Congenital nail abnormalities: a review of the literature.

Congenital nail abnormalities (CNAs) are rare conditions in which the nail tissue appears abnormal compared with the fingers and the toes. They usually present accompanying deformities and disorders. Our purpose was to review the current literature on the clinical aspects of CNA. We reviewed the literature to evaluate peer-reviewed articles on the topic. Detailed reports have characterized many types of CNA. In this article, we provide a review of the literature based on the current understanding of CNAs and the clinical varieties thereof.