Hypotrichosis 2 (HR gene, Lykoi)

Hypotrichosis in Lykoi cats has been linked to the HR gene and is characterized by a significant reduction in the number of hair follicles, resulting in a sparse or partial coat.

Definition

Lykoi cats have hypotrichosis due to variants in the HR (hairless) gene. The HR gene is responsible for ensuring a normal cycle of growth and renewal of hair follicles, so its alteration results in hair growth problems. Hypotrichosis reduces the number of hair follicles and causes a "roaning" effect, which is a mixture of colored hairs and white hairs. In addition, the undercoat is sparse and the follicles are smaller and more deformed than normal.

Genetic basis

In this study, we focus on a complex mutation involving an insertion together with a deletion (hr^Fr allele) in the HR gene. This variant has an autosomal recessive inheritance, meaning that two copies of the mutation are required for the phenotype to be expressed. However, the presence of a single copy can be transmitted to offspring with a 50% probability. In addition, the trait can also manifest in individuals with compound heterozygosis, i.e. those who carry a copy of two different variants in the HR gene. Cases of compound heterozygosity of the hr^TN and hr^VA alleles have been reported.

Other relevant information

Hypotrichosis, responsible for the distinctive appearance of Lykoi cats with their sparse coat and mixture of colored and white hairs, has earned them the nickname "wolf cats".

Bibliography

Buckley RM, Gandolfi B, Creighton EK, et al. Werewolf, There Wolf: Variants in Hairless Associated with Hypotrichia and Roaning in the Lykoi Cat Breed. Genes (Basel). 2020