Articles written in Journal of Genetics
Volume 95 Issue 3 September 2016 pp 505-513 RESEARCH ARTICLE
Methylenetetrahydrofolate reductase (MTHFR) is the most important gene that participates in folate metabolism. Presence of valine instead of alanine at position 677 and elevated levels of homocystein causes DNA hypomethylation which in turnfavours nondisjunction. In this study, we conducted a meta-analysis to establish link between maternal single-nucleotide polymorphism (SNP) and birth of Down’s syndrome (DS) child. A total of 37 case–control studies were selected for analysis including our own, in which we investigated 110 cases and 111 control mothers. Overall, the result of meta-analysis showed significant risk of DS affected by the presence of maternal SNP (MTHFR 677 C–T OR= 0.816, 95% CI= 0.741–0.900, P< 0.0001). Heterogeneity of high magnitude was observed among the studies. The chi-square value suggested a highly significant association between homozygous mutant TT genotype and birth of DS child (χ ²=23.63, P= 0.000). Genetic models suggested that ‘T’ allele possesses high risk for DS whether present in dominant (OR = 1.23, 95% CI = 1.13–1.34); codominant (OR = 1.17, 95% CI = 1.10–1.25) or recessive (OR = 1.21, 95% CI = 1.05–1.38) form. The analysis from all 37 studies combined together suggested that MTHFR 677 C–T is a major risk factor for DS birth.
Volume 95 Issue 4 December 2016 pp 887-894 RESEARCH ARTICLE
Human reproduction is considered as the most inefficient event as ∼15–20% of human pregnancies end in miscarriage and in the product of miscarriages, chromosomal anomalies are a common occurrence. The aim of the present retrospective study was to assess the frequency of chromosomal aberrations in couples with recurrent miscarriages in the region of Punjab and to compare with worldwide frequencies. In this study, a total of 440 cases were referred between the period 1995– 2015. After lymphocyte culturing, giemsa–trypsin banding was done for each case to assess the chromosomal anomalies. The frequency of chromosomal aberrations among couples was found to be 3.41% in our study. Among these aberrations, balanced reciprocal translocations formed the largest group with 60% anomalies. We would conclude that clinicians should understandthe importance of chromosomal analysis in these couples and refer them for karyotyping after two miscarriages to rule out the possible genetic cause of recurrent miscarriages.
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