Friday, July 6, 2018
Blinding canine eye disease.Discovery for a blinding canine eye disease reveals an unprecedented mode of inheritance.A new gene for canine congenital eye disease has been identified. Defective RBP4 leads to vitamin A deficiency and abnormal eye development during pregnancy. The study defines a novel recessive mode of maternal inheritance, which may underlie other types of birth defects. Collaborating research groups from the University of Helsinki, UC Davis and the University of Jyväskylä describe a new genetic cause for canine congenital eye disease in Irish Soft-Coated Wheaten Terriers. The affected dogs suffer from bilateral microphthalmia i.e. very small eyes and anatomical defects, resulting in incurable blindness. Similar findings are seen in the Microphthalmia-Anophthalmia-Coloboma (MAC) spectrum of human congenital eye malformations, which are important causes of childhood blindness. RBP4 defect leads to vitamin A deficiency -- a known risk factor for eye diseases. The study demonstrates a novel recessive mode of genetic inheritance, which has not described before. The researchers discovered that the dam's genotype determines the puppy's disease risk as both the dam and puppy must be homozygous for the mutation to manifest the disease.As a part of the research, a DNA test has been developed for veterinary diagnosis and breeding purposes. DNA testing is important for breeders to avoid producing more blind dogs. The test can identify carriers and allow better breeding plans.