Prevalence of PNPLA1 Gene Mutation in 48 Breeding Golden Retriever Dogs

Abstract

A non-epidermolytic ichthyosis has been identified in Golden Retrievers due to a variant in the PNPLA1 gene, and a genetic test is available to detect wild-type, heterozygous and homozygous dogs. The aims of this study were to investigate the prevalence of the PNPLA1 gene variant in Golden Retrievers used for breeding and to provide more information to breeders in order to restrict the spread of this disease. Clinical examination and assessment of the PNPLA1 genotype using PCR testing of oral swabs were performed in 48 breeding Golden Retrievers. Wild-type, heterozygous or homozygous variants of the PNPLA1 gene were demonstrated in 10 (21%), 23 (48%), and 15 (31%) of the 48 dogs, respectively. In only 3 of the 48 dogs were clinical signs suggestive of ichthyosis identified. Data collected agreed with data reported in the literature. The high prevalence of homozygous and heterozygous variants makes the exclusion of mutated dogs from breeding impractical. Furthermore, the reliability of the PNPLA1 mutation in prediction of clinical signs of ichthyosis is unclear. Additional studies are needed to investigate if PNPLA1 is the only gene involved or if other genes and environmental factors have a role in the development of ichthyosis in Golden Retrievers.

Isotretinoin Treatment for Autosomal Recessive Congenital Ichthyosis in a Golden Retriever

“…Heterozygous dogs were found to be unaffected and able to transmit the PNPLA 1 variant to 50% of their lineage. Homozygous dogs were affected with clinical signs and it is known that they will transmit the PNPLA 1 variant to 100% of their lineage [ 4 , 10 ].…”

Ichthyosis in Dogs—Congenital Dermatologic Disorder

“…The formation of skin scales lasts for the whole life of the individual, but the disease may be manifested with a recurring exacerbation and/or remission. Secondary bacterial, mycotic or parasitic infections can be created and it may lead to pruritus [3,10,12,22,24].…”

“…The reliability of the PNPLA1 mutation in predicting clinical signs of ichthyosis in dogs is unclear. It is not yet known whether PNPLA1 is the only gene involved or whether other genes or environmental factors may play a role in the development of ichthyosis in Golden Retrievers [10]. In veterinary diagnostics, a genetic test by PCR using buccal swabs or whole blood is available to detect wild-type, heterozygous and homozygous dogs and helps to plan the right healthy breeding.…”

“…Several studies have been performed to determine PNP-LA1 mutation in Golden Retriever individuals. In the year 2018, G r a z i a n o et al [10] found that the prevalence of the PNPLA1 gene variant in Italian breeding programs was high and that only 21 % of the sampled dogs represented the wild-type. A study in Germany reported the result in puppies: 19 % of wild type, 53 % of heterozygous and 28 % of homozygous and in adult dogs it was similarly: 18 % of wild type, 47 % of heterozygous and 35 % of homozygous [30].…”

Genes of Congenital Dermatologic Disorders in Dogs—A Review

“…In the ma-jority of cases, autosomal recessive inheritance is involved and the simple Mendelian way of inheritance is applicable [17]. Congenital canine skin diseases include: primary seborrhoea, ichthyosis, hereditary nasal parakeratosis, dermatomyositis, colour dilution alopecia, skin mucinosis, dermoid sinus, lethal acrodermatitis, acral mutilation syndrome, keratoconjunctivitis sicca, ichthyosiform dermatosis, bullous epidermolysis, exfoliative dermal lupus erythematosus, congenital footpad hyperkeratosis and sebaceous adenitis [2,4,14,18,21,22,27,33,35,40,42,47,48,52].…”