Cornell veterinary researchers have identified what they say is the first documented molecular case of Marfan syndrome in domestic cats, tracing the inherited connective-tissue disorder in two brothers to changes in the FBN1 gene.
The Cornell Chronicle reported that the findings appeared in the Sept. 19 issue of Scientific Reports. Senior author Jacquelyn Evans, an assistant professor at Cornell's College of Veterinary Medicine and Baker Institute for Animal Health, said the work could help veterinarians recognize similar cases and eventually develop genetic tests.
The cats, Gary and Shaggy, had unusually long limbs as kittens. Later examinations found structural problems in their eyes and enlargement of the aorta, the large blood vessel that carries blood away from the heart. Those findings led veterinarians to investigate Marfan syndrome, an inherited condition that weakens connective tissue.
Genetic testing explains the diagnosis
Cornell specialists worked with collaborators at Ghent University in Belgium, the University of Pennsylvania and the Schwarzman Animal Medical Center in New York City. The team combined clinical examinations with genetic sequencing to identify altered copies of FBN1 in both cats.
FBN1 provides instructions for making fibrillin-1, a protein important to connective tissues in blood vessels, bones, ligaments, skin and eyes. Each brother carried two altered copies, one inherited from each parent, according to Cornell.
In people, one altered FBN1 copy can cause Marfan syndrome. Inheriting two altered copies is extremely rare and can interfere with the body's ability to make normal fibrillin-1. Cornell said the variant found in Gary and Shaggy did not completely shut down the gene.
Instead, it partly disrupted how the gene's instructions were processed, leaving some normal function. The researchers said that finding helps explain how the brothers survived into adulthood despite carrying two altered copies that might otherwise have caused more severe disease.
What the finding could mean for veterinarians
Marfan syndrome has been recognized primarily in people, where Cornell says it affects about one in 4,000. The researchers described the brothers as the first known documented feline cases characterized at the molecular level, not evidence that the condition is common in cats.
Evans said cooperation between the cats' owners and veterinary and genetics specialists made the investigation possible. She said identifying the variant gives veterinarians a starting point for recognizing comparable cases in the future, while any genetic test would still need to be developed.
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