Coat colour dilution factor / D locus (MLPH-related) - Cat

Dilution factor in cats

This genetic test detects the MLPH variant c.83delT, the classic dilution factor at the D locus. The trait is also known as dilution, dilute, blue, lilac or fawn, depending on the cat’s base colour.

What does dilution do?

MLPH affects transport of pigment granules in the hair follicle. When a cat has two copies of the dilution variant, black becomes blue, chocolate becomes lilac and cinnamon becomes fawn. Red and cream shades can also become lighter, while other coat-colour genes continue to shape the final coat colour.

Why this test is useful

• The test shows whether the cat is clear, a carrier or genetically dilute for the MLPH variant.
• Breeders can plan or avoid dilute colours deliberately.
• The result helps interpret colour expectations together with B-, C- and E-locus results.

The dilution factor is inherited as autosomal recessive: one copy means carrier status, while two copies cause the dilute coat colour.