[A boy with digital clubbing].

A 4-year-old boy was referred because of pan-digital clubbing and watch-glass nails. Other remarkable findings were: surgical closure of a patent arterial duct, decreased knee-mobility and consanguineous parents. This combination is suggestive for primary hypertrophic osteoarthropathy (PHO; #OMIM 259100). PHO was proven by his homozygous mutation of the 15-hydroxyprostaglandine dehydroxygenase-gene.