Mercury toxicity and DNA damage in patients with Down syndrome

Abstract

Objective The aim of the present study was to examine the relationship between exposure to mercury and DNA damage in children with Down syndrome (DS). Patients and methods Ninety-five Egyptian patients clinically diagnosed and cytogenetically proved to have nondisjunction trisomy 21 and 90 Egyptian healthy controls were recruited from the outpatient clinic of the Clinical Genetics Department, National Research Centre, Egypt. DNA damage was determined using the alkaline comet assay. Serum mercury levels were determined using an atomic absorption spectrophotometer. Results Mercury levels were significantly elevated in the DS group (mean±SE 126.6±9) compared with the control group (72±2) (P≤0.05); moreover, there was a significant increase in the DNA damage levels in the DS group (60.6±5.7) compared with the control group (3.2±0.5) (P≤0.05). Pearson’s correlation results showed positive significant correlation between mercury levels and DNA damage levels in DS patients (P≤0.05). Conclusion Our study suggested that mercury intoxication as well as oxidative stress may be biomarkers of toxicity in patients with DS.