Evaluation of the CTSL2 gene as a candidate gene for alopecia X in Pomeranians and Keeshonden

Alopecia X is a noninflammatory, progressive, bilateral symmetric alopecia in dogs. The disease is mainly found in Nordic breeds. The breed predisposition and a strong familial accumulation suggest a hereditary background. We analyzed the cathepsin L2 gene (CTSL2) as a candidate for alopecia X. The comparative sequencing of 14 affected and 18 control animals revealed ten polymorphisms; however, none of these polymorphisms affected the coding sequence. Haplotype analysis did not reveal an association of one particular CTSL2 haplotype with the disease phenotype; therefore, we conclude that the CTSL2 gene is probably not the causative gene for alopecia X.