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The Facts About Dwarfism in Cats

There are several types of dwarfism in cats; here are problems and challenges dwarf cats face.

JaneA Kelley  |  Nov 9th 2016

Dwarfism is pretty rare in cats, but there are a couple of dwarf cats who have become celebrities. Lil BUB and Grumpy Cat have showered the world in their cuteness (Lil BUB) and snarky memes (Grumpy Cat). How did they get that way? Here are the basics on feline dwarfism.

Lil BUB is a dwarf cat.

Lil BUB! Image from Lil BUB’s Facebook page

First, there are three types of dwarfism that affect cats: Osteochondrodysplasia, pituitary dwarfism, and selective dwarfism.

Osteochondrodysplasia (say that three times fast!) is a genetic mutation that produces abnormal bone and cartilage development, leaving a cat with a full-size body but short legs. Other signs of osteochondrodysplasia include a head slightly larger than normal but with a very small jaw, thick-looking joints, and possibly a curved spine and bow-legged posture. Only one parent needs to pass on the gene that produces osteochondrodysplasia, and that parent may not exhibit signs of dwarfism.

Health problems that may arise in cat with osteochondrodysplasia include heart or lung problems, neurological problems, mobility issues, and severely limiting physical defects. Any cat with this syndrome needs to be closely monitored by a veterinarian for her entire life. Lil BUB also suffers from a condition called osteopetrosis, where the bones become very thick and brittle.

A black Munchkin cat

Black Munchkin cat. Munchkins are believed to have a condition called pseudoachondroplasia. Photo CC-BY-NC Veronica Belmont

Pituitary dwarfism, also known as hyposomatrophism, is caused by a shortage of the growth hormones by the pituitary gland. This can be caused by an underdeveloped pituitary gland, cysts on the pituitary, or tumors or infectious diseases that directly affect the gland.

Cats who have pituitary dwarfism don’t grow or develop at the same pace as other cats. Unlike cats with osteochondrodysplasia, in most cases kittens with pituitary dwarfism have heads and bodies that are proportionate. They’ll keep their soft kitten fur, and their teeth may develop slowly as well.

It’s important to figure out whether a tiny kitten with these symptoms has dwarfism or congenital hypothyroidism. Your vet can do that by administering a blood test to measure the level of insulin-like growth factor, or IGF-1. The IGF-1 level in a cat with pituitary dwarfism will be lower than normal.

Because so many organs are affected by pituitary dwarfism, cats with the disease rarely live a full life span. They may have other hormonal abnormalities as well as problems with multiple organs.

Selective dwarfism is just what it sounds like: Breeders encourage the genetic mutation to create short-legged cats like the Munchkin and the Minskin. According to breed research by Sarah Hartwell, Munchkins probably suffer from a genetic defect called pseudoachondroplasia; they have short legs but normally proportioned heads, unlike Grumpy Cat and Lil BUB.

The breeding of cats with genetic abnormalities is hotly debated. Outside the U.S., dwarf breeds are not widely accepted. In fact, some registries prohibit those breeds as an unacceptable mutation of “genetic disease.”

Munchkins are particularly prone to arthritis because of the stress of the body’s weight on their shortened limbs.

Grumpy Cat is a dwarf kitty

Grumpy Cat. Photo from the Official Grumpy Cat Facebook page

All dwarf cats are prone to obesity, and because of their abnormal bone structure, it’s crucial to keep your dwarf cat at an appropriate weight. Keep in mind, too, that dwarfism can be very painful for your cat, so make sure you work with your vet to devise an adequate pain control regimen so she’ll have a good quality of life.

Remember that although Lil BUB, Grumpy Cat, and short-legged breeds like the Munchkin are cute, they can suffer from a broad range of health issues that can cause great expense and heartbreak for cat guardians.

I’d encourage you to enjoy all the dwarf cat photos and videos you can stand, but please think twice before buying a cat who has been bred to encourage a potentially painful genetic defect.


Munchkin kittens. Photo by Shutterstock

Do you have a dwarf cat? Have you known any dwarf cats? Please share your thoughts on dwarfism and your stories and photos of dwarf cats in the comments.