Oculocutaneous Albinism Doberman Pinscher Type (OCA)
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 eyes’ pigmentation. OCA, except 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 haemorrhage diathesis and dysfunctional immune system. All of these negative conditions have not been observed in white Doberman pinschers, they are not deaf, do not develop bleeding diathesis or dysfunctional immune system. First white Doberman pinscher, Queen Sheba, was recorded by the American Kennel Club in 1976. Most of 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.
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 the ion transport control, which is crucial for 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 higher frequency of skin tumours and nevi, as well as photophobia and vision defects.
Oculocutaneous Albinism Doberman Pinscher Type (OCA) is caused by a deletion mutation in SLC45A2 gene. SLC45A2 is a putative sugar transporter. Dysfunctional SLC45A2 gene, results in an aberrant protein, which is necessary for protein sorting and enzymatic activity during melanogenesis.
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.
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]