👤 Shruti Marwaha

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

Biallelic variants in IL6ST, encoding GP130, cause a recessive form of hyper-IgE syndrome (HIES) characterized by high IgE level, eosinophilia, defective acute phase response, susceptibility to bacterial infections, and skeletal abnormalities due to cytokine-selective loss of function in GP130, with defective IL-6 and IL-11 and variable oncostatin M (OSM) and IL-27 levels but sparing leukemia inhibitory factor (LIF) signaling. Our aim was to understand the functional and structural impact of recessive HIES-associated IL6ST variants. We investigated a patient with HIES by using exome, genome, and RNA sequencing. Functional assays assessed IL-6, IL-11, IL-27, OSM, LIF, CT-1, CLC, and CNTF signaling. Molecular dynamics simulations and structural modeling of GP130 cytokine receptor complexes were performed. We identified a patient with compound heterozygous novel missense variants in IL6ST (p.Ala517Pro and the exon-skipping null variant p.Gly484_Pro518delinsArg). The p.Ala517Pro variant resulted in a more profound IL-6- and IL-11-dominated signaling defect than did the previously identified recessive HIES IL6ST variants p.Asn404Tyr and p.Pro498Leu. Molecular dynamics simulations suggested that the p.Ala517Pro and p.Asn404Tyr variants result in increased flexibility of the extracellular membrane-proximal domains of GP130. We propose a structural model that explains the cytokine selectivity of pathogenic IL6ST variants that result in recessive HIES. The variants destabilized the conformation of the hexameric cytokine receptor complexes, whereas the trimeric LIF-GP130-LIFR complex remained stable through an additional membrane-proximal interaction. Deletion of this membrane-proximal interaction site in GP130 consequently caused additional defective LIF signaling and Stüve-Wiedemann syndrome. Our data provide a structural basis to understand clinical phenotypes in patients with IL6ST variants. 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