Multiocular Defect / MOD (COL11A1-related) - Old English Sheepdog

What does this test examine?

This genetic test analyses the COL11A1 c.1775T>C variant in the Old English Sheepdog. The condition is known as multiocular defect, Multiocular Defect, MOD and COL11A1-related inherited eye disease.

COL11A1 encodes a collagen protein that is important for connective tissue and eye structures. The c.1775T>C variant alters the protein and causes an inherited ocular syndrome in this breed, with several parts of the eye potentially involved.

What does this condition mean?

MOD can combine several eye abnormalities. Reported features include cataract, lens and vitreous changes, enlarged eyes, coloboma, retinal detachment, intraocular inflammation, increased eye pressure and loss of vision. Severity can vary between dogs: some animals show relatively mild abnormalities, while others develop clear visual impairment or painful complications.

Inheritance and result

The trait is inherited as autosomal dominant. One copy of the COL11A1 variant is enough to cause MOD risk. A dog with two copies is also positive and will pass the variant to all offspring.

What does the result mean?

• Clear (T/T): the tested variant was not detected.
• Positive, one copy (T/C): the dog carries one copy of the causal variant and can develop or pass on MOD.
• Positive, two copies (C/C): the dog carries two copies of the variant and will pass it to all offspring.

Practical value of this test

• The test helps breeders identify MOD in lines early and objectively.
• The result shows which dogs can transmit the dominant variant.
• Breeding combinations can be planned to strongly reduce the risk of puppies with MOD.
• In dogs with eye abnormalities, the DNA result provides targeted context for hereditary cause and line management.
• For young dogs or dogs not yet clinically assessed, the test gives clarity before breeding use.

Because MOD can affect multiple eye structures and cause vision loss, genetic selection is highly practical in this breed. The test makes it possible to manage the variant actively in breeding lines before eye abnormalities become visible.