Malformations of the index nails

Abstract

We report a 52-year-old woman with micronychia of the index fingers. Radiographic examination revealed a Y-shaped bifurcation of the distal phalanx of both index fingers. She was diagnosed with congenital onychodysplasia of the index fingers (COIF) or Iso-Kikuchi syndrome. COIF is a rare condition characterized by a variety of nail dysplasia of the index fingers. Five criteria characterize COIF: congenital occurrence, unilateral or bilateral index finger involvement, variability in nail appearance, hereditary involvement and frequently associated bone abnormalities. Micronychia, polyonychia, anonychia, hemionychrogryphosis and malalignment are the observed index finger defects. Most cases have been described in Japan, and to our knowledge, this is the first case of COIF reported in South America.

Iso-Kikuchi Syndrome in A Newborn and His Mother

“…International incidence is about 4.2/100000 births [3]. It was first reported in Japan, and later in other countries such as the USA, England, France, Korea [5], Argentina [1], Brazil [7] and Italy [3,5,8]. It affects primarily the nails of the index fingers, especially the medial aspect of the nail and it can also affect the underlying bone [1][2][3][4]8].…”

“…Anomalies include: polyonychiawhere there are two small incomplete nails on one finger with the lateral one being larger than its counterpart-, micronychiawhere a small nail is seen in the lateral aspect of the finger, anonychia -meaning the total absence of the nail-, hemionychogryphosis, alterations of the lunula [2] and misalignment [1,4,5,7,[9][10][11].…”

“…Years later, in 1980, Baran and Stroud suggested a modification of the criteria: congenital occurrence, unilateral or bilateral index finger involvement, variability in nail appearance, possible hereditary involvement and frequently associated bone abnormalities [1,3,4,7,8,11].…”

“…The pathogenesis is unknown; some authors suggest a genetic abnormality or ischemia during the fetal period. A complete family history is important to determine if it is a sporadic or a hereditary condition [6][7].…”

A Case of Cutis Marmorata Telangiectatica Congenita with Onychodysplasia

“…COIF는 1984년 Baran 과 Stroud에 의해 진단 기준이 개정되었으며 다음 5가지로 특 징지어진다; (1) 선천 발생(congenital occurrence), (2) 일측 또는 양 측 인지 포함(unilateral or bilateral index finger involvement), (3) 손톱 형태의 다양성(variability in nail appearance), (4) 유전 가능성 (possible hereditary involvement), (5) 골 기형 관련 빈도 (frequently associated bone anomalies) 15) . 병인은 정확히 밝혀지 지 않았지만 유전 또는 태아기 손가락의 허혈이 가설로 제기되고 있 다 16) . 본 증례에서 환아는 위 기준에서 유전 가능성을 제외한 나머 지 4가지에 모두 해당하였다.…”