Congenital eye malformation / microphthalmos (SIX6-related) - Golden Retriever

What does this test detect?

This genetic test analyses the SIX6 variant c.487C>T for congenital eye malformation in Golden Retrievers.

Other names for this condition

The condition is also described as congenital eye malformation, congenital ocular malformation, microphthalmos, SIX6-related eye malformation or MOD-SIX6.

What does this mean for the dog?

SIX6 is a developmental gene important for eye formation. Dogs with the variant may develop a wide range of congenital eye defects, including visual impairment, nystagmus, cataract, retinal detachment, abnormalities of the lens, cornea or retina and microphthalmos. One or both eyes may be affected and severity can vary strongly between dogs.

Inheritance and result

The variant acts as autosomal dominant with incomplete penetrance. One copy can be enough to strongly increase the risk of eye malformation, but not every dog with the variant shows the same visible abnormalities. Two copies are rare and require careful interpretation, but genetically this means the dog can pass only the variant allele.

Practical value of this test

• The test helps breeders identify variant-positive dogs before breeding combinations are chosen.
• The result supports selection to limit spread of a dominant eye variant within a line.
• In puppies or relatives with eye abnormalities, the test provides genetic clarity about a SIX6-related cause.
• Because penetrance and severity can vary, DNA information helps include apparently normal carriers in breeding plans.