Cornell researchers have reported the first molecularly characterized cases of Marfan syndrome in domestic cats. The patients, brothers named Gary and Shaggy, first drew attention as kittens because of their unusually long limbs. Later examinations found eye abnormalities and an enlarged aorta, and DNA sequencing identified alterations in FBN1, the gene that makes the connective-tissue protein fibrillin-1.
What disease did Cornell find in the cats?
The Cornell University College of Veterinary Medicine and the Baker Institute for Animal Health diagnosed Gary and Shaggy with feline Marfan syndrome. Cornell describes the report as the first known documented domestic-cat cases with a molecular characterization of the disorder.
As an Amazon Associate I earn from qualifying purchases.
Marfan syndrome is an inherited connective-tissue disease. Connective tissue provides structural support throughout the body, including in blood vessels, bones, ligaments, skin and the eyes. In people, the condition is associated with features such as unusually long limbs, eye changes and weakness or enlargement of the aorta. Cornell says human Marfan syndrome affects about one in 4,000 people.
How veterinarians recognized the condition
The cats’ long limbs provided the first clue
Gary and Shaggy had strikingly long legs as kittens. Limb proportions alone cannot establish Marfan syndrome, but they prompted closer veterinary assessment rather than being treated as an ordinary body-type variation.
#1 Best Overall
- EASY TO USE, IMPACTFUL RESULTS: Collect a sample, package it up, and send it securely back. Just register, swab, return with the included pre-paid mailer, and receive a detailed online report in 4-6 weeks!
- MOST COMPREHENSIVE BREED & TRAIT: Our test distinguishes over 20+ distinct breeds and 50+ trait markers with the most scientifically advanced cat DNA test kit for breed similarity.
- SCREEN FOR 40+ GENETIC DISEASES: Get peace of mind by screening for 64 health markers associated with 43 diseases for which your cat may be genetically predisposed. Early detection helps you and your veterinarian get ahead of diseases before they become life-threatening.
- ONLY TEST WITH ACTIVE ORAL HEALTH REPORT: 70-90% of cats have active oral health issues. Be proactive in care for periodontal disease, bad breath, and tooth resorption to safeguard against diabetes, chronic kidney and heart disease, and other conditions
- VET-TESTED, PET-PARENT APPROVED: Basepaws has been trusted by tens of thousands of pet parents, veterinarians and even Sharktank to provide the most actionable insights to help create care plans for your furry friend
Eye and aortic findings supported the diagnosis
Follow-up examinations identified abnormalities in the cats’ eye structures and enlargement of the aorta, the major artery leaving the heart. The combination of skeletal, ocular and cardiovascular findings pointed toward a connective-tissue disorder consistent with Marfan syndrome.
Sequencing supplied molecular confirmation
Researchers then sequenced the cats’ DNA and found changes in FBN1. The gene encodes fibrillin-1, a structural component that helps connective tissues maintain their organization and strength. The genetic result matched the clinical pattern, providing the molecular evidence needed to characterize the disease in these cats.
Rank #2
- The most comprehensive cat DNA test. Wisdom Panel identifies 70+ breeds and populations. Know your cat like never before. Our detection system offers the most precise breed report available leveraging the world’s largest cat breed reference panel.
- 45 Genetic health tests deliver comprehensive health insights. Receive a free Wisdom Panel veterinary genetics specialist consult if you get an ‘at risk’ health result so you and your vet can create a plan that helps them stay healthy, happy and well.
- Identify physical features with 25+ trait tests. Wondering why your cat looks the way they do? Learn how their one of a kind appearance came to be—and how to keep them looking (and feeling) their best.
- Know their blood type. Just like with humans, blood type can be important info in an emergency. Identify your cat’s blood type, so you’re ready in case they ever need a blood transfusion.
- 5M+ Pets tested in 50+ countries. Developed by veterinarians and geneticists, loved by pet parents. Every test furthers research focused on improving the health and wellbeing of all pets.
What is the FBN1 mutation in Gary and Shaggy?
Both brothers carried two altered copies of FBN1: one inherited from each parent. The reported change lies in a splice region, where cells process the gene’s instructions into messenger RNA. It is described as a hypomorphic variant, meaning that it reduces gene function without eliminating it completely.
That partial activity matters. A variant that entirely abolished fibrillin-1 production could be expected to cause a much more severe outcome. In Gary and Shaggy, the splice-region change left enough normal function for the brothers to survive into adulthood, while still disrupting connective-tissue biology sufficiently to produce the observed signs.
Rank #3
- THE ALL-ROUND HEALTH TEST FOR BREEDERS AND CAT OWNERS: The CatCheck test screens for more than 75 inherited diseases, blood group, traits, coat colours and coat types. Results are issued by email within 4-6 weeks of receipt of samples at the laboratory. This test does not provide any information about your cat’s breed.
- THE COMPREHENSIVE GENETIC HEALTH REPORT for your feline provides one of three possible outcomes – Clear, Carrier or At Risk - and will help you identify risks of genetically inherited diseases. Please check the images for a full list of the inherited diseases, traits, coat colours and types covered by this test.
- SIMPLE & EASY SAMPLE COLLECTION: Samples can be collected simply & painlessly using the supplied cheek swabs. Results are issued by email within 4-6 weeks of receipt of samples at the laboratory.
- COMPLETE TESTING KIT: The DNA Sample Collection Kit contains 2 x sterile mouth swabs (both for 1 cat), step-by-step sample collection instructions, registration form & return envelope.
- ABOUT US: AffinityDNA is an industry-leading DNA Testing company with more than 15 years’ experience in the DNA business & established partnerships with some of the most highly accredited DNA testing laboratories in the world.
The finding also distinguishes the feline cases from the usual human inheritance pattern. In humans, one altered copy of FBN1 can cause Marfan syndrome. The Cornell cats instead had two altered copies, consistent with the particular variant and family history reported in the paper. This does not mean every cat with an FBN1 change would inherit or express the disorder in the same way.
Can cats get Marfan syndrome?
Yes. The Cornell report establishes that domestic cats can develop a Marfan-syndrome phenotype and that the condition can be tied to an FBN1 variant. However, these are newly characterized cases, not evidence that the disorder is common in cats. The report does not provide a population prevalence, a catalog of all feline variants or a general screening rule for every long-legged cat.
Rank #4
- SAFE, EASY & AFFORDABLE CAT AGE TEST: The EpiPaws Cat Age Test is an at-home DNA-based age test for cats. Use science to discover your cat’s age with a simple mouth swab test that measures DNA methylation at specific areas of the genome.
- SWAB, MAIL, GET RESULTS: Register your kit, create your cat’s pet profile, swab your cat’s cheek, print a return label, and mail the sample back to the lab. Results are available online in approximately 4–6 weeks from sample receipt.
- INCLUDES ESTIMATED BIRTHDAY & LIFE STAGE: Results include your cat’s age estimate, suggested birthday, life stage, and life stage-specific health insights. Reports can be viewed online and downloaded or printed.
- GREAT FOR RESCUE & SHELTER CATS: Perfect for adopted cats, rescue cats, shelter cats, or any cat without a known birthday. A more accurate age estimate can help you better understand your cat’s needs and provide age-appropriate care. Not suitable for kittens.
- BE MORE PROACTIVE WITH YOUR CAT’S CARE: Knowing your cat’s age and life stage can help guide nutrition, exercise, behavior expectations, preventive care, and overall wellness. Health insights are specific to your cat’s life stage. Health markers are not measured in this test.
Long limbs by themselves are not diagnostic. A veterinarian would need to evaluate the animal’s history and perform appropriate examinations, potentially including cardiac imaging, eye assessment and genetic analysis. An enlarged aorta can be medically serious, so a cat with unusual body proportions plus eye or cardiovascular findings should be assessed by a veterinarian rather than judged from appearance.
What the discovery could change in veterinary medicine
Improved recognition of similar cases
The report gives clinicians a documented combination of signs to consider: disproportionate limb length, ocular abnormalities and aortic enlargement. Recognizing that pattern may help veterinarians distinguish a possible connective-tissue disorder from normal variation or unrelated diseases.
Best Value
- 1100+ ITEM PET INTOLERANCE AT-HOME FUR SAMPLE INSIGHT KIT - Explore personalized pet intolerance insights to over 1100 foods, ingredients, nutritional items, environmental items, and pet care products. Designed to help pet owners better understand and organize ingredient-related information.
- FOODS AND INGREDIENTS, NUTRITIONAL ITEMS, ENVIRONMENTAL ITEMS & PET CARE PRODUCTS - Comprehensive reporting includes foods, ingredients, environmental factors, nutritional components, additives, and common pet care items, providing a broad overview in one easy-to-use system.
- RESULTS READY WITHIN 2 BUSINESS DAYS OF RECEIVING YOUR SAMPLE - Our test kit delivers accurate, easy-to-read, color-coded results, helping you understand how your pet’s diet and lifestyle may be affecting their quality of life by identifying potential intolerances and sensitivities. Move from uncertainty to informed decisions quickly once you receive your pet's results.
- VETERINARIAN-APPROVED WITHOUT A VISIT - Our painless, non-invasive, and affordable at-home testing solutions are backed by veterinary professionals. With no vet visits, waiting rooms, needles, or additional costs, you can easily perform our intolerance test on your dog or cat from the comfort of your home.
- ALL-IN-ONE DIGITAL RESULTS DASHBOARD - Access your personalized digital report and available Ingredient Checker in one convenient online dashboard. With the add-on option of our Ingredient Checker, you can search for ingredients, compare pet food formulas, and make more informed decisions every day with confidence.
A possible path to genetic testing
Senior author Dr. Jacquelyn Evans, an assistant professor in Cornell’s Department of Biomedical and Translational Sciences and at the Baker Institute for Animal Health, said the findings “provide a foundation for improved veterinary diagnostics” and may help develop genetic tests. That is a research direction, not an announcement of an available commercial test. The reports do not establish a validated test for routine sale, a recommended breeding panel or a treatment specific to this feline variant.
A comparative model for human disease
Because fibrillin-1 is important across species, the cats may also help scientists study how partial loss of FBN1 function affects connective tissue. The feline variant’s residual activity offers a way to examine a form of disease that is neither normal gene function nor complete loss of the protein. Any medical insight for people remains prospective; the publication is a feline case report, not a human clinical trial.
How the feline and human cases differ
| Feature | Gary and Shaggy | Human Marfan syndrome |
|---|---|---|
| Gene | FBN1, which encodes fibrillin-1 | FBN1, which encodes fibrillin-1 |
| Copies reported | Two altered copies, one from each parent | One altered copy can cause the disorder |
| Molecular effect | Hypomorphic splice-region variant with residual function | Human variants can have different molecular effects; the Cornell paper does not redefine the human spectrum |
| Clinical clues in this report | Long limbs, eye abnormalities and enlarged aorta | Connective-tissue features can include skeletal, ocular and aortic involvement |
| Diagnostic maturity | Newly characterized feline cases | Established clinical recognition and genetic diagnosis |
Publication and collaborators
The findings appear in the peer-reviewed paper “A homozygous hypomorphic FBN1 splice region variant in domestic cats with Marfan syndrome,” published in Scientific Reports in 2026 (DOI: 10.1038/s41598-026-70702-3). The collaboration included Cornell University, Ghent University in Belgium, the University of Pennsylvania and the Schwarzman Animal Medical Center in New York City.
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Evans also said the case shows how pet owners can work with veterinary and genetic specialists to investigate unusual conditions. For now, the practical value is recognition and documentation: owners should not assume that a tall, long-legged cat has Marfan syndrome, and veterinarians should base any diagnosis on clinical examination supported by imaging and, where appropriate, genetic testing.
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.
