A mutation in RBP4 gene causes misfolding of RBP protein and subsequently disruption of vitamin A transport from maternal hepatic stores to the placenta and the developing foetal eye. This only occurs if homozygous mutation in RBP4 gene is present in both the mother and the offspring. The consequence of this mutation leads to severe congenital eye malformations in Irish soft-coated wheaten terriers. Dogs suffer from bilateral microphthalmia a congenital condition (present at birth) in which dogs have very small eyes and anatomical defects, resulting in incurable blindness.

Inheritance: autosomal recessive

Mutation: RBP4 gene

Genetic test: The method used for testing is extremely accurate and allows complete differentiation between affected animals, carriers and healthy dogs. Testing can be done at any age.

Sample: EDTA whole blood (1.0 ml) or buccal swabs. Detailed information about sampling can be found here.