congenital onychodysplasia of the index fingers congenital onychodysplasia of the index fingers congenital onychodysplasia of the index fingers is defined by the presence of the condition at birth, either unilateral or bilateral index finger involvement, variable distortion of the nail or lunula, and polyonychia, micronychia, anonychia, hemi-onychogryphosis, or malalignment. the original paper was kikuchi i, horikawa s, amano f (november 1974). "congenital onychodysplasia of the index fingers". arch dermatol. 110 (5): 743–6. doi:10.1001/archderm.1974.01630110037008. pmid 4419705. this condition is also called iso-kikuchi syndrome, since iso was the first author who published it in a japanese paper.