MINISTRY OF EDUCATION
MINISTRY OF HEALTH
HANOI MEDICAL UNIVERSITY
  

VU THI HUYEN

EVALUATE THE VARIABILITY OF SOME GENES
ENCODING XENOBIOTIC METABOLISM IN
INFERTILE MEN

Specialization : Biomedical - Genetic
Code
: 62720111

SUMMARY OF DOCTORAL DISSERTATION

HANOI - 2019


THIS STUDY WAS COMPLETED IN:
HANOI MEDICAL UNIVERSITY

Spervisor: 1. Assoc. Prof. MD. Tran Duc Phan
2. PhD. Nguyen Thi Trang

Reviewer 1: Assoc. Prof. MD. Phan Thi Hoan
Reviewer 2: Assoc. Prof. MD. Tran Van Khoa
Reviewer 3: Assoc. Prof. MD. Nguyen Nam Thang

The thesis will be defended before the Examining Board at

technique to determine polymorphisms of CYP1A1, NAT2 and
GSTP1 genes: CYP1A1 2455A>G, NAT2 481C>T, NAT2 590G>A,
GSTP1 313G>A, GSTP1 341C>T were higher in the infertile group
than in the control group.
The study found that CYP1A1 2455A>G genotype AG
increased the risk of male infertility 4.09 times, polymorphism NAT2
481C>T (rs1799929), CT genotype increased the risk of male
infertility by 4.1 times, polymorphism NAT2 590G>A (rs1799930)
genotype GA increased the risk of male infertility by 3.3 times,
GSTP1 313G>A increased the risk of male infertility by 3.25 times,
GSTP1 polymorphism 341C>T (rs1138272), CT genotype increased
the risk of male infertility 6.9 times. Combining 2 polymorphisms
GSTP1 and NAT2 or CYP1A1 and NAT2 or GSTP1 and CYP1A1


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increased the risk of infertility than only one polymorphism. In this
research, we found that the gene polymorphic complexes of male
infertility in Vietnam include: Gene polymorphisms combination
[GSTP1 (341C> T); NAT2 (590G> A); CYP1A1 (2455A> G)] or
[GSTP1 (341C> T); CYP1A1 (2455A> G); NAT2 (481C> T)]
expression of additive interaction, but [NAT2 (590G> A); CYP1A1
(2455A> G)] or [CYP1A1 (2455A> G)]; NAT2 (481C> T)] is a
complementary interaction. Using oxysperm kit, we found that
infertile men with mutations in the xenobiotics metabolism are 29.87
times increased risk of oxidative stress than those who do not.
The structure of the thesis:
The thesis included 122 pages with 27 tables, 21 figures and 1
graphs, 193 references, of which 178 are in English and 15
Vietnamese. Thesis structure including 2 pages introduction, 39 page

GnRH, GH, Testosterone, Inhibin participate in the process of
sperm establist as well as the differentiation and development of
sperm.
1.2.4. Pathology affects male fertility
The common diseases that affect the number and quality of sperm
are: varicocele, testicular inflammation, testicular cancer, systemic
diseases, infections ...
1.2.5. Age of reproduction
Studies have shown that the higher the age, the less number sperm
decreases.
1.2.6. Environment
The most common environmental factors causing male infertility
are heavy metals, cigarette smoke, ethylene dibromide, chromium,
ethylene dibromide, pesticides, dioxin... These agents inhibit the
growth of sperm reducing, density and mobility of sperm reducing.
1.3. Xenobiotics and the metabolism of xenobiotics in the body
Xenobiotics are chemicals that are not produced by the organism,
which, if not metabolized and excreted by the body, will cause
increasing free radicals, which oxidize the molecule, and causes
DNA to mutate. And causing diseases including infertility in men.
1.4. Genes coding for the enzyme metabolize xenobiotics primarily
1.4.1 CYP1A1 gene


4
In the cytochrome P450 system, CYP1A1 is the major enzyme
responsible for the metabolism of aromatic hydrocarbons, heterocyclic
amino acids. If this metabolism is not good leads to increased free
radicals causing DNA changes leading to infertility in men.
CYP1A1 is a gene on the 15th chromosome (15q24.2-4) consist of



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smallest p, so the sample size is large). C: Constants are related to
type I and type II errors. Take the value α= 0.05; β = 0.2 then C =
7.85. Replace the values into n = 82.5. In fact, we studied the 170
infertile group and the 170 control group.
2.1.2. Criteria for selecting research subjects
Infertility group: unknown reason infertility male: with
azoospermia or severe oligospermia (G

481C>T

590G>A


49.4

CT

86

50.6 0.506

TT

0

0

GG

71

41.8

GA

91

53.5 0.535

AA

8


38.2 0.382

TT

0

0

H0

χ2 (p)

He
15.3
0.403 (pA of the GSTP1 gene, all other
genes with a different distribution to the Hardy-Weinberg distribution

higher than the control group; Incorporating GA + AA, infertility
increased 5.16 times; AG GSTP1 gene localization at position 313
increased the risk of infertility 3.25 times, heterologous and mutant
genotypes (GA and AA) increased the likelihood of infertility 5.16.
The mutant carriers (A) increased the risk of infertility by 5.18 times.
With the GSTP1 341C>T gene polymorphism (rs1138272): the
rate of mutant genotypes in the infertile group was higher than that of
the control group. The mutant and mutant genotypes of GSTP1 at
position 341 increased the risk of infertility by 6.9. The mutant (T)
gene of GSTP1 at 341 increased the risk of infertility by 5.5 times
that of normal allelic carriers (C).
4.3. Correlation between common nucleotid variants of CYP1A1,
GSTP1 and NAT2 genes for male infertility


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4.3.1. Correlation between polymorphisms of CYP1A1, GSTP1 and
NAT2 with male infertility
According to our study, people with genotype (590GA or 590AA)
and (2455AG or 2455GG), the risk of infertility increased 4.86 times;
Except for genotypes that carry only one of the 590GG polymorphisms
and 2455AG or 2455GG and 2455AA and 590GA or 590AA.

People with both polymorphism (481CT or 481TT) and (2455AG
or 2455GG) increased the risk of infertility by 6.37 times. We have
not found any authors to study the association of CYP1A1 2455A>G
and NAT2 (590G>A) polymorphisms; (481C>T) with male infertility.
Our study found that the greater the polymorphism of CYP1A1,
NAT2, the higher the risk of infertility.
Persons with simultaneous CYP1A1 polymorphism (2455A>G) and

By MDR software we analyze genetic combinations and build
Dendrogram maps. Results: Combinations of GSTP1 (341C>T) and
CYP1A1 (2455A>G) and NAT2 (590G>A) polymorphisms; or
GSTP1 (341C>T) and CYP1A1 (2455A>G) and NAT2 (481C>T)
show cumulative interaction, in which CYP1A1 (2455A>G) and
NAT2 (590G>A) or CYP1A1 (2455A>G) and NAT2 (481C>T) are
complementary interactions. Therefore, individuals with mixed
polymorphic genes have a significantly increased risk of male
infertility.
Our study indicates that combinations of GSTP1, NAT2 and
CYP1A1 polymorphisms may increase the risk of infertility. This may
be due to oxidative stress due to excessive activity of ROS leading to
alterations in GSTP and CYP1A1 genes and non-recovery of sperm
DNA by abnormal metabolism when transgenic NAT2.
4.3.2. Relationship between oxidative stress levels in semen in male
patients with polymorphisms in xenobiotics metabolism
OS has four levels from 1 to 4 and is divided into two groups of
HOS (including Levels 3 and 4) and LOS (Level 1 and 2 OS).
Comparison between the two groups: Patients with spermatozoa in


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semen and at least one polymorphisms that metabolize xenobiotics;
Controls are those without any gene polymorphism. We collected 71
patients in the disease group and 72 patients in the control group. In
the group of patients, high OS (HOS) was 78.9%, low OS (LOS) was
21.1%. In contrast, in the control group, high OS (HOS) was only
11.1%, low OS was 88.9%. This suggests that infertile men with
polymorphisms that metabolize xenobiotics have a 29.87-fold higher
risk of oxidative stress than normal people. The difference was

14.7% and 0%; Frequency of GA and AA genotypes 341C>T in the
inferior group was 38.2%; in the control group was 8.2%.
2. Relationship between polymorphism of GSTP1, NAT2, and
CYP1A1 with infertility
- Polymorph CYP1A1 2455A> G, A allele replaced by G allele
increases the risk of male infertility compared to A allele 3.27 times.
- Polymorphic NAT2 481C> T (rs1799929), C allele replaced by T
allele increased the risk of infertility compared to C allele up 3.05 times.
- Polymorph NAT2 590 G> A (rs1799930), G allele replaced by A
allele increases the risk of male infertility compared to G allele 3.09
times.
- GSTP1 313G polymorphism> A: G allele was replaced by A allele
to increase the risk of male infertility compared to G allele 5.18 times.
- GSTP1 341C> T polymorphism (rs1138272): C allele replaced
by T allele increased the risk of male infertility compared to C allele
5.5 times.


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Combining 2 polymorphs:
- Combining two GSTP1 and NAT2 polymorphisms, the risk of
infertility is higher when there is only one type of polymorphism.
- Combining two polymorphisms CYP1A1 and NAT2 the risk of
infertility is higher when there is only one type of polymorphism.
- Combining 2 polymorphisms GSTP1 and CYP1A1 are at higher
risk of infertility when there is only 1 polymorphic type.
Combining the polymorphisms of NAT2, GSTP1 and CYP1A1:
Complex GSTP1(341C>T); NAT2(590G>A); CYP1A1(2455A>G)
with 100% reproducibility and prediction error of 30.8%. Type
GSTP1 (341C>T); NAT2 (590G>A); CYP1A1 (2455A>G); NAT2