A genome-wide association study for canine cryptorchidism in Siberian Huskies

Cryptorchidism is a condition whereby one or both testes fail to descend into the scrotal sac. Here, we performed a genome-wide association study (GWAS) with both a case-control analysis using the GEMMA software accounting for population structure and a BayesB approach in the GenSel software applied to every 1 Mb window of SNPs or haplotypes. The haplotypes were constructed from a genealogical tree using the population of 204 Siberian Huskies. The BayesB analyses identified six putative genomic candidate regions on CFA6, 9, 24, 27 and X. These regions explained a high percentage of genetic variance when compared with other genomic regions. The positional candidate genes Q9TSI5_CANFA (matrix metalloproteinase 9 precursor) on CFA24, ADAMTS20 (ADAM metallopeptidase with thrombospondin type 1 motif, 20) on CFA27 and MID1IP1 (MID1 interacting protein 1) on CFAX are known to be functionally related to extracellular matrix remodelling, which might be important for gubernaculum elongation and thus interrupting normal testicular descent. Further mutation screening in these candidate regions on CFA6, 9, 24, 27 and X is needed. Next generation sequencing will help to uncover rare variants associated with cryptorchidism in this dog population.