DNA Damage Analysis in Children with Non-syndromic Developmental Delay by Comet Assay

Abstract

Introduction: Majority of the developmental delays in children are non-syndromic and they are believed to have an underlying DNA damage, though not well substantiated. Hence the present study was carried out to find out if there is any increased DNA damage in children with non-syndromic developmental delay by using the comet assay. Aim: The present case-control study was undertaken to assess the level of DNA damage in children with non syndromic developmental delay and compare the same with that of age and sex matched controls using submarine gel electrophoresis (Comet Assay). Materials and Methods: The blood from clinically diagnosed children with non syndromic developmental delay and controls were subjected for alkaline version of comet assay – Single cell gel electrophoresis using lymphocytes isolated from the peripheral blood. The comets were observed under a bright field microscope; photocaptured and scored using the Image J image quantification software. Comet parameters were compared between the cases and controls and statistical analysis and interpretation of results was done using the statistical software SPSS version 20. Results: The mean comet tail length in cases and control was 20.77+7.659μm and 08.97+4.398μm respectively which was statistically significant (p<0.001). Other comet parameters like total comet length and % DNA in tail also showed a statistically significant difference (p < 0.001) between cases and controls. Conclusion: The current investigation unraveled increased levels of DNA damage in children with non syndromic developmental delay when compared to the controls.

Keywords

• damage to deoxy-ribonucleic acid
• delayed development
• gel electrophrosis
• malonyldialdehyde