Diversity of sickle cell trait in Jharkhand state in India: Is it the zone of contact between two geographically and ethnically distinct populations in India.

Incidence of sickle cell trait in India is high in peninsular south, south-eastern, central and south-western India, while in north and north-eastern India, it is absent. Unicentric origin of SCD in the tribals of nilgiri hills in southern India has been proposed. The present study on the frequency of HbS trait and -globin gene haplotypes was conducted in the tribal-rich states of Chhattisgarh and Jharkhand to get an insight into the uneven distribution of HbS in India. Jharkhand borders with the HbS-high Odisha and Chhattisgarh, and HbS-low UP, Bihar and Bengal. Cellulose acetate gel electrophoresis was performed on the collected blood samples, to detect sickle haemoglobin (HbS) followed by DNA analysis. HbS associated -gene haplotype was constructed for the samples positive for HbS and all the tribals by PCR-RFLP. Out of 805 (Chhattisgarh – 261, Jharkhand – 544; >36% tribals) samples analysed HbS frequency was 13% in Chhattisgarh and 3.3% in Jharkhand. Within Jharkhand, frequencies varied considerably from 10% in Tatanagar to nil in Sahibganj. The Arab-India (AI) haplotype of -globin cluster occurred in low frequency, confined mainly to Chhattisgarh. The most abundant haplotype in all the populations was the East Asian, + − − − − − +, rare in HbS, mainly in Sahibganj in east Jharkhand, which lacked AI. Our results indicate that besides the heterozygote advantage againstmalaria, the uneven regional distribution of HbS trait is because of restricted movement of two different populations, Dravidian from the south and Tibeto-Burman from the east into the Indianmainland which failed tomeet, we conjecture, due to severe climatic conditions (deserts and heat) prevailing through parts of central India. Apparently, Jharkhand became a zone of contact between them in recent times.

Lower incidence of nonsyndromic cleft lip with or without cleft palate in females: Is homocysteine a factor.

In India, as in other parts of the world, nonsyndromic cleft lip with or without cleft palate (NSCL±P) is a highly prevalent birth defect, its incidence in males being twice that in females. A case–control association study has been carried out with respect to homocysteine level and MTHFR C677T, A1298C and SLC19A1 (RFC1) G80A genotypes from an eastern Indian cohort to investigate whether Hcy and other Hcy-pathway genes also contribute to the risk level. While MTHFR 677T and SLC19A1 80G are individually and cumulatively risk factors, SLC19A1 80A appears to be protective against MTHFR 677T risk allele. Elevated Hcy associates with NSCL±P both in case mothers and cases. Significantly, this difference shows a gender bias: the level of elevation of Hcy in female cases is distinctly higher than in males, and more case females are hyperhomocyteinemic than the case males. It implies that compared with the males, higher level of Hcy is needed for NSCL±P to manifest in the females. We consider this as one of the possible factors why the incidence of this disorder in females is much lower than in males.

Y-haplotypes and idiopathic male infertility in an Indian population.

Infertility being a multifactorial disorder, both genetic and environmental factors contribute to the etiology of infertile phenotype. Chromosomal anomalies and Y-microdeletion are the established genetic risk factors of male infertility. Y-haplotypes has been found as risk factor for male infertility in certain populations, though in certain others no association has been reported, suggesting a population-specific association of these variations with male infertility. In a case-control study, 165 azoo-/oligospermic patients and 200 controls were haplotyped for certain Y-haplogroups for a possible association with idiopathic male infertility in an Indian population. Analysed Y-haplogroups showed no association with infertile phenotype. Thus this genetic factor is not a risk for infertility in the studied Indian population but that does not rule out the possibility of any of them, to be a risk in other populations.

Hepatocellular carcinoma presenting as neutrophilic leukaemoid reaction--a rare entity.

Leukaemoid reaction is a rare, growth factor-driven, paraneoplastic manifestation of hepatocellular carcinoma. It may masquerade as the neutrophilic chronic myeloid leukaemia or as chronic neutrophilic leukaemia. A 52-year-old male presented with hepatosplenomegaly and severe leucocytosis. He had progressive leucocytosis, neutrophil alkaline phosphatase score elevated, liver function tests altered. FNAC from the mass in the liver revealed features of moderately differentiated hepatocellular carcinoma. The patient deteriorated within two weeks and died thereafter.

Male infertility: Y-chromosome deletion and testicular aetiology in cases of azoo-/oligospermia.

The spermatogenesis locus azoospermia factor (AZF) in Yq11 has been delineated into three microdeletion intervals designated as AZFa, AZFb andAZFc. AZFc is the most frequently deleted region. We have studied 270 male infertile patients for various genetic disorders associated with infertile phenotype. In this study, we have presented results of our studies on Y-chromosome deletions, chromosomal abnormalities (Klinefelter syndrome) and histology of testis with the objective of seeing whether there were cases of gonosomic mosaicism and a causal correlation between the genetic disorder; and testicular aetiology could be drawn. In all the 13 cases of Y-chromosome microdeletion, AZFc region and DAZ gene were deleted, while no case of AZFa deletion was detected. This result was at variance with other reports from India, where a considerable fraction of cases showed deletion in AZFa region of the Y-chromosome. Both Y-deleted and non-Y-deleted cases revealed heterogeneous testicular phenotype with comparable severity. This disparity among testicular phenotype in cases with known genetic aetiology and even in cases of unknown aetiology can be attributed to different genetic backgrounds and effect of modifiers. Since male infertility is a multifactorial disorder, the contributions of environmental and occupational insults may not be underestimated.

Analysis of topological organization of chromatin during spermatogenesis in mouse testis

Eukaryotic chromatin is organized as radial DNA loops with periodical attachments to an underlying nucleoskeleton known as nuclear matrix. This higher order chromatin organization is revealed upon high salt extraction of cells. To understand the sequential change in the functional organization of chromatin during spermatogenesis, we have analysed the higher order organization of chromatin in different testicular cell types and the epididymal sperm of laboratory mouse. The expansion and contraction of the nucleoid DNA following 2 M NaCl extraction was measured in a fluorescence microscope using ethidium bromide (2.5-200 mg/mL) as an intercalating dye to induce DNA positive supercoils. While the halo size varied among cell types (pachytene DNA most extended, round spermatid least), 5 mg/mL ethidium bromide (EtBr) removed maximum negative supercoils in all the cell types. At higher EtBr concentrations, maximum positive supercoiling occured in pachytene DNA loops. Consistent with this, the pachytene looped domains were maximally sensitive to DNase I, while the elongated spermatids and sperms were highly resistant. Our data suggest that pachytene DNA is in the most open chromatin conformation of all testicular cell types, while round spermatids show the most compact conformation in terms of EtBr intercalation.

Inactivation of mammalian X-chromosome during spermatogenesis: Temporal expression of genes in the laboratory mouse.

At zygotene/pachytene stage of meiosis in mammalian testis, the X—Y heterobivalent is sequesterd into a heterochromatinized body whose genetic inactivity is shown by lack of uridine incorporation. For the genic level evaluation of the X-inactivation, activities of three X-linked genes were assayed in testicular cell types in the laboratory mouse. While hypoxanthine phosphoribosyl transferase is functional at least up to pachytene stage of primary spermatocytes, glucose-6-phosphate dehydrogenase appears to be active only in the Sertoli cells. No transcript of the muscle specific muscular dystrophin gene was obtained from its regular 5' promoter. Thus, inactivation of X-linked genes in testis occurs at different stages during spermatogenesis, independently of heterochrornatinizati on of the XY-body. We propose that Xist transcript, the putative regulator of X-inactivation in female soma, is also the regulator in testis. However, due to its extremely low level in testis the transcript may regulate by "spreading" in a gradient and affect the genes in a temporal order. Thus, besides other factors, physical proximity of the genes to Xist may determine the stage of their inactivation.