CONGENITAL ONYCHODYSPLASIA OF THE INDEX FINGERS - ISO-KIKUCHI-SYNDROME - A CASE INVOLVING THE 2ND TOENAIL

We report a case of congenital onychodysplasia of the index fingers (I so-Kikuchi syndrome) in a 2-year-old boy who had nail deformities on b oth index fingers and the left second toe. He had a micronychia of the left index fingernail, malalignment and abnormal lunula of the right index fingernail and micronychia and malalignment of the left second t oenail. Congenital onychodysplasia of the index fingers (COIF) is a ra re condition characterized by various forms of nail dysplasia commonly involving the index fingers, but not infrequently also the neighbouri ng fingers such as the middle fingers and thumbs. The five criteria ch aracterizing COIF include the following: (i) congenital occurrence; (i i) unilateral or bilateral index finger involvement; (iii) variability in nail appearance; (iv) possible hereditary involvement; and (v) fre quently associated bone abnormalities. The nails of COIF include the f ull spectrum of nail dysplasia, from an irregular lunula, malalignment , micronychia (hypoplastic and rudimental), polyonychia (split rudimen tal), and anonychia, specifically affecting the index fingers. Our pat ient represents various forms of nail dysplasia of the both index fing ers and left second toe such as micronychia, malalignment and abnormal lunula. To our knowledge, the association with second toenail dysplas ia in COIF has not previously been reported.