Hue)

452
712

Vu Thi Bich Van (2010)

2
22,

Duong Ba Truc (2010)

6

54

42,

Nguyen Van Hoa (2013)

15,

Phan

Le

Minh

Tuan

Phan

Le

Minh

Tuan

6
Ta Oi (Hue)

1100
4

C’Tu (Hue)

1100

(2014)
11,

1
S’Tieng
E de
M’Nong

3917
266
551

(2014)
63,

9
32,
2

O'Riordan, S (2010)
(Khanh Hoa, Binh Phuoc)

24,

2
1.5
The screening and diagnostic tests of thalassemia
1.5.1 The screening tests of thalassemia
Screening of thalassemia by OF test
Screening of HbE by DCIP
Screening of thalassemia by CBC test – MCV, MCH
1.5.2 The diagnostic tests of thalassemia
Diagnostic the types of thalassemia by analysis the rate of hemoglobin typing
Diagnostic the thalassemia mutation gene by moleculer analysis
1.6
Prevention of thalassemia
Currently, there are three cases of thalassemia that are listed as preventive measures:
• homozygous beta thalassemia, or Cooley disease
• Thalassemia / HbE (beta 0 thalassemia - HbE)
• Homozygous alpha 0 thalassemia, or Bart's Hydrops Fetalis.
1.6.1 Approach to develop a thalassemia prophylaxis program
Thalassemia affects three groups of people in the community: common people, people with
thalassemia, people with thalassemia. Prophylactic treatment with thalassemia should have a
comprehensive impact on these groups to prevent the risk in these groups at the time of marriage.
After marriage and pregnancy, the diagnosis of fetal disease (CTS, pre-embryo transfer diagnosis ...)
is the last resort to be prevented.


5
The approach to prevention for each target group is different. With the community in mind, when it
is not yet known whether individual carriers carry genes, the first step is to test the gene carrying the
gene. There are many screening stages: screening through cord blood storage. Film screening at school
age, college students. Humanitarian Blood Screening Clinic Periodic health screening. Check the
subject of marriage registration. Screening pregnant women in the early months ...
1.6.2 Thalassemia Prevention Programs in the World.
Screening program for pregnant women.
Pre-Marriage Screening Program.
Other thalassemia prophylaxis programs
1.6.3 Research on screening and prenatal screening in Vietnam
Vietnam has no national thalassemia prophylaxis program, thalassemia interventions are
mainly focused on screening models, TSH. A small number of authors propose interventions based
on CT scans in community hospitals or community-based IEC.

(A)Figure 1. 2. Thalassemia screening procedures (B)Screening, counseling, prenatal diagnosis at
at An Giang Hospital
Tu Du Hospital, Ho Chi Minh City.
CHAPTER II. SUBJECT AND METHODODOLOGY
2.

2.1
Research subjects
2.1.1 Descriptive study
Tay woman from 15-49 years old, marrieriedried and have 1 child; Communes health workers
intervene.
2.1.2 Interventional studies
(1) Health workers in 24 communes and Cho Chu town, Dinh Hoa district, Thai Nguyen province.
(2) Pregnant women under 12 weeks of age registered for management of pregnancy at the commune
health stations. (3) Husbands of pregnant women under 12 weeks of age who are registered for
management of pregnancy at the commune health stations who are positive for OF screening.
2.1.3 Location and time of study
2.1.3.1 Study location: Dinh Hoa district, Thai Nguyen province
2.1.3.2Time of the study: June 2015 to June 2017 and divided into two phases. (1) Cross-sectional (2)
Interventions (Figure 2.2)


6

Figure 2. 1. Time of the study
2.1.4 Methodology
2.1.4.1 Research design

Design of the cross sectional (Phase I)
Design of Interventional studies (Phase 2)
2.1.4.2 Calculation of sample size, sample selection
Use the method of calculating sample size for population and random sampling for crosssectional studies. 300 Tay women were selected for descriptive study. With intervention research on
basic health staff, sample size and method of target selection, convenience. 12 health workers in 6
communes of Dinh Hoa district were allocated to the intervention group. 36 health workers in the
remaining 18 communes were allocated to the control group.
2.1.4.3 Research indicators
Group of epidemiological indicators: age, sex, occupation, near-geographical marriage, inblood marriage, economic.
Hematological indexes: RBC, Hb, HCT, MCV, MCH,
Group screening tests: OF, DCIP
Group of indicators K.A.P: point and classify knowledge, attitude, practice.
Indicators of communication: Number of consultations, number of consultations, number of
counseling materials distributed, number of couples agreeing with counseling
2.1.4.4 Research content
Descriptive study: To determine the proportion of thalassemia carriers gene, genotype, and
frequency of alleles. Tay minority ethnic women aged 15-49 in Dinh Hoa, Thai Nguyen were selected
for the study. Subjects were interviewed using a questionnaire that was available to collect


7
epidemiological information. The intravenous infusion of blood is also collected and sent to Thai
Nguyen Hematology and Blood transfution Center for screening, complete blood cell and
hemoglobin electrophoresis. 0.5 ml of each blood samples was separated into a new tube for DNA
analysis of thalassemia gene mutations.
Intervention study: The intervention process is divided into 3 phases.
Phase 1: pre-intervention investigation; Determining the status of health workers in K.A.P, indepth interviews with health leaders to identify the need for disease prevention, possible challenges
when implementing the intervention and plan to overcome.
Phase 2: Setting up a Steering Committee for interventions for thalassemia prevention and
training for commune health staff; Training of commune health workers with the following contents:
Add, update knowledge about thalassemia
Definition, classification of thalassemia
Epidemiology of carrier genes in Vietnam
Symptoms, diagnosis, treatment thalassemia
Prevention of thalassemia
Training on testing and screening procedures in Dinh Hoa district.
Training on the technique of screening for carriers of thalassemia gene in clinics using OF test.
Training on improving genetic counseling skills in congenital haemorrhagic fever:
Laboratory counseling: screening, diagnostic tests; Laboratory tests; Interpretation of test
results; The medical facility may carry out tests; Cost of testing.
Genetic counseling with test results at specific stages of screening.
Consultation on termination of pregnancy with the following contents: Indications, methods of
implementation, accidents, legal procedures, medical facilities can be implemented, costs.
Phase 3: Thalassemia screening for pregnant women <12 weeks at the clinic and monitoring
and counseling for health workers (Figure 2.2).

Figure 2. 2. Thalassemia screening and counseling strategies
Thalassemia screening for pregnant women by the OF test was performed at commune
health stations in combination with prenatal management program. Pregnant women under 12
weeks of age who are registered for pregnancy management at the commune health stations will be
informed about thalassemia and will be invited to participate in the screening program. Subjects
agreed to screen will be tested at the right at the station and counseling test results immediately


8
after the test results. Researchers will review and evaluate the screening process and counseling of
health workers, which will provide necessary technical support and support to health workers.
Blood samples of couples at risk after screening will be transferred to Blood Transfusion
Center - Thai Nguyen National Hospital (Province level) to carry out diagnostic tests for genetic
status of couples and risk identification. muscle for fetus. Fetuses who are at risk for thalassemia
major will be advised to make a diagnosis to determine the disease of the fetus.
The prenatal diagnosis of fetus (identified as risk) will be performed at the Center for Applied
Medical Research in Medicine and Pharmacy - Hanoi Military Medical Academy (National level). Pregnancy
cure is advised for the fetus is diagnosed with severe disease after the results of the prenatal diagnosis of
fetus.
All results of the tests (after screening) are sent to the commune health staff. All counseling
activities were conducted by trained health staff in intervention communes.
The consultative process used in stage 3 (Figure 2.2).
2.1.4.5 Diagnostic criteria for thalassemia, index of red blood cells and K.A.P
Diagnostic criteria carrying the thalassemia gene
Beta thalassemia gene: Electrophoresis Hb with HbA2> 3.5% and / or HbF> 2%. DNA tests
detect mutations in the beta globin gene.
Alpha thalassemia gene: Electrophysiologic Hb findings of abnormal hemoglobin mutations in
alpha globin genes: HbCS, HbH, HbPs. DNA tests detect mutations in the alpha globin gene.
Normal index type Red Blood Cells
- Classification of anemia: Hb <120 g / l
- Small red blood cells: MCV <80fl
- Hypochromic: MCH <27pg and / or MCHC <300g / l
Classification K.A.P
There are 18 knowledge questions with 33 correct answers. Each correct answer is 1 point,
wrong answer or do not know 0 points. The maximum score for the section is 33 points and is
assessed at two levels of achievement when the score is ≥ 50% of the total score (≥16.5 points). Not
achieved when the knowledge score <16.5 points.
There are 11 questions related to the views of commune health workers in the prevention of
thalassemia. Each question was assessed on a Likert scale (1 - Strongly agree, 2 - Agreed, 3 - Not
clear, 4 - Disagree, 5 - Strongly disagree). Each answer with the correct point is a point, the point is
not true or not clear 0 points. The maximum score for the part of the attitude was 11 points and was
assessed at 2 levels: achieves when the knowledge score was ≥50% of the total score (≥5.5 points),
Not achieved when the knowledge score was <5.5 points .
Evaluate Thalassemia Prevention with practical evaluation questions. The maximum point for
practical questions is 27 points and is evaluated at two levels. achieves when practicum point ≥ 50% of
maximum score (≥13.5 points), Not achieved when knowledge score <13.5 points.
2.1.5 Data processing methods
- Percentage is used to describe classifiers, hierarchies.
- Mean and standard deviations are used to describe continuous variables.
- Use statistical test χ2 (When squared) with significance level p <0.05 to:
+ Investigate the difference in the rate of thalassemia gene according to epidemiological indicators.
+ Difference in K.A.P criteria between control group and intervention group.
- Use the McNemar's statistic test to compare K.A.P changes before and after intervention on
the same group of health workers.


9
CHAPTER III. THE RESULTS
3.1. Epidemiological characteristics, characteristics of the thalassemia gene of the study
subjects and the value of screening tests in the community
Tablle 3.1. Epidemiological characteristics of study subjects (n = 300)
General information
Numbers
Rate (%)
Age
From 15 to 24 years old
82
27.3
From 25 to 34 years old
181
60.4
From 35 to 44 years old
36
12.0
From 45 to 49 years old
1
0.3
Education
Can read and write
2
0,7
Primary school
20
6,7
Secondary school
138
46,0
High School
84
28,0
College, University
56
18,6
Job
Farming
202
67,3
Officials
74
24,7
Other occupations
24
8,0
Economy
Poor
76
25,3
Near poor
135
45,0
Not poor
89
29,7
Immigration status before marriage
Same district, different commune
114
38,0
Same district, same commune
150
50,0
Other district.
36
12,0
Marriages inbreeding
Are not
291
97,0
Yes, in addition to 3 generations
8
2,7
Yes, for 3 generations
1
0,3
Comment: 27.3% of respondents aged 15 to 24 years old, 60.4% of respondents were in the 25 to 34 age group, 35
years and over were 12.3%. The majority of mothers with lower secondary education (92.6%), 7.4% have primary or
lower education. The percentage of mothers with farming occupations is 67.3%, followed by civil servants (24.7%) and
other occupations (8%). The rate of poor households is 25.3%, near poor 45.0%, the remaining is non-poor households
29.7%. The majority of married women in the same district (88%), including 38% in the commune, 50% in other
communes. 12% of married women in other districts. There are 9 cases of inbreeding in which 1 case of marriage in 3
generations.
Table 3. 5. Anemia classification of subjects studied
Erythrocyte morphology

Microcytic

Nomal

Total

and / or
Anemia classification
Major anemia

hypochromic
n
%
1
1

n
0

%
0

n
1

00
Moderate anemia

3

%
0
,3

1

0

0

3

1


10
2
Minor anemia *

00
3

2
No anemia

6
5,3

3
3

Total

2
7
1

5,1
9

1
4,7
1
85

3

3

4
9

8
4,9

2

0,7
6,3
2

18
6

1
7
2,7

3

1

8
2,7
02
7,3
00
00
Comment: 100% red blood cells of patients with moderate to major anemias are microcytic and

hypochromic. With minor anemia is 65%
Table 3.6. Frequency of carrying thalassemia gene at the study site
Characteristics
Carrying thalassemia gene
Not carrying thalassemia gene
Total

Number
81
219
300

Frequency
27,0
73,0
100


11
Comment: Frequency of carrying thalassemia gene at the study site is 27%.
Table 3.7. Thalassemia gene carrier classification
Classification

N
umber

α thalassemia

Rate (%)
In 81* person carrier

In 300 Tay

4

gene
60,4

woman
16,3

2

27,2

7,3

5
5

6,2
6,2

1,7
1,7

8

100

27,0

9
β thalassemia
2
Hemoglobin E
Combinal α/β
thalasssemia
Total
1


12
* The persons carrying thalassemia gene are diagnostic by electrophoresis and PCR test

Comment: In the 300 Tay woman, the rate carrier thalassemia gene is 27%: α thalassemia 16,3%, β
thalassemia 7,3 %, HbE & α – β thalassemia 1,7%. In the numbers carrying thalassemia gene, alpha
thalassemia is 66,6% (60,4% heterozygote, 6,2% heterozygote combinal α/β).
Table 3.8. Distribution of phenotype and genotypes thalassemia
Genotypes Thalassemia

N
umber

In 300 Tay woman

Rate (%)
In 70* person carrier
gene

Heterozygote α0-thal
--SEA/αα

3

11,3

48,57

1

0,3

1,43

4
5

1,3
1,7

5,71
7,14

4
1

1,3
0,3

5,71
1,43

6
2
2

2,0
0,7
0,7

8,57
2,86
2,86

1

0,3

1,43

5

1,7

7,14

1
3

0,3
1,0

1,43
4,29

1
1

0,3
3,7

1,43
-

2

73,0

-

3

100

100

4
THAI

-- /αα
Heterozygote α+-thal
αα/-α3.7
αα/αCSα
Heterozygote combinal
α0-thal/ α+-thal
--SEA/-α3.7
--SEA/αCSα
Heterozygote β0-thal
β/β41/42
β/β17
β/β71/72
Heterozygote β+-thal
β/β-28
Heterozygote Hb E
β/β26
Heterozygote α0-thal
/Heterozygote β0-thal
--SEA/αα; β/β17
--SEA/αα; β/β41/42
Heterozygote α+-thal
/Heterozygote β0-thal
αα/-α3.7; β/β17
Unknown genotype
1
No mutation detected
19
Total
00

* 11 cases carrier gene unknown genotype mutant in the screening panel.
Comment: The 14 combined genotypes of eight mutant phenotypes were identified in 70 of
the identified thalassemia genes.


13
Table 3.9. Distribution gene mutant according hematology index
Num

Genotype
αα/α
α
-SEA

/αα
--

THAI

/αα
αα/-

α3.7
αα/α
CS

α
--

SEA

/-α3.7
--

SEA

/αCSα
αα/α

β/β

230

β/β

34

β/β

1

β/β

4

β/β

5

β/β

4

β/β

1

β/β41

αα/α

β/β17

α

β/β71

αα/α
/72

α
αα/α

β/β

αα/α

β/βE

α
-SEA

-SEA

/αα
αα/-

α3.7
Tota

2
2
1
5

41

/42

/αα

l

β/β

6

-

28

α

Hb,g/

MCV

A2A

L
128,6

,ft
88.4±

H, pg
28.8±

A2A

±9,6
114,3

6.82
66.7±

2.6
20.7±

±8,4

3.11

1.12

ber

/42

α

Hb typing

3

β/β17

1

β/β17

1

-

300

A2A

MC

116

69.5

21.1

129,5

83.2±

26.7±

A2A CS

±6,8
125,8

3.24
85.5±

1.23
27.4±

A2A Bart’s

±11,1
93,5±

4.1
57.5±

1.57
17.2±

3.28

1.36

A2A

H

5
A2A Bart’s

73

83.4

22.1

A2A

112±

63.9±

19.4±

A2A

3,3
105±

3
65.7±

0.94
20.7±

A2FA

2,8
114±

0.49
70.4±

0.49
22.1±

8,9

9.97

4.6

H CS

A2A
EA
A2FA
A2A
A2A
-

126

73.1

22.6

110,4

78.7±

25.1±

±12,6
114±

3.86
66.8±

1.46
21.2±

13,7

0.66

0.93

119

65.9

20.5

115

68.5

20.9

-

-

-

Comment: There are 5 cases of HbH due to the combination of heterozygous α0 and
heterozygous α + or HbCS. These types cause mild to moderate anemia. The types of heterozygous
α0, β0 all cause mild anemia, MCV and MCH indicators in these cases are lower than normal levels.


14
Table 3.10. Rate and classification of mutant alleles among surveyed alleles
Mutations allele type

T
ype

Mutation allele
α-Thalassemia

Number

Frequ
ency allele

Rate (%) in allele
mutations

91
α

-- SEA

0

α

-- THAI

0

α

-α3.7

+

α

-αCSα

+

43
1
9
6

0,072

47,3

0,002

1,1

0,015

9,9

0,010

6,6

0,015

9,9

0,007

4,4

0,003

2,2

0,002

1,1

0,008

5,5

0,018

12,1

β-Thalassemia
Cd 41/42 (-TTCT)

0

β

Cd 71/72 (+A)

0

β

Cd -28 (A->G)

+

β

Cd 26 (G->A)
has

identified mutations
Normal allele

0

β

Cd 17 (A->T)

Allele

β

E

not

β
T

β
A

9
4
2
1
5
11
509

0,848
Total
600
1,00
100
Comment: In the total number of Tay women carrying genes with 3 mutant alleles on HBA1
gene, it is defined as type - SEA, - THAI, -α3.7, 1 type of point mutation on HBA2 gene is -αCS. 5
mutant allele types in HBB gene including Cd 41/42 (-TTCT); Cd 17 (A-> T), Cd 71/72 (+ A), Cd
28 (A-> G), Cd 26 (G-> A) HbE. Regarding the frequency of single alleles, type --SEA has an
outstanding frequency accounting for 47.3%, followed by other mutations.


15
Table 3.11. Estimate the number of children with new thalassemia major at the study site
Genotype

Frequency
allele

n
4

α0

4

β0, β+

α0 Thal
β Thal
homozygous homozygous

0,0
73

1
6

βE

Frequency new thalassemia major

0,0
27

5

0,0
08

β Thal/ HbE

Estimated
/1000
babies
born lived

Estimated
/5000
babies
born lived

0,0054

-

-

5,4

27

-

0,0007

-

0,7

4

-

-

0,0002

0,2

1

Total
6,3
32
Comments: The frequenses of Hbbart is estimated to be 0.0054, corresponding to about

5/1000 babies was born lived or 27/5000 babies was born lived. With beta thalassemia, ~ 4/5000
babies was born lived, with beta thalassemia / HbE estimated ~ 1/5000 babies was born lived.
Table 3.12. Classification carriers of thalassemia gene by marital status
Carriers of
T

Marital status
Marria

otal

Are not
91
Yes, beyond 3 generations
Yes, within 3 generations
Same
district,
same

Immigr
ation
before
marriage

Rate

n

%

2

ges inbreeding

commune
status
Same

thalassemia gene

8
1
1
14

district,

different

commune
Other district

81
0
0

27,84
0,0
0,0

39

34.2

34

22,7

1
50
3

6
8
22,2
Comment: The carrier of the gene in the marriage group in the same commune accounted for
34.2%; other communes but the same district accounted for 22.7%, other districts 22.2%. None of
the subjects carried the gene among inbreeding.
Table 3.13. Classification carrying thalassemia gene according to anemia.
Total

Carriers thalassemia

Classification
Anemia
Major anemia
Moderate anemia
Mild anemia

gene
n
82
1
32
49

%
27,3
0,3
10,7
16,3

n
55/82
1/1
29/32
25/49

Rate
67,1
100,0
90,6
51,0


16
Not anemia
Tổng

218

72,7

300

100.0

26/21
8

11,9

81/30

27.0
0
Comment: The rate of people carrying the gene in anemia group is 90.6% on average; mild
anemia is 51%; no anemia is 11.9%. There is 1 case of carrying the gene with severe anemia.
Table 3.14. The value of test indicators in screening for thalassemia carriers
Indica
tor

Sensiti
ve

Specificit
y

Predicti

Predicti

ve value (+)

ve value (-)

(%)

(%)

(%)

(%)

MCV*

84,0

96,3

89,5

94,2

MCH**

92,6

89,5

76,5

97,0

OF

77,8

91,3

76,8

91,7

DCIP #

100

94,9

25%

100

A
UC
0
,901
0
,910
0
,846
0
,975

* MCV <80fL: Positive; MCV> = 80fL: Negative; ** MCH <27pg: Positive; MCH> = 27pg Negative; # DCIP values are evaluated in HbE screening

Comment: In the screening of thalassemia MCH has the highest sensitivity (92.6%) followed by MCV
(84.0%) and OF (77.8%). With the highest specificity, MCV (96.3%) followed by OF and MCH, the
rates were 91.3% and 89.5%, respectively. With HbE screening, DCIP test sensitivity and specificity
are 100% and 94.9%.
Table 3. 7. Results of combined screening for thalassemia and HbE carriers
Combined
test
OF/DCIP
MCV/DCI
P
MCH/DCI

Sensit
ive

Specif
icity

Predicti
ve value (+)(%)

Predicti
ve value (-)

(%)

(%)

(%)

85,19

87,76

71,88

94,12

91,36

92,69

82,22

96,67

95,06

85,84

71,30

97,92

A
UC
0
.864
0
.920
0

P
.904
Comment: MCV / DCIP combination has the best value in screening with AUC = 0.920.
2.2
Effectiveness interventions in community about thalassemia
2.2.1 Results of intervention activities
Established a steering committee to implement thalassemia prevention program in Dinh Hoa
district, Thai Nguyen province.
12 health workers in 6 intervention communes were trained to update thalassemia
prevention knowledge, and skills to conduct testing of thalassemia screening.


17
12 health workers / 6 intervention communes were directly involved in screening, directly
counseling thalassemia prophylaxis at the commune level in 1 year of intervention.
260 face-to-face interview sessions were conducted by commune health workers.
260 leaflets, communication materials issued to couples
72 supervision sessions, supporting 6 communes in 1 year.
100% of commune health workers intervened to perform thalassemia screening techniques
with the OF test after intervention.
100% of intervention commune health workers are able to provide genetic counseling based
on thalassemia screening test results after intervention.
2.2.2 Effectiveness of interventions for K.A.P thalassemia
Bảng 3. 18. General knowledge of thalassemia prophylaxis between intervention group and
control group.
General knowledge

Before

Achieve
n
1

Control

intervention

1

Not
%
3

0.56

Intervention

4

Total

1

Achieved
n
2
5
8

3

3

3.33
5
Affter

Control

intervention

1
3

Intervention

3
6.11

1
0

Total

3

8

2

8

3.89

3.33

3
6

1
6.67

4

4

6

2
2

,857

2

8.75

3

0

1

6

2

3
6

6
6.67

1.25

p

otal
%
6

9.44

3

T

0
,005

1
2

5

4

3
7.92
5
2.08
8
Comment: There was no difference in knowledge scores between control and intervention
groups at baseline (p> 0.05). After the intervention, knowledge gained in the intervention group was
83.3% higher in the control group (36.1%). This difference was statistically significant at p <0.05.
Bảng 3.19. Attitudes and attitudes in thalassemia prevention in control and intervention
groups.
General attitudes

Before

Achieve
n
1

Control

intervention

4
Intervention

Not
%
3

8.89
5

Achieved
n
2
2

4
1.67

Total

1

%
6

2

3

0

6
5

8.33
3

p

otal

1.11
7

T

,865
1

2
6

4


18
9
Affter

9.58

Control

intervention

1
6

9
4

4.44

Intervention

1
1

0.42
2

0

2

5
5.56

9

1

5

2

1.67

Total

8
3
6
8

.33

0
,004

1
2

4

4

7
6.25
1
3.75
8
Comment: There was no difference in attitudes between the control and intervention groups at
the time of intervention (p> 0.05). The positive attitude in the control group was 91.67% higher than
in the intervention group (44.44%). This difference was statistically significant at p <0.05.
Bảng 3.20. Comparative counseling practice
Practice counseling about

Achieve

Not

screening test
Befo

Control

n
7

Intervention

2

Total

9

re

%
1
9.44

interventio

9
1

6.67

n

0

Control

8

r
n

2
2.22

interventio

Intervention

9

3.33

9

7

Total

1

8

7.78

5.00
3

3
6

2
5.00

3

4

7

3

,831

2

1.25

8

0

1

8

2

3
6

8

3

p

otal
%
8

0.56
1

1
8.75

Affte

Achieved
n
2

T

0
,001

1
2

6

4

7
5.42
1
4.58
8
Comment: There was no difference in attitudes between the control and intervention groups at
the time before intervention (p> 0.05). The positive attitude in the control group was 91.67% higher
than in the intervention group (44.44%). This difference was statistically significant at p <0.05.
2.2.3 Hiệu quả tác động đầu ra trên đối tượng phụ nữ mang thai và chồng được sàng lọc
After 1 year of intervention:
234 pregnant women and their husbands were screened, 13 couples were diagnosed with the
disease.
01 couple is given prenatal diagnosis.
Data from the model are used as evidence of urgency and need in the process of establishing
Immunology - molecular genetics in Thai Nguyen. With the technique of diagnosing gene mutations
causing thalassemia, this study was applied. Being the first lab in Thai Nguyen to provide gene
diagnosis, prenatal diagnosis services related to thalassemia, complete the model of thalassemia
prevention for 6 Northeast mountainous areas.
Transfer the screening process, counseling for thalassemia prevention and thal screening


19
techniques by OF test for Dinh Hoa district health center. Techniques of screening HbE for Thai
Nguyen hematology and blood transfusion centre.
Transfer of molecular biology techniques to the Department of Immunology - Molecular
Genetics - Thai Nguyen National Hospital.

Figure 3. 1. The result of screening and counseling thalassemia
Comment: A total of 234 blood samples were screened (including 177 pregnant women under 12
weeks and 57 husbands agreed to do screening after knowing the wife's screening result was (+)). 97
samples (+) with screening in which 13 couples simultaneously (+) with 1 of 3 screening tests.
Results of electrophyresis determination of two couples are actually at risk of having a baby with
beta thalassemia major. 1 of the 2 couples agreed to work as pregnal diagnostic. The result of fetus
is thalassemia α0 heterozygous (--SEA), which is not included in the pregnancy termination. The
other couple does not agree to become prenatal diagnostic due to pregnancy more than 16 weeks
when detected.
Table 3. 28. The result screening by OF test for couples
Result
Subject

OF test (+)
Num
ber

OF test (-)
%

Num

%

Total

ber

Wife
68
38,42
109
61,58
177
Husband
14
24,56
43
75,44
57
Total
82
35,04
152
64,96
234
Comment: A total of 234 people (177 wives and 57 husbands) were screened for thalassemia during the
12-month period at the study site. The overall positive rate for OF screening is 35.04%.
Table 3.29. Results of screening OF compared with MCV / CMH index and Hb electrophoresis
HB electrophoresis
Total
OF test
CBC
Normal
Abnormal
n
%
MCV &/or MCH (+)
31
38
69
84,15
OF (+)
MCV&/or MCH (-)
4
9
13
15,85
Tổng
35
47
82
100
OF (-)
MCV&/or MCH (+)
3
12
15
9,87


20
MCV&/or MCH (-)
137
90,13
Total
3
12
152
100
Comment: The compatibility between OF (+) screening test with MCV / MCH (+) screening is 84.15%.
Between OF (-) and MCV / MCH (-) is 90.13%. OF screening can omit 9.87% compared to automatic
blood formula testing machine, whereas OF can detect 15.85% more suspicious cases of thalassemia
gene that MCV / MCH missed.
Table 3. 30. Hb electrophoresis results of 13 couples at risk of having fetus with thalassemia.
Couples at
risk

Screening by

Hb typing
α

CBC

Risk of fetus
β thalassemia

thalassemia

2

H

Positive

couple usband
W

s

Positive

ife
2

A2A
(HbA2>3,5%)
A2A

H

Positive

A2A

W

Positive

A2A

H

Positive

(HbA2>3,5%)
A2A

couple usband
Positive

ife
1

H

Positive

Not

heterozygous
50% β thal
heterozygous

50% HbE
heterozygous

(HbE=25,8%)
A2A

α thal

Not risk

DHT**
W

Positive

ife

A Bart’s
H-CS

H

Positive

A2A

couple usband

not
excluded
homozygous
Not

Not risk

excluded
W

s

homozygous,

EA

couple usband

7

Not

excluded *
W

25% β thal
50% β thal

excluded

ife
1

excluded

(HbA2>3,5%)

couple usband
s

Not

Positive

A2A

ife
* The fetus with the alpha thalassemia gene has not been excluded.
** If the husband does not carry the alpha gene, the child of this pair is 100% carrying the gene of which
50% α0 thal heterozygous, 50% HbCS heterozygous.

Comment: In 13 couples, they were tested for Hb electrophoresis, 6 couples had abnormal results: 2
pairs of both husband and wife carrying heterozygous beta thalassemia gene; 2 couples of wives
heterozygous beta thalassemia; 1 pair of wives heterozygous HbE; 1 pair of wives HbH-CS; The
remaining 7 pairs have normal results on Hb electrophoresis. 12/13 pairs cannot rule out the risk of
having a baby with alpha thalassemia.


21

Figure 3. 4. Results of prenatal diagnosis of alpha and beta thalassemia mutations in fetuses at
risk.
Table 3. 32. Number of subjects consulted by health workers at screening stages
Subjects consulted

Consulting
content

Pregnant women <12 weeks

OF test

Husband of wives (+) with

OF test

N
umber

1
77

screening
Couple (+) with OF screening
Couple
electrophoresis
Total

(+)

with

Result
Su
ccess
17

Fail
ure

0

7
6

57

11*

1

13

0

2

1

1

2

24

12

8
Hb
electrophoresis
Hb
Prenatal

3

diagnosis

60
8
* 7 cases of husbands working far away, 4 cases of husbands disagreeing with screening tests.
Comments: A total of 260 consultations were conducted according to the stages of the screening
process. Successful counseling for 177 pregnant women and 57 husbands for screening tests; 13 couples
doing Hb electrophoresis tests to diagnose disease; A couple makes the prenatal diagnostis for the fetus.
Failure counseling for 11 husbands who need screening and a couple need to do prenatal diagnostis.
CHAPTER IV: DISCUSSION
Epidemiological characteristics, characteristics of thalassemia genes of the study subjects and
the value of screening tests in the community
We conducted cross-sectional studies to determine the rate of carrying thalassemia gene in Dinh
Hoa district, Thai Nguyen province. Subjects of the study are 300 Tay ethnic women of reproductive age
from 15-49 years old. This is the ethnic group with the number of heads among ethnic minority groups
in Dinh Hoa, and is also at risk of carrying the gene for thalassemia higher when compared with the Kinh.
Epidemiological data of the subjects are summarized in Table 3.1.
The subjects selected were all within the reproductive age range from 15-49 years old, but more than

2.3


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