Isotretinoin Treatment for Autosomal Recessive Congenital Ichthyosis in a Golden Retriever

Abstract

Ichthyoses are hereditary cornification disorders that manifest with abnormal differentiation and desquamation of keratinocytes in a form of generalized dry and scaly skin. In golden retriever dogs, autosomal recessive congenital ichthyosis (ARCI) has been associated with mutations in the PNPLA 1 gene. In human medicine, isotretinoin is frequently used to treat ARCIs. The aim of this study was to investigate the clinical and histological effects of isotretinoin on ARCI in a golden retriever dog with confirmed mutation in the PNPLA 1 gene. Clinical examination, blood analysis and histopathological examinations were conducted before and after 90 days of isotretinoin therapy. The clinical and histopathological findings indicate that treatment with oral isotretinoin was effective in improving ichthyosis without any side-effects.

Keywords: PNPLA 1; autosomal recessive congenital ichthyosis; golden retriever; ichthyosis; isotretinoin.

Figure 1

Clinical response to isotretinoin therapy in a golden retriever dog with autosomal recessive congenital ichthyosis (ARCI). Pictures on the left were obtained before and those on the right after 3 months of treatment at the same body locations but on the contralateral sides. Picture before (a) and after treatment (b) on the trunk. Picture before (c) and after treatment (d), with clipped hair for better visualization of large white scales and latticelike hyperpigmentation (d). Picture before (e) and after treatment (f) in axillar region showing tan-to-yellow scales with variable hyperpigmentation.

Figure 2

Histopathological changes in skin biopsies in a golden retriever with autosomal recessive congenital ichthyosis (ARCI), before (a–c) and after treatment (d–f) with isotretinoin. Note the diffuse and severe laminar orthokeratotic hyperkeratosis in the stratum corneum in picture (a) (×4), (b) (×10) and (c) (×40). After treatment with isotretinoin, keratin was not so abundant, as shown in pictures (d) (×4), (e) (×10) and (f) (×40), and had a more typical basket-weave appearance (pictures e,f). In picture (c) (×40), there is a moderate number of scattered vacuolated keratinocytes (arrows) in the epidermis, while in picture (f) (×40), their number is decreased.