Ichthyosis (type American Bulldog)

 

Gene: NIPAL4

Transmission: Autosomal, recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease. Both parents of an affected animal must be carriers of at least one copy of the mutation. Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Deletion, NIPAL4 gene; c.744 del.C, p.(I249 STOP)

Medical system: Skin

Breeds: American Bulldog, American Staffordshire Terrier/Amstaff, Boxer, English Bulldog, French Bulldog, Labrador Retriever, American Bully

Age of onset of symptoms: 1 to 2 weeks of age

Ichthyosis refers to a family of skin diseases that disrupt normal skin structure and function and give a scaly appearance of the skin. “Ichthy-” refers to fish, as in fish scales. Ichthyosis is a very common condition in the canine population with both genetic and environmental contributing factors. Ichthyosis of the American Bulldog is caused by a mutation of the NIPAL4 gene, which codes for a protein found in the skin. Without this protein, the skin has a cornification disorder which weakens the barrier that protects against microbes as well as environmental and chemical products. Increased desquamation is a direct consequence of this disorder. The hair coat of the affected animal has a disheveled appearance with generalized soft white scales. Skin without hair has a brownish discoloration with redness and adherent scales. Affected dogs often have a yeast infection associated with itching. There is no definitive treatment for ichthyosis but it can be managed by topical drugs, hydrating creams and anti-yeast treatments.

 

References:

OMIA link: [1980-9615]

Donner J, Freyer J, Davison S, et al. (2023) Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs.  PLoS Genet. 19(2):e1010651. [pubmed/36848397]

Mauldin EA, Elias PM. (2021) Ichthyosis and hereditary cornification disorders in dogs. Vet Dermatol 32:567-e154. [pubmed/34796560]

Briand A, Cochet-Faivre N, Reyes-Gomez E, et al. (2019) NIPAL4 deletion identified in an American Bully with autosomal recessive congenital ichthyosis and response to topical therapy. Vet Med Sci 5(2):112-117 [pubmed/30741495]

Casal ML, Wang P, Mauldin EA, Lin G, Henthorn PS. (2017) A Defect in NIPAL4 Is Associated with Autosomal Recessive Congenital Ichthyosis in American Bulldogs. PLoS One 12(1):e0170708. [pubmed/28122049]

Mauldin EA, Wang P, Evans E, et al. (2015) Autosomal Recessive Congenital Ichthyosis in American Bulldogs Is Associated With NIPAL4 (ICHTHYIN) Deficiency. Vet Pathol. 52(4):654-62. [pubmed/25322746]

 

Contributed by: Marine Rullier, Class of 2020, Faculty of Veterinary Medicine, University of Montréal.