METACARPOPHALANGEAL PATTERN PROFILE ANALYSIS IN WILLIAMS-SYNDROME

Many patients with Williams syndrome (WS) are not diagnosed until they are old enough to demonstrate the characteristic personality and faci al changes. A number of these changes are quite subtle and none of the m is present in all affected individuals. The cause of WS remains obsc ure and consequently, there are no cytogenetic, biochemical, or molecu lar studies to help in the diagnosis of patients in whom the diagnosis is uncertain. We have generated a mean WS metacarpophalangeal pattern profile (MCPP) on 21 clinically diagnosed individuals with WS. This m ean syndrome profile shows that WS hands are smaller than average age- matched control hands and that the distal phalanx of the thumb is disp roportionately large with respect to the rest of the hand. A mathemati cal model, which effectively discriminates WS patients from unaffected control individuals, was developed using discriminant analysis of the MCPP data. Of the 21 WS patients classified by this method, only 2 we re misclassified as ''normal.'' Similarly, 2 of the 24 control individ uals were misclassified as ''WS,'' yielding an overall successful clas sification rate of 91%. (C) 1993 Wiley-Liss, Inc.