METACARPOPHALANGEAL PATTERN (MCPP) PROFILE ANALYSIS IN A FAMILY WITH TRIPHALANGEAL THUMB

Triphalangeal thumb (TPT) is a rare congenital disorder characterised by a long, finger-like thumb with three phalanges instead of two. It c an occur as an isolated defect, in association with other abnormalitie s of the hands and feet, or as a part of a syndrome. Sporadic cases ha ve been described, but it is usually inherited as an autosomal dominan t trait. In order to examine skeletal morphology in different phenotyp ic variations of this disorder, we performed metacarpophalangeal patte rn profile analysis in one kindred with this disorder. A characteristi c profile occurred in all affected people, based on the individual len gthening or shortening of the thumb bones. Comparison of the affected and unaffected people from this family with people with a different ge netic background suggests that the described profile is specific for T PT and could be used as a helpful diagnostic tool in syndromes which i nclude TPT.