PCR-RFLP molecular confirmation of color dilution alopecia in dogs in Brazil.

Color dilution alopecia (CDA) is a dermatopathy observed exclusively in animals having a diluted coat color. In dogs, color dilution occurs as a result of a single-nucleotide variation (SNV) c.-22G > A in the melanophilin gene. We standardized a PCR-restriction-fragment length polymorphism (PCR-RFLP) technique to identify this mutation and determine its frequency in dogs in Brazil. The standardized PCR-RFLP technique could efficiently identify the SNV c.-22G > A in the melanophilin gene, with mutated allele frequencies of 0.1, 0.1, and 0.0875 in Dachshund, Miniature Pinscher, and Yorkshire Terrier breeds, respectively, with no statistical difference among the breeds (p = 0.252). The mutation was identified in 2 homozygous Dachshund dogs with alopecia, confirming the clinical characteristic of CDA. The standardization of a simpler and more accessible molecular technique for recognition of the SNV c.-22G > A in the melanophilin gene allows identification of heterozygous (phenotypically normal) dogs that can be excluded from reproduction, to avoid the birth of dogs with diluted coat color and consequently CDA.