Cornell researchers document first case of Marfan syndrome in cats

Researchers at Cornell University have documented the first molecular characterization of Marfan syndrome in domestic cats in a paper in Scientific Reports.

As kittens, feline siblings Gary and Shaggy had noticeably longer limbs, and later examinations revealed problems with the structures of their eyes and enlargement of the aorta. That pointed veterinarians toward Marfan syndrome, a rare inherited disorder, seen mostly in humans, that weakens the body's connective tissues. It affects about 1 in 4,000 people, but this was the first known documented case in cats.

The findings provide a foundation for improved veterinary diagnostics. It can help veterinarians recognize similar cases in the future and may help develop genetic tests."

Dr. Jacquelyn Evans, senior author, assistant professor, College of Veterinary Medicine and Baker Institute for Animal Health

A multidisciplinary team combined detailed clinical evaluations with genetic sequencing to identify the gene responsible for the feline siblings' condition: FBN1, which codes for a protein called fibrillin-1, a building block of the body's connective tissues found throughout the body, including in blood vessels, bones, ligaments, skin and eyes.

Researchers found that both brothers carried two altered copies of the FBN1 gene, meaning they inherited a changed copy from each parent. In humans, just one altered copy of the FBN1 gene can cause Marfan syndrome. Inheriting two altered copies is extremely rare and can interfere with the body's ability to produce normal fibrillin-1.

In the case of Gary and Shaggy, however, further investigation showed that the cats' variant did not completely shut down the gene. Instead, it partially disrupted the way the gene's instructions are processed, allowing some normal function to remain - explaining how the cats survived into adulthood despite carrying two copies of a variant that otherwise might have caused more severe disease.