Sperm DNA damage in non-familial sporadic heritable retinoblastoma (NFSHRb)

Abstract

Background/objectivesLoss of sperm DNA integrity hampers accurate transmission of genetic information to offspring, which may lead to childhood morbidity or even cancer. Sperm DNA damage (SDD) is chiefly oxidative in nature. Retinoblastoma (Rb) is the most common childhood cancer. The study was planned with an aim to analyze sperm DNA quality in the fathers of children with non-familial sporadic heritable retinoblastoma (NFSHRb) and determine if SDD may result in de novo germline RB1 mutations. Methods40 fathers of children with Rb and 30 controls were enrolled and categorized into 4 groups based on their social habits. Blood of parents and affected child was PCR amplified and sequenced to identify presence of any sequence variation in RB1 gene. Only those cases were enrolled where parents did not have somatic RB1 gene mutations; 20 children were heterozygous for RB1 gene mutation and 6 children did not harbour any somatic mutation. DFI, ROS and 8-OHdG were analyzed. ResultsSemen analysis showed no significant differences in cases and controls. Seminal mean ROS levels and mean DFI levels were significantly higher in cases as compared to controls (p<0.005*). ROS and DFI levels in smokers and alcohol users were higher as compared to non-smokers and alcohol non-users. ConclusionsOxidative SDD may lead to de novo germ line mutations and may be the underlying aetiology of NFSHRb. Oxidative damage to sperm DNA was observed in alcohol consumers and smokers and may increase incidence of Rb in this population subset. Thus poor lifestyle and social habits adversely affect paternal genome integrity.