Identification of a genetic locus for ichthyosis vulgaris on chromosome 10q22.3-q24.2.

Ichthyosis vulgaris (IV) is one of the most commonly inherited disorders and has an estimated prevalence rate of 2.29% in China. To date, only one gene responsible for IV, the filaggrin gene (FLG), was identified, but genetic heterogeneity exists. In this study, two Chinese families with autosomal-dominant IV were genetically characterized. The FLG gene was first excluded as the disease-causing gene in the two families. The larger family was then characterized by genome-wide linkage analysis to identify a new genetic locus for IV. Significant linkage was identified with markers on chromosome 10q22.3-q24.2 with a maximum LOD score of 3.19. No other markers showed a LOD score of >1.5. Fine mapping defined the new genetic locus within a 20.7 cM region between markers D10S569 and D10S1709. The second family also showed positive linkage to the same 10q22.3-q24.2 region. The combined maximum LOD score in the two families was 3.95. Identification of linkage in two independent families provides strong genetic evidence that a previously unreported gene for IV is located on chromosome 10q22.3-q24.2. Future studies of the candidate genes at the 10q IV locus will identify a specific gene, which will provide insights into the pathogenesis of IV.