Maternal association and influence of DHFR 19 bp deletion variant predisposes foetus to anencephaly susceptibility: a family-based triad study

OBJECTIVE

Previous studies have not used family-based methods to evaluate maternal-paternal genetic effects of the folate metabolizing enzyme, dihydro folate reductase (DHFR) essential during embryogenesis. Present study focuses on evaluating the association and influence of parental genetic effects of DHFR 19 bp deletion in the development of foetal neural tube defects (NTDs) using family-based triad approach.

MATERIALS AND METHODS

The study population (n = 924) including 124 NTD case-parent trios (n = 124 × 3 = 372) and 184 healthy control-parent trios (n = 184 × 3 = 552) from Telangana, India, was genotyped for DHFR 19 bp deletion. Statistical analysis was used by SPSS and parent-of-origin effects (POE).

RESULTS

Foetuses with deletion genotype (DD) were at risk of developing anencephaly (OR = 3.26, p = 0.020). Among parents, increased maternal risk of having an anencephaly foetus (OR = 2.66, p = 0.028) was observed in mothers with DD genotype. In addition, POE analysis also demonstrated higher risk of maternal transmission of the deletion allele to anencephaly foetus compared with paternal transmission (OR = 6.00, p = 0.016). Interestingly, maternal-paternal-offspring genotype incompatibility revealed maternal deletion genotype (DD) in association with paternal heterozygous deletion genotype (WD) significantly increased risk for NTDs (OR = 5.29, p = 0.013).

CONCLUSIONS

This study, using family-based case-parent and control-parent triad approach, is the first to report influence of maternal transmission of DHFR 19 bp deletion in the development of anencephaly in the foetus.

Seroprevalence and Influence of Torch Infections in High Risk Pregnant Women: A Large Study from South India

BACKGROUND

The increased complications to the mother and fetus during or after pregnancy and birth are often caused by a wide array of pathogenic organisms mostly belonging to the TORCH group [toxoplasmosis, rubella, cytomegalovirus (CMV), and herpes simplex virus (HSV)]. These agents cause asymptomatic or mild infection in the mother while serious consequences in fetus. The present study was aimed to find significant etiological pathogens in the causation of high risk pregnancy (HRP) in South Indian population.

MATERIAL AND METHODS

A total of 1,158 HRP women (2010-2013) from Modern Government Maternity Hospital, Hyderabad were considered. Two milliliter of blood was obtained and the serum was analyzed for IgG and IgM antibodies against TORCH agents by ELISA.

RESULTS

Twenty-five percent of the study group had fetal congenital malformation in the present pregnancy (Group 1; N = 291) while 75 % showed bad obstetric history (BOH) (Group 2; N = 867). Maternal age of ≤25 years, primi gravida, and consanguinity showed predisposing role for Group 1 while maternal age ≥30 years and ≥ 3 gravida were contributing risk for Group 2. The seropositvity in HRP women for toxoplasma, rubella, CMV, and HSV was 28, 84, 92, and 61 %, respectively for IgG while it was 6, 3, 4, and 3 % for IgG + IgM. Total seropositvity of toxoplasma, rubella, CMV, and HSV in Group 1 was 29, 97, 97, and 62 % while it was 36, 84, 97, and 65 % in Group 2, respectively.

CONCLUSION

Maternal age of ≤25 years, primi gravida, and consanguinity contributed to fetal congenital malformation in the present pregnancy while maternal age of ≥30 years and ≥ 3 gravida towards BOH. Toxoplasma is protective while rubella and CMV are the infectious agents for HRP. Among the groups, toxoplasma and rubella conferred a predisposing risk towards Group 2 and Group 1, respectively. Sixty-one percent seropositvity of HSV in relation to bad obstetric outcome is the highest prevalence reported so far in India.