Deutsch
Hrvatski
Русский
Português
Oculocutaneous Albinism Lhasa Apso, Pekingese, Pomeranian Type (OCA)
| Acronym: | OCA, caL |
| Gene: | SLC45A2 |
| Mutation: | c.1478G>A |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Oculocutaneous Albinism Lhasa Apso, Pekingese, Pomeranian type is a form of albinism, a metabolic disorder affecting melanin production, affecting these breeds. There are two forms of albinism: Oculocutaneous Albinism, which affects the eyes and the skin, and ocular albinism (OA), where only the eyes are affected. The oculocutaneous albinism has been recorded in several breeds; Doberman pinscher, Leonberger, Rottweiler, Great Dane, German Spitz, Lhasa Apso, Pekingese, and Pomeranian, and in almost every breed, the disorder is caused by a different, breed-specific mutation. In several other species, including mice, humans, rabbits, cattle, and cats, albinism is associated with a mutation within the tyrosinase gene. Oculocutaneous Albinism in Lhasa Apso, Pekingese, and Pomeranian is displayed as hypopigmentation in skin, hair, and eyes. Affected dogs have pale irises and pink noses and lips. Multiple reports show a higher frequency of skin tumors and nevi, as well as photophobia and vision defects.
Oculocutaneous Albinism Lhasa Apso, Pekingese, Pomeranian Type is caused by a substitution mutation in the SLC45A2 gene. The SLC45A2 gene codes for protein located in melanocytes. The exact function of this protein is not known, but it is likely involved in the production of melanin, by taking part in transport molecules crucial for the normal function of melanosomes. The disorder is inherited in an autosomal recessive pattern. Healthy parents of an affected dog are obligate heterozygotes and therefore carry one mutant allele. Heterozygotes are carriers and show no symptoms. At conception, each cub has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier.
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:
Wijesena H. R., Schmutz S. M. (2015): A Missense Mutation in SLC45A2 Is Associated with Albinism in Several Small Long Haired Dog Breeds. Journal of Heredity, 2015, 285–288.