Hair morphology, Glitter (FGFR2-related)

Gene: FGFR2

Transmission: Autosomal recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease.  Both parents of an affected animal must be carriers of at least one copy of the mutation.  Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Insertion, FGFR2 gene (endogenous retroviral): 585-bp LTR repeat element inserted 287 bp upstream of a FGFR2 enhancer element within intron4-5 of the FGFR2 gene, Chr.D2.

Medical system: Dermal

Breed: Bengal, Egyptian Mau, Toyger

Age of onset of symptoms: At birth

The “Glitter” phenotype seen in the Bengal cat breed affects cat hair structure and density.  It is characterized by a golden or silver sheen to the coat, creating the illusion that the hairs sparkle in the light. It is the result of a more translucent hair shaft that reflects and refracts light differently. The coats of Bengal cats with the glitter trait are also softer and silkier compared to the coats of cats without this trait.

The glitter mutation is associated with the insertion of a retrovirus (LTR, Long Terminal Repeat) of about 585 bp within intron 4-5 of the FGFR2 gene. The FGFR2 gene product is a receptor protein for a growth factor important during embryonic development and for wound healing.  The mutation is a “hypomorph”, reducing but not eliminating FGFR2 gene expression, which results in the glitter hair phenotype without causing any additional developmental effects.  The mutation arose naturally within the Bengal breed of cats, from which it has been transferred to the Egyptian Mau and the Toyger breeds of cat.

Because hair forms in utero, the glitter trait is observable from birth and remains throughout the animal’s life. Glitter is considered an aesthetic trait that has no influence on the cat’s health or behavior.

References:

OMIA link: [1313-9685]

Kaelin CB, McGowan KA, Hutcherson AD, et al. (2024) Ancestry dynamics and trait selection in a designer cat breed. Curr Biol 34:1506-1518.e7.  [pm/38531359]

Lyons LA. (2024) Genetic testing: practical dos and don’ts for cats.  J Feline medicine and surgery 26:1-13.  [pm/39648935]

With contributions by: Anne-Marie Andrei and Mark-Olivier Gingras, Class of 2030, Faculty of Veterinary Medicine, University of Montreal.  (Translation: DWS).