Free tools Windows power users keep installed
One-click scans. No signup required.
Two domestic-cat littermates, Gary and Shaggy, are the first cats described in a published study with both the clinical signs and molecular findings of Marfan syndrome. Researchers linked their condition to a specific variant in FBN1, a gene involved in making fibrillin-1. Their case shows how a change in RNA processing may disrupt the gene while still leaving some normal transcript—a finding specific to these cats, not evidence that the syndrome is common in cats.
What Marfan syndrome looked like in Gary and Shaggy
The cats had signs affecting three body systems:
- Skeletal: unusually long limbs.
- Ocular: lens luxation in both eyes, meaning the lenses had shifted from their normal positions.
- Cardiovascular: dilation of the aortic root, the part of the aorta nearest the heart.
Researchers also examined tissue from the ascending aorta of an affected cat. They observed disrupted, fractured elastic-fiber tendrils, consistent with impaired fibrillin-1 function. The primary study describes this first phenotypic and molecular characterization of feline Marfan syndrome in Scientific Reports, published 19 September 2026; the publisher labels the accessible article an early version that may receive further edits.
What gene variant did the researchers identify?
Whole-genome sequencing found a homozygous variant in FBN1, meaning the cats had the variant on both copies of the gene. Its reported designation is XM_023255387.2:c.2678-3C>A. It lies three base pairs upstream of exon 22, in a region that can affect how the gene’s RNA is spliced.
The study reports that the variant was absent from a comparison cohort of more than 1,000 cats. That finding helps distinguish the variant in the reported cases; it is not a population estimate of Marfan syndrome or proof that the variant never occurs in any other cat.
#1 Best Overall
How the variant affected FBN1 transcripts
To examine the effect on RNA, the researchers used Oxford Nanopore sequencing on cDNA from an affected cat. They found that exon 22 was skipped in 73% of the transcripts assessed. Exon 22 encodes part of the second hybrid domain, which the study describes as important for protein folding and stability.
The splice change did not eliminate normal transcript altogether. A low level of correctly processed transcript remained, so the authors characterized the variant as hypomorphic: it reduces gene function rather than causing complete loss of function. They describe the cats as functionally heterozygous despite their homozygous DNA result, because some normal transcript was still produced.
The authors propose that this residual normal transcript may help explain how cats with two altered copies survived. It does not establish how other FBN1 variants would behave, or whether they would leave a similar amount of normal transcript.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Can cats get Marfan syndrome, and what does this report establish?
These cases show that cats can have a Marfan-like condition associated with an FBN1 variant. The study is a report about two littermates, not a prevalence survey, screening trial, or treatment study. It cannot show how often the condition occurs in cats or support a particular treatment recommendation.
The findings add a spontaneous animal case to comparative understanding of FBN1-related disease. A Cornell-attributed summary published 1 October 2026 quotes senior author Dr. Jacquelyn M. Evans as saying the findings may help veterinarians recognize similar cases and may help develop genetic tests. That is a possible future application, not confirmation of a validated or commercially available feline test or a clinical screening protocol. The summary is available from Cornell.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
