Nail Disorder, Nonsyndromic Congenital, 9

Description

Although nails appear normal at birth, dystrophic changes develop within the first decade of life, resulting in onycholysis of fingernails and anonychia of toenails (summary by Rafiq et al., 2004). This disorder is referred to here as nonsyndromic congenital nail disorder-9 (NDNC9).

For a list of other nonsyndromic congenital nail disorders and a discussion of genetic heterogeneity, see NDNC1 (161050).

Clinical Features

Rafiq et al. (2004) reported a 6-generation consanguineous Pakistani family with autosomal recessive transmission of a form of hereditary nail dysplasia. Affected individuals had normal nails at birth, but onychodystrophy began at age 7 or 8 and resulted in anonychia of the toenails (complete absence of nails) and onycholysis of the fingernails (wide separation of nail from nail bed and dystrophy of free margins). Associated abnormalities of ectodermal appendages were not observed in any of the affected individuals.

Mapping

In a 6-generation consanguineous Pakistani family segregating autosomal recessive nail dysplasia, Rafiq et al. (2004) performed multipoint linkage analysis and obtained a maximum lod score of 4.85 at marker D17S1301. The authors stated that the gene for this form of nail dysplasia is probably contained within a 5.0-cM region of homozygosity flanked by markers D17S1807 and D17S937, corresponding to 17q25.1-25.3.