Ichthyosis (type Jack Russell Terrier)

 

Gene: TGM1

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: Insertion, TMG1 gene; ins.1980bp LINE-1, intron9

Medical system: Skin

Breeds: Jack Russell Terrier, Parson Russell Terrier, Russell Terrier, Shih Tzu

Age of onset of symptoms: From birth, progressive with age

Ichthyosis refers to a family of skin diseases that disrupt normal skin structure and function and give a scaly appearance to 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.  Jack Russell Terrier-type ichthyosis is non-epidermolytic, meaning that blisters are not associated with it.  Due to the lack of activity of an enzyme, the skin of affected dogs is thicker and duller than normal.  Whitish to greyish greasy scales are present all over the body.  The diagnosis can be made by performing a biopsy.  There is no curative treatment, but if the condition is not severe, it is possible to use shampoos to control the clinical signs.  Affected animals are often euthanized due to a poor quality of life.

 

References:

OMIA link: [0546-9615]

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

Mauldin EA. (2013) Canine ichthyosis and related disorders of cornification.  Vet Clin North Am Small Anima Pract. 43(1):89-97. [pubmed/23182326]

Credille KM, Minor JS, Barnhart KF, et al. (2009) Transglutaminase 1-deficient recessive lamellar ichthyosis associated with a LINE-1 insertion in Jack Russell terrier dogs. British Journal of Dermatology 161:265-272. [pubmed/19438474]