SOAT1 Nonsense Variant in a Cat With Sebaceous Gland Dysplasia

We investigated a random-bred cat with sebaceous gland dysplasia. The cat presented with hypotrichosis and dark crusts on the skin. Histopathologically, sebaceous glands were enlarged and had an abnormal morphology with an increased number of undifferentiated reserve cells. Whole genome sequence analysis of the affected cat and comparison to 106 genomes of genetically diverse cats revealed a private homozygous nonsense variant in the functional candidate gene SOAT1 encoding sterol O-acyltransferase 1, XM_011291017.4:c.1221G>A or XP_011289319.1:p.(Trp407*). Based on the known role of SOAT1 in sebaceous gland function, the identified variant most likely represents the cause for the phenotype. To the best of our knowledge, we report the second pathogenic SOAT1 variant in cats. These results enable diagnostic genetic testing should any new cases come under veterinary care, detection of unaffected carrier animals, and strengthen the gene-phenotype relationship between SOAT1 and sebaceous gland dysplasias.