Heterozygous Deletion of the NSDHL Gene in an Appenzeller Mountain Dog with Verrucous Epidermal Keratinocytic Nevi

A 10-month-old female Appenzeller Mountain Dog exhibited severe hyperkeratosis and alopecia due to a heterozygous deletion of the NSDHL gene, identified through whole-genome sequencing. This genetic defect, which disrupts cholesterol biosynthesis, was not detected by Sanger sequencing. The dog's condition improved with oral ketoconazole, highlighting the importance of advanced genomic analysis in diagnosing structural variants. The study emphasizes the role of de novo mutations in genetic disorders and the potential for therapeutic intervention by reducing cholesterol precursors.