The role of androgen receptor gene in cyclosporine induced gingival overgrowth.

BACKGROUND AND OBJECTIVE: Gingival overgrowth is a prominent side effect of cyclosporine (CsA) therapy in renal transplant patients. Although the exact mechanism by which this drug induces gingival overgrowth is uncertain, marked variations in individual susceptibility to this drug suggest a genetic predisposition. Studies have shown that genetic variation (polymorphism) in the trinucleotide cytosine-adenine- guanine (CAG) sequence in exon 1 of the androgen receptor (AR) gene is related to altered activity of the AR as a transcription factor. However, the relationship between the length of the CAG repeat and gingival overgrowth has not yet been studied. The present study was carried out to determine whether there is an association between CsA-induced gingival overgrowth and the length of the CAG repeats in the AR gene. MATERIAL AND METHODS: Genomic DNA samples were prepared from the blood of 50 renal transplant patients with CsA-induced gingival overgrowth and from the blood of 100 renal transplant patients on CsA with no gingival overgrowth. RESULTS: The difference in allele distribution among the subjects with gingival overgrowth and control samples was statistically significant (p = 0.001). CONCLUSION: The findings suggest a link between CsA7induced gingival overgrowth and a smaller size of CAG repeat in the AR gene.