Insertion/Deletion polymorphisms do play any role in G6PD deficiency individuals in the Kingdom of the Saudi Arabia

Polymorphisms of genes related to phase II metabolism and resistance to clopidogrel

Clopidogrel is an antiplatelet drug commonly used to prevent coagulation. This review aimed to investigate the effect of polymorphisms of G6PD, GCLC, GCLM, GSS, GST, GSR, HK and GLRX genes on clopidogrel during phase II metabolism through exploring previous studies. The results revealed that low glutathione plasma levels caused by several alleles related to these genes could affect the bioactivation process of the clopidogrel prodrug, making it unable to inhibit platelet aggregation perfectly and thus leading to severe consequences in patients with a high risk of blood coagulation. However, the study recommends platelet reactivity tests to predict clopidogrel efficacy rather than studying gene mutations, as most of these mutations are rare and other nongenetic factors could affect the drug's efficacy.

Deleterious effect of angiotensin-converting enzyme gene polymorphism in vitiligo patients

Vitiligo is a rare skin condition caused by an immune reaction. Vitiligo can occur anywhere on the body. This proposed explanation of vitiligo makes it clear that vitiligo is not linked to any other autoimmune diseases. The polymorphisms of some genes present in the immune system play a major function in susceptibility of vitiligo. Meta-analysis studies have shown that the Angiotensin converting enzyme (ACE) gene insertion and deletion polymorphism is closely associated with vitiligo in many ethnicities. The connection between ACE gene and vitiligo is connected through the auto immune diseases and there are no genetic polymorphism studies have been carried out with ACE gene with vitiligo in the Saudi population. Previous studies show that vitiligo patients are more likely to also have an autoimmune disorder. The current study aims to investigate the I/D polymorphism in the ACE gene with diagnosed patients with vitiligo subjects. This is a case-control study carried out in the Saudi population with 100 vitiligo cases and 100 healthy controls. Genotyping was performed through polymerase chain reaction followed by 3% agarose gel electrophoresis. Genotype and allele frequencies were carried out with genetic mode of inheritances. Statistical analysis was performed considering p < 0.05 as significant association. There was a substantial difference in allele frequency distribution between vitiligo patients and healthy controls (OR-1.70 (95%CI: 1.14-2.53); p = 0.008). Additionally, DD genotype (OR-4.71 (95%CI: 1.42-15.61); p = 0.008) and recessive model (OR-2.66 (95%CI: 1.41-5.02); p = 0.002) was strongly associated. Both dominant and co-dominant showed the negative association (p > 0.05) when compared between the vitiligo cases and controls. The correlation between age and genotyping was performed with Anova analysis and current study results confirmed the substantial link between 11 and 20 years (p = 0.01) and 31-40 years (p = 0.04) with the defined age groups. In conclusion, in Saudi populations, the ACE gene I/D polymorphism was identified as being correlated with vitiligo. This is the first study in Saudi Arabia to report the risk factors of vitiligo with the ACE gene polymorphism.

Next generation sequencing (NGS) in glucose-6-phosphate dehydrogenase (G6PD) deficiency studies

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is commonly observed in human males. It is a genetic disorder affecting the red blood cells. The diagnosis of G6PD is usually based on blood analysis and there is no specific molecular or genetic test. The complete gene sequence of G6PD is known for different ethnicities. Known single nucleotide polymorphism (SNP) associated with G6PD is available in the public databases. Hence, robust, fast and efficient sequencing of G6PD is critical in disease diagnosis. The application of next generation sequencing (NGS) with its high reliability is useful in G6PD diagnosis.

Insertion and deletion polymorphism in the alpha-2B adrenoceptor gene in pregnant women ripens gestational diabetes mellitus

There are no earlier studies that reported the association of the 12Glu9 polymorphism in the alpha-2B adrenoceptor (ADRA2B) gene with gestational diabetes mellitus (GDM). We examined the potential association between the ADRA2B gene insertion/deletion (I/D) polymorphism in the Saudi population with GDM. Pregnant women with GDM have been reported to exhibit the same susceptibility as that observed in type 2 diabetes mellitus (T2DM). We have selected I/D polymorphism of the ADRA2B gene located in chromosome 2q11.1 that has been extensively related to T2DM and cardiovascular diseases. This case–control study was conducted with 200 GDM and 300 non-GDM pregnant women. Genotyping of I/D polymorphism was performed by conventional PCR method. Biochemical analyses were found to be significantly different between GDM and non-GDM subjects (p < 0.05). Genotype (ID + DD vs II, p = 0.0002) and allele (D vs I, p = 0.0002) frequencies of the 12Glu9 polymorphism were found to be statistically significant. However, a significant difference was found between allele and genotypes of I/D polymorphism of the ADRA2B gene or the clinical characteristics of the subjects. Our results obtained in this study indicate the ADRA2B gene in the Saudi women was associated with the development of GDM.

Genetic polymorphisms in paraoxonase 1 and G protein-coupled receptor 77, and the risk of glucose-6-phosphate dehydrogenase deficiency in a Saudi population

Objectives:

To investigate the role of amino acid substitution variants Q192R and C698T in the development of glucose-6-phosphate dehydrogenase (G6PD) deficiency in a Saudi male population.

Methods:

This case-control study was carried out in 200 Saudi male individuals: 100 patients with G6PD deficiency, and 100 control subjects collected between July and August 2011 in the Taif region of Saudi Arabia. A total of 2100 male Saudi individuals were screened by a fluorescence spot test, and 100 with G6PD deficiency were selected. Two common variants PON1 (rs662) and C5L2 (rs149572881) were genotyped using polymerase chain reaction followed by restriction fragment length polymorphism analysis.

Results:

The results showed that the R allele and QR genotype were associated with the Q192R polymorphism in PON1 (R versus Q odds ratio [OR], 1.72; 95% confidence interval [95% CI], 1.1-2.6; p=0.01; and QR versus QQ: OR, 1.98; 95% CI, 1.1-3.6; p=0.02). All the C698T genotypes and allele frequencies in C5L2 were almost similar in both the cases and controls (CT versus CC: OR, 2.04; 95% CI, 0.3-11.4; p=0.40; and T versus C: OR, 2.02; 95% CI, 0.3-11.1; p=0.41).

Conclusions:

These findings suggest the association of PON1 with G6PD deficiency in the Saudi male population studied herein. Future studies, including correlation analyses between the clinical features and genotypes in populations of different ethnicities, are warranted to confirm the disease association with these genetic mutations.

Prevalence of glucose-6-phosphate dehydrogenase deficiency and the role of the A- variant in a Saudi population

OBJECTIVES

To estimate the prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency among Saudi men, and to establish the frequency of the two mutations/polymorphisms associated with the G6PD A- mutation--G to A at nucleotide 202 (G202A) and A to G at nucleotide 376 (A376G)--in those found to have G6PD deficiency.

METHODS

Blood samples were obtained from healthy male Saudi donors and screened for G6PD deficiency using a fluorescent spot test. Samples from subjects shown to be G6PD deficient and controls were then analysed for the presence of the G202A and A376G mutations on exons 4 and 5, respectively, of the G6PD gene using polymerase chain reaction followed by restriction fragment length polymorphism.

RESULT

A total of 2100 male subjects were screened; of these, 100 (4.76%) were shown to be G6PD deficient. The G6PD A- mutation (presence of both G202A and A376G) was observed in two (2%) of the 100 subjects with G6PD deficiency. There was no significant difference in the frequency of this mutation between those with G6PD deficiency and controls.

CONCLUSION

The G6PD A- mutation (G202A and A376G) does not appear to have a role in G6PD deficiency in a Saudi population.

Association of angiotensin converting enzyme gene insertion/deletion polymorphism and familial hypercholesterolemia in the Saudi population

BACKGROUND

The study of the association between genotype and phenotype is of great importance for the prediction of multiple diseases and pathophysiological conditions. The relationship between angiotensin converting enzyme (ACE) Insertion/Deletion (I/D) polymorphism and Familial Hypercholesterolemia (FH) has been not fully investigated in all the ethnicities. In this study we sought to determine the frequency of I/D polymorphism genotypes of ACE gene in Saudi patients with FH.

RESULTS

This is a case-control study carried out purely in Saudi population. Genomic DNA was isolated from 128 subjects who have participated in this study. ACE gene I/D polymorphism was analyzed by polymerase chain reaction in 64 FH cases and 64 healthy controls. There was no statistically significant difference between the groups with respect to genotype distribution. Furthermore, we did not find any significant difference in the frequency of ACE I/D polymorphism in FH subjects when stratified by gender (p = 0.43).

CONCLUSION

Our data suggest that ACE gene I/D polymorphism examined in this study has no role in predicting the occurrence and diagnosis of FH.

G6PD Enzyme Deficiency in Neonatal Pathologic Hyperbilirubinemia in Yazd

BACKGROUND

About 7.5% of the world population carries one or two deficient copy of glucose-6-phosphate dehydrogenase (G6PD) genes. According to WHO, its prevalence in Iran is 10 to 14.9%. This study aimed on determination of frequency of G6PD deficiency in neonates with jaundice who were hospitalized during 6 months (September 2008 to February 2009) in the city of Yazd, Iran.

MATERIALS AND METHODS

In this study, 105 icteric neonates in the hospitals of Yazd were evaluated. Data was collected from hospital records, and the G6PD activity was measured by photometric biochemical assay. Statistical analysis of data was performed by the SPSS-16 software, using Student's t-test and Pearson's chi-squared test.

RESULTS

Between all of studied neonates, 19 (18.1%) had G6PD deficiency, and consisted of 15 boys (29.4% of boys) and 4 girls (7.4% of girls). In 100% of cases, the jaundice began in the first week after birth. The average total serum bilirubin at hospitalization was 17.22 mg/dL. In 31.5% of the G6PD-defficient neonates, exchange transfusion became necessary, which is significantly more than the rate in G6PD-sufficient (4.6%) neonates (P-value<0.05).

CONCLUSION

In general, the frequency of G6PD deficiency in this study seems quite high. Regarding its severity and frequent need for exchange transfusion, we recommend that all of the icteric neonates should be evaluated for G6PD activity. Also, it is better to test for G6PD deficiency in all of the neonates, to detect its presence and to prevent its complications such as favism and oxidant drug-induced hemolysis, since the test has a low cost.