Ichthyosis - Chihuahua

General description

The skin provides both an outward and inward barrier function, which is essential for survival. The skin undergoes a constant process of self-renewing. Stem cells are located in the basal layer of the epidermis, which differentiate into the horn-forming keratinocytes. These migrate to the uppermost layer of the epidermis, the stratum corneum, and form the keratin. Ichthyosis is a group of inherited cornification disorders with symptoms like dry skin, scaling, hyperkeratosis and erythroderma.

In the breed Chihuahua, a genetic variant of the SDR9C7 gene has been identified as potential cause of ichthyosis. This gene encodes for an enzyme that is involved in the production of the so-called corneocyte lipid envelope (CLE), a crucial component of the epidermal barrier. The affected dog showed typical symptoms of ichthyosis shortly after birth: abnormal scale formation all over the haircoat, moderate pruritus, mild erythema and malodorous skin. The genetic variant is inherited in an autosomal recessive manner.