Autosomal recessive pure hair and nail ectodermal dysplasia linked to chromosome 12p11.1-q14.3 without KRTHB5 gene mutation

The study investigated a large consanguineous Pakistani family with four siblings affected by a congenital autosomal recessive form of hair-nail ectodermal dysplasia (HNED). Genetic linkage analysis identified a lod score of 2.92 at locus D12S368 on chromosome 12, suggesting the disease gene's location. Despite sequencing candidate genes, including KRTHB5 and four other keratin II genes, no mutations were found in the coding regions. The findings confirmed the linkage of this variant form of HNED to chromosome 12, indicating the possibility of a non-coding mutation in the KRTHB5 gene or a mutation in an unknown gene within the linked region.