Background. Over the last few years, the importance of leptin in energy metabolism has been extensively studied in both animal models and in humans. Very few results are available on the association between human leptin gene (LEP) variants and obesity traits in India. We designed this study to analyse the polymorphisms in human leptin gene and the association of sequence variants with obesity among the population in Kerala, South India. Methods. In this case-control design of 148 study participants, data were collected on socioeconomic aspects and anthropometric measurements. Plasma glucose, insulin, leptin, and lipid profile were measured. Genotyping was done by automated DNA sequencing. Results. The common Single Nucleotide Polymorphism (SNP) of 5′-UTR of LEP − 2548G/A was found to be present in the study population with “A” variant as dominant allele. A novel synonymous mutation Thr5Thr of exon 2 of LEP was identified in heterozygous form in one subject with morbid obesity with hyperleptinemia. A novel missense mutation Phe17Leu was observed in two subjects with obesity in heterozygous condition. A novel missense mutation Lys36Arg in exon 2 of LEP was observed in one subject with abdominal obesity and decreased serum leptin level. Conclusion. LEP − 2548G/A at 5′-untranslated region was found to be common with the mutant “A” variant in the study population. SNPs of exons in LEP were found to be rare but associated with morbid obesity and altered levels of serum leptin in the study population in Kerala, India.

Objectives: TAR DNA-binding protein of 43 kDa (TDP-43) is an RNA/DNA binding protein expressed in the brain and the testis. Mutations in TDP-43 lead to mislocalization and cytoplasmic aggregation of this protein causing neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal dementia. TDP-43 has also been implicated in maintaining spermatogenesis. While homodimerization of TDP-43 is critical for its physiological functions, higher-order aggregation of this protein impairs its functions. This study was aimed to map the critical amino acids of the N-terminus of this protein in mediating its homodimerization. Materials and Methods: We generated deletion constructs of Tdp-43 containing NRRM1 domain alone (TDP-43∆3-183) and N-terminal peptide of TDP-43 which lacks the nuclear localization signal (NLS) (TDP-43∆1-50) with fluorescent reporters having non-overlapping emission properties. These constructs were co-transfected into a mouse spermatogonial cell line to examine their dimerization and nuclear translocation capabilities in vitro. Results: We found that TDP-43∆3-183 alone was not capable of homodimerization. On the other hand, TDP-43∆1-50 when co-transfected into GC1-spg cells along with full length TDP-43 translocated to the nucleus oligomerized with the latter and translocated to the nucleus, indicating the importance of amino acids 1-50 of TDP-43 in dimerization. Conclusion: The N-terminal segment of TDP-43 spanning amino acids 1-50 is responsible for dimerization, while that spanning amino acids 51-183 directs it to the nucleus.The physiological and pathological implications of this finding need to be examined.