Objective: Down syndrome is the most common chromosomal disorder. There are various controversies about the necessity of polymorphism and expression of genes on chromosome 21 for the occurrence of this syndrome, the presence of expression that does not cause phenotypic effects, how many genes on the chromosome are associated with the syndrome, and which ones have increased expression. The prevalence of obesity is reported to be higher in patients with DS. An important method for screening obesity genes is genomic screening. The association of leptin (LEP) and adiponectin (ADIPOQ) with obesity has been supported by many studies. This study aimed to investigate the relationship between LEP and ADIPOQ gene polymorphism and gene expression in children with DS and to determine whether polymorphism or expression of LEP, LEPR, and ADIPOQ genes have an effect on obesity in these children.

Materials and Methods: The study included 30 children with DS followed up in the Department of Pediatrics, Faculty of Medicine, and 30 healthy children as a control group. Demographic data, anthropometric measurements, laboratory values, and echocardiography reports were recorded. Polymorphisms of LEP, LEPR, and ADIPOQ genes and mRNA expression levels of LEP and ADIPOQ genes were evaluated in these children.

Results: In this study, no significant association was found between LEP gene -2548G/A, LEPR gene Gln223Arg, ADIPOQ 276G>T gene polymorphism and obesity in children with DS, but a significant association was found between ADIPOQ45T>G gene polymorphism and obesity. The association of Leptin gene mRNA expression with obesity was investigated and a significant association was found.

Conclusions: Investigation of genetic factors that may be effective in obesity in children with Down syndrome will help to elucidate this important problem. Therefore, there is a need to determine genetic variations in the population with DS and to elucidate the genetic mechanisms of these phenotypic features.