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Oculocutaneous Albinism Doberman Pinscher Type (OCA)
| Acronym: | OCA |
| Gene: | SLC45A2 |
| Mutation: | c.1442_*3934del |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Oculocutaneous Albinism Doberman Pinscher type (OCA) is an inherited disorder of melanin biosynthesis, phenotypically known as White Doberman Pinscher (WDP). OCA is characterized by a generalized reduction in hair, skin, and eye pigmentation. OCA, except for dogs, also affects humans, where this form of albinism is associated with numerous of other disorders; deafness, Hermansky-Pudlak, and Chediak-Higashi syndromes, and affected patients develop hemorrhage diathesis and dysfunctional immune system. All of these negative conditions have not been observed in white Doberman pinschers, they are not deaf, and do not develop bleeding diathesis or dysfunctional immune systems. The first white Doberman pinscher, Queen Sheba, was recorded by the American Kennel Club in 1976. Most of the white Doberman pinschers today have inherited the white genes from their ancestor Sheba, and all descendants of Sheba have a ‘’WZ’’ prefix on their registration numbers. However, since Sheba’s parents do not show close line breeding, Doberman pinschers who are not Sheba’s descendants could also carry the white genes.
The pigment within the coat is produced by the melanocytes, which are located in skin and hair but are also found in the inner ear, where they play an important role in ion transport control, which is crucial for the proper function of the inner ear. It has been shown that animals, in which melanocytes are not present in the inner ear, are deaf. However, OCA-affected Dobermann pinschers are not deaf. White Doberman pinschers 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 Doberman Pinscher Type (OCA) is caused by a deletion mutation in the SLC45A2 gene. SLC45A2 is a putative sugar transporter. The dysfunctional SLC45A2 gene results in an aberrant protein, which is necessary for protein sorting and enzymatic activity during melanogenesis. 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:
Winkler PA, Gornik KR, Ramsey DT, Dubielzig RR, Venta PJ, Petersen-Jones SM, Bartoe JT. A partial gene deletion of SLC45A2 causes oculocutaneous albinism in Doberman pinscher dogs. PLoS One. 2014 Mar 19;9(3). [PubMed: 24647637]