Obesity is commonly classified into subgroups depending on suspected etiology: monogenic obesity (extremely severe obesity in the absence of developmental delays), syndromic obesity (clinically obese subjects additionally distinguished by mental retardation, dysmorphic features, and organ-specific developmental abnormalities), and polygenic or common obesity, which affects the general population. obesity in humans is a complex polygenic trait with high inter-individual heritability estimated at 40–70%. candidate gene, dna linkage and genome-wide association studies (gwas) have allowed for the identification of a large set of genes and genomic regions associated with obesity. structural chromosome abnormalities usually result in congenital anomalies, growth retardation and developmental delay. occasionally, they are associated with hyperphagia and obesity rather than growth delay. common cytogenetic polymorphisms detected by g-banding are considered as heteromorphisms and are believed to have no impact on phenotype and include heterochromatin regions of chromosomes 1, 9, 16 and y and also prominent acrocentric short arms, satellites and stalks. recent studies indicated the likely role of chromosome heteromorphisms in infertility. chromosome analyses have been studied in large groups of infertile patients in recent years. in some of these studies, chromosome heteromorphisms were reported to have a higher frequency than the normal population and were regarded as abnormalities.they include varying sizes of heterochromatin blocks, satellite or repeat sequence regions and inversions. in our study, our aim was to compare chromosome heteromorphisms detected during routine cytogenetic analyses of infertile men. in this study, we aimed to assess the prevalence of such heteromorphisms and other constitutive chromosomal rearrangement among obese infertile and fertile groups.
For the current study, three different groups were included, non-obese infertile males (n= 100), obese infertile males (n= 100) and non-obese fertile males as controls (n= 100). all studies were performed in our routine cytogenetics laboratory. semen samples were collected from all study subjects and all semen parameters including liquefaction time, sperm count, motility, vitality etc, were analyzed according to who guidelines. peripheral blood samples were obtained from all participants (n = 300). chromosomes were harvested from 72 h lymphocyte cultures and giemsa-trypsin banding (g-banding) was performed. g-banded chromosomes were analyzed after harvesting and minimum 20 metaphases were analyzed for each case and heteromorphisms were reported according to iscn 2009.
No significant association of obesity with structural chromosomal rearrangement were observed between three groups under study
Non-syndromic obesity may not affect the fertility potential in men by increasing risk for chromosomal constitutive rearrangement.
Obesity; male infertility; chromosomal rearrangement; karyotype.