Genetic factors and clinical significance of acanthosis nigricans in obese Japanese children and adolescents.

To clarify the clinical significance of acanthosis nigricans (AN) and the association of gene polymorphisms in the ss2- and ss3-adrenergic receptors (B2ADR and B3ADR) in Japanese obese children and adolescents.Seventy obese subjects (56 boys, 14 girls) from 5 to 19 y of age were examined as to clinical features. Genetic analyses were performed in 83 obese subjects (61 boys, 22 girls), 2 to 17 y of age. Typing of gene polymorphisms in B2ADR and B3ADR was achieved by polymerase chain reaction (PCR) of genomic DNA and restriction fragment-length polymorphism analysis (PCR-RFLP).The group with AN (n = 30) had higher values for percent overweight, BMI, waist circumference, fasting insulin, HOMA-R, leptin and PAI-1 than the AN-negative group (n = 40), but there were no significant differences in age, sex or percent body fat between the two groups. The prevalences of B2ADR Gly16 and B3ADR Arg64 were significantly higher in AN-positive (n = 26) than in AN-negative (n = 57) subjects. In addition, the AN frequency was significantly higher in the group with both Gly16 and Arg64 than in the group with neither of these alleles (55.6% vs 12.5%, p < 0.05).We demonstrate that AN is a useful clinical marker for the severity of obesity associated with a high BMI, and that B2ADR Gly16 and B3ADR Arg64 are associated synergistically with AN in obese children and adolescents.