Rapid detection of homozygous mutations in congenital recessive ichthyosis.

Congenital recessive ichthyoses (CRI) form a remarkably heterogeneous group of diseases, resulting from mutations in at least eight distinct genes, six of which have been identified so far. In the present study we ascertained two CRI families of Iranian and Druze origins. Exploiting the high degree of consanguinity characterizing these populations, we typed all family members for microsatellite markers spanning the major CRI chromosomal loci and used homozygosity mapping to identify candidate genes for subsequent mutational analysis. This strategy led to the rapid identification of two novel homozygous CRI-causing mutations in TGM1 (c.2058delC) and FLJ39501 (p.W521X). The present data demonstrate that the molecular analyses of CRI in consanguineous families can be readily completed in less than 96 h at relatively low costs.