Nail-patella syndrome: an incidental finding from abdominal discomfort.

An otherwise healthy 18-year-old woman had abdominal discomfort. Physical examination and laboratory studies were unremarkable, with the exception of nail dystrophy of the ulnar digits. An abdominal plain film revealed bilateral posterior iliac horns, pathognomonic of nail-patella syndrome. Additional radiographs showed hypoplastic patellas bilaterally. While glomerulonephritis occurs in 30% of patients with nail-patella syndrome, there was no evidence of renal involvement.