👤 Khushdeep Bandesh

Adipocytokines, including leptin, adiponectin, and resistin, are key mediators linking adiposity, insulin resistance, and inflammation. We present the first genome-wide association study (GWAS; N = 5258) and exome-wide association study (ExWAS; N = 4578) on leptin, adiponectin, and resistin in South Asian population. We identified novel associations in genes ZNF467, and LEPREL2 for leptin; ZNF467, LEPREL2, CRLF3, ZNF732, SOX30, XIRP1, ATP8B3, SPATA2L, TMCO4, TLN2, ABCA12, and SHB for adiponectin; and D2HGDH for resistin. Additionally, we confirmed known associations of FTO, MC4R, and HOXB3 with leptin and ADIPOQ with adiponectin. Notably, ADIPOQ variants were consistently significant across GWAS, ExWAS, and gene-based analyses, reinforcing their central role in regulating adiponectin levels. Most of these novel associations identified were population-specific, highlighting the importance of studying diverse populations to uncover unique genetic signals. After adjusting for BMI, the associations with adiponectin and resistin remained significant, whereas most associations for leptin weakened in both effect size and significance. Functional annotation revealed that the identified variants were enriched for expression in adipose tissue, the brain (cerebellar hemisphere and cerebral cortex), and the pituitary gland. These variants act as eQTLs and splice-QTLs in adipose, brain, and pancreas, suggesting cross-tissue regulatory mechanisms. ExWAS further implicated rare variant burden in genes such as LONP1, ZNF335, and TTC16 for adiponectin and resistin. These findings enhance our understanding of adipocytokine biology, emphasises the need for population-specific genetic research, and lays foundation for future functional studies. Show less

Childhood obesity (OB) is influenced by complex gene-environmental interaction. While genetics of adult OB have been extensively studied, polygenic childhood OB in non-European populations is still underexplored. Furthermore, in a developing nation such as India, how the environmental component strongly modulated by the socioeconomic status (SES) shapes the genetic susceptibility is crucial to understand. A two-staged genome-wide association study (GWAS; N = 5673) and an independent exome-wide association study (ExWAS; N = 4963) were performed using a generalized linear model assuming additive effect to identify the common and rare genetic variants respectively associated with childhood OB. Rare-variant burden testing was also performed. We used the gene expression profiles and regulatory data from public databases to explain the novel associations. The implications of SES as a potential modifier of genetic susceptibility were evaluated. GWAS identified novel associations in TCF7L2, IMMP2L, IPMK, CDC5L, SNTG1, and MX1, whereas ExWAS uncovered CNTN4, COQ4, TNFRSF10D, FLG-AS1, and BMP3. Both GWAS and ExWAS validated known associations in FTO and MC4R. Furthermore, rare-variant testing highlighted the role of 101 genes. We also observed that SES can modulate the inherent susceptibility to OB. Our study identified genetic variants associated with childhood OB and highlighted the gene-environmental interaction in childhood OB. Show less

Indians, a rapidly growing population, constitute vast genetic heterogeneity to that of Western population; however they have become a sedentary population in past decades due to rapid urbanization ensuing in the amplified prevalence of metabolic syndrome (MetS). We performed a genome-wide association study (GWAS) of MetS in 10,093 Indian individuals (6,617 MetS and 3,476 controls) of Indo-European origin, that belong to our previous biorepository of The Indian Diabetes Consortium (INDICO). The study was conducted in two stages-discovery phase ( Show less

Lipids foster energy production and their altered levels have been coupled with metabolic ailments. Indians feature high prevalence of metabolic diseases, yet uncharacterized for genes regulating lipid homeostasis. We performed first GWAS for quantitative lipids (total cholesterol, LDL, HDL, and triglycerides) exclusively in 5271 Indians. Further to corroborate our genetic findings, we investigated DNA methylation marks in peripheral blood in Indians at the identified loci (N = 233) and retrieved gene regulatory features from public domains. Recurrent GWAS loci-CELSR2, CETP, LPL, ZNF259, and BUD13 cropped up as lead signals in Indians, reflecting their universal applicability. Besides established variants, we found certain unreported variants at sub-genome-wide level-QKI, REEP3, TMCC2, FAM129C, FAM241B, and LOC100506207. These variants though failed to attain GWAS significance in Indians, but largely turned out to be active CpG sites in human subcutaneous adipose tissue and showed robust association to two or more lipid traits. Of which, QKI variants showed significant association to all four lipid traits and their designated region was observed to be a key gene regulatory segment denoting active transcription particularly in human subcutaneous adipose tissue. Both established and novel loci were observed to be significantly associated with altered DNA methylation in Indians for specific CpGs that resided in key regulatory elements. Further, gene-based association analysis pinpointed novel GWAS loci-LINC01340 and IQCJ-SCHIP1 for TC; IFT27, IFT88, and LINC02141 for HDL; and TEX26 for TG. Present study ascertains universality of selected known genes and also identifies certain novel loci for lipids in Indians by integrating data from various levels of gene regulation. Show less