Congenital Onychodystrophy of the Index Fingers Clinical Presentation
- Author: Gregory J Raugi, MD, PhD; Chief Editor: William D James, MD more...
Congenital onychodystrophy of the index fingers is congenital.
Various nail abnormalities are observed, including (1) anonychia (lack of a fingernail), (2) micronychia (a small fingernail deviated to 1 side of the nail bed), (3) polyonychia (multiple, small, individual nails on one nail bed), (4) hemionychogryphosis (partial thickening and curvature of the fingernail), and (5) irregular lunula and nail malalignment. Appearance is displayed in the image below.
Micronychia is the most common clinical manifestation of congenital onychodystrophy of the index finger. This differs from the usual form of micronychia, which is located on the central part of the finger. In the micronychia of congenital onychodystrophy of the index finger, the onychodysplasia is deviated to the radial aspect of the involved digits. Additionally, most commonly, the index finger is involved, either unilaterally or bilaterally. Involvement of other fingers and toes is also reported. A 2008 case report describes a patient with congenital onychodystrophy of the index finger who had metacarpal bone abnormalities and no ring finger.
The true cause of congenital onychodystrophy of the index finger remains obscure. However, some evidence supports hereditary transmission. Also possible is an unidentified in utero exposure to teratogens in genetically predisposed individuals, allowing expression of congenital onychodystrophy of the index finger. See Differentials below for similar conditions and distinguishing features.
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