In 1976, a 'white' Doberman Pinscher was whelped and was subsequently bred to her son, who was also bred to his litter sisters. This tight inbreeding continued for some time to allow the breeders to 'fix' the mutation. White Dobermanns are a cream color with white markings and blue eyes. Although this is consistent with albinism, the proper characterization of the mutation is currently unknown. The animals are commonly known as tyrosinase-positive albinoids, lacking melanin in oculocutaneous structures. This condition is caused by a partial deletion in the SLC45A2 gene. cervical vertebral instability (CVI), von Willebrand's disease (a bleeding disorder for which genetic testing has been available since 2000), and prostatic disease. Less serious common health concerns include hypothyroidism and hip dysplasia. Canine compulsive disorder is also common. Studies have shown that the Doberman Pinscher suffers from prostatic diseases, (such as bacterial prostatiti, prostatic cysts, prostatic adenocarcinoma, and benign hyperplasia) more than any other breed.