Abstract

Persons chronically exposed to environmental arsenic through their drinking water experience various arsenic induced clinical manifestations which includes keratosis and pigmentary changes in the skin. However the response varies widely among persons. To study whether Glutathione-S-Transferase (GST) gene polymorphism plays any role in this variation, a total of 78 study subjects were recruited from the villages of southern region of West Bengal, India. Concentration of arsenic in their urine and drinking water were determined by Atomic Absorption Spectrophotometry Hydride Generation (AAS) system. Extent of clinical manifestations in the form of pigmentation and keratosis were determined by evaluation of the severity and giving clinical symptom score according to their degree of severity. The individual’s GST status was determined by multiplex PCR approach. The persons having skin manifestation given a score called clinical symptom score by which the degree of the clinical manifestation was determined. Results showed that genetic polymorphism of GSTM1 and T1 were significantly associated with urinary arsenic and clinical manifestation in higher exposure group. Persons having null genotype have significantly decreased urinary arsenic (p< 0.01) and increased clinical symptom (p<0.05) score relative to persons with GSTM1 or GST T1 non-null genotype of same arsenic exposure group. The study signifies that GST status determines the extent of biotransformation of arsenic in the body which further determines the degree of arsenic induced clinical manifestations in exposed persons.

Key words: Arsenic, GST polymorphism, total urinary arsenic, clinical symptom score.