A novel chondroectodermal dysplasia mapped to chromosome 2q24.1-q31.1

Chondroectodermal dysplasias are genetically heterogeneous group of disorders involving defects in one or more ectodermal appendages (hair, nail, teeth and sweat glands) in association with anomalies of the cartilage. In the present study a novel form of chondroectodermal dysplasia, segregating in an autosomal recessive pattern in a Pakistani family, was investigated. The clinical features including proportionate short stature, osteopenia with fracturing and breaking of bones, hypodontia, hypertrophic and convex shaped nails, night blindness, watering eyes and infection of ears were observed in affected individuals of the family. Genetic linkage study mapped the novel autosomal recessive form of chondroectodermal dysplasia on human chromosome 2q24.1-q31.1. Linkage to the region was established by scanning human genome using Human Mapping 250K Nsp array. Linkage interval for chondroectodermal dysplasia on human chromosome 2q24.1-q31.1 spans 13.76 cM, which corresponds to 15.72 Mb according to the sequence-based physical map (Build 36.2). The maximum multipoint LOD score of 3.37 was obtained with several markers along the disease interval. Sequence analysis of three candidate genes (TANK, ITGB6, TBR1) located in the candidate interval did not discover potentially causal variants.