Peculiar facial appearance and generalized brachydactyly in a patient withcongenital onychodysplasia of the index fingers (Iso-Kikuchi syndrome)

We report on a patient with clinical manifestations consistent with a diagn osis of congenital onychodysplasia of the index fingers (COIF), This syndro me has been found mainly in Japan, and as far as we know, this is the first case reported in Italy. In addition to the typical bilateral split nail of the second finger, the patient showed bilateral inguinal hernia, a peculia r face, and short hands. The metacarpophalangeal profile showed a generaliz ed brachydactyly with all the hand long bones below x 3 SD. The patient's f ather showed a peculiar kind of micronychia on both the fifth toes, suggest ing a possible autosomal dominant transmission of the syndrome. In utero is chemia of the palmer digital artery and a dysplastic change in the crescent -shaped cap of the distal phalanx are the two main candidate pathogenetic m echanisms that have been proposed. In our opinion, the gradual broadening o f the spectrum of this syndrome brings support to the hypothesis of a basal dysplastic pathogenetic mechanism involving not only the index fingers but also perhaps other tissues outside. We think that for the moment the defin ition of COIF for this syndrome should be maintained, the alternative propo sed term "congenital onychodysplasia" being too indefinite. (C) 2001 Wiley- Liss, Inc.