Cornell scientists confirm Marfan syndrome in two domestic cats for the first time

Researchers at Cornell University's College of Veterinary Medicine have reported the first genetically confirmed cases of Marfan syndrome in domestic cats, describing two brothers with unusually elongated limbs whose condition matches the connective-tissue disorder long documented in humans.

Marfan syndrome in people is caused by variants in the FBN1 gene, which encodes fibrillin-1, a protein essential to connective tissue integrity. The Cornell team found that the two cats each carried two altered copies of the gene associated with the condition — a homozygous state. The cats displayed skeletal features consistent with Marfan syndrome, including the striking limb elongation that drew researchers' attention. The finding was published via ScienceDaily reporting on the Cornell study.

Notably, both cats survived into adulthood, which the researchers attribute to the specific nature of their mutation: it appears to preserve some residual protein function, unlike variants that eliminate fibrillin-1 activity entirely. This partial function may have been sufficient to avert the most severe cardiovascular complications — aortic dissection in particular — that often prove fatal in Marfan syndrome.

The case is of interest to comparative geneticists and veterinary researchers because naturally occurring large-animal models of human connective-tissue disorders are rare. For researchers studying fibrillin-1 biology and for educators illustrating autosomal recessive inheritance and variable expressivity, the cats represent an instructive example. The full study details, including the journal of publication, were not available from feed reporting alone.