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Dog Ichthyosis (ICT)
| Acronym: | ICT |
| Gene: | PNPLA1 |
| Mutation: | c.1445_1447delinsTACTACTA |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Dog ichthyosis is a hereditary, monogenic, cornification disorder, appearing early and persisting for life. Cornification disorders form a heterogeneous group of diseases characterized by abnormal differentiation (cornification) of the epidermis. The ichthyoses, diseases in this group, are distinguishable clinically by generalized scaling and histopathologically, in most cases, by a thickened stratum corneum. In veterinary medicine, ichthyosis is now commonly classified into either epidermolytic or non-epidermolytic subtypes. Most reported cases in dogs are non-epidermolytic with heterogeneous clinical, histopathological, and ultrastructural profiles.
In golden retrievers, hereditary non-epidermolytic retention ichthyosis was diagnosed and described for the first time in 2007. More recently, the clinical, epidemiological, and histopathological characteristics of this disease have been precisely analyzed, and an autosomal recessive transmission mode has been proposed. Dermatological signs, visible as early as a few weeks of age, include a mild, moderate, or severe generalized scaling, initially with small to large whitish scales and progressively with blackish scales. Ichthyosis in the golden retriever has recently spread throughout the breed because of the repeated use of champions and inbred crosses with affected or carrier dogs. Since the vital prognosis was not engaged, the disease has not been counter-selected and has thus rapidly spread throughout the breed with the frequency of the mutation now reaching 50%.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Grall, A., Guaguère, E., Planchais, S., Grond, S., Bourrat, E., Hausser, I., Hitte, C., Le Gallo, M., Derbois, C., Kim, G.-J., et al. (2012). PNPLA1 mutations cause autosomal recessive congenital ichthyosis in golden retriever dogs and humans. Nat Genet 44, 140–147.
Gross, T.L., Ihrke, P.J., Walder, E.J. & Affolter, V.K. (2005): Chapter 8: Diseases with abnormal cornification. 2.nd edt. In: T.L. Gross (ed.): Skin Diseases of the Dog and Cat: Clinical and Histopathological Diagnosis. Blackwell Science Ltd, UK, pp. 161-198.
Guaguere, E., Bensignor, E., Küry, S., Degorce-Rubiales, F., Muller, A., Herbin, L., Fontaine, J., and André, C. (2009). Clinical, histopathological and genetic data of ichthyosis in the golden retriever: a prospective study. J Small Anim Pract 50, 227–235.