Klippel–Trenaunay syndrome is easily diagnosed at birth but sometimes slips past doctors, according to Indian dermatologists who found the rare genetic condition in a three-year-old boy.

First reported in 1900, the disorder — also known as hemangiectatic hypertrophy syndrome or angio-osteohypertrophy syndrome — has unknown aetiology, with no clear racial or sex associations, said doctors from Datta Meghe Medical College in Nagpur.