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What is diprosopus in cats?

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Diprosopus in cats: all there is to know

By Dr Holly Graham BVMedSci BVMBVS MRCVS Veterinarian

Updated on the

Diprosopus in cats is an extremely rare condition which causes parts of a cat's face to duplicate. It can affect specific features like the eyes or nose.

In a tiny number of cases, the entire face duplicates, meaning the cat is born with two faces. Most of us will never see one in our lifetime, but the condition is curious!

Let's take a closer look at two-faced cats, including a couple of inspiring kitties who overcame the odds!

Diprosopus cats 

Diprosopus is also known as craniofacial duplication, but you're more likely to hear the term Janus cats. The name comes from ancient Roman mythology. Janus is the Roman god of beginnings and endings. As such, he is usually depicted with two faces; one is looking to the future, the other peering into the past.

Unfortunately most animals born with the condition do not survive because of multiple brain and internal organ abnormalities.

Two-faced cats: How do they get that way?

This rare condition is caused by the abnormal development of the SHH protein. The protein is part of a group of genes that play a crucial role in organising the brain of vertebrate animals, as well as the number of facial features and their symmetry. It also controls the widening of the face during embryonic development. As the face starts to grow, it naturally duplicates features like eyes and ears. But if it continues to widen, it will make additional copies of these features, and sometimes a second face!

The gene is interestingly shaped like a hedgehog, so scientists began naming each new gene in the group after types of hedgehogs. The SHH protein that leads to diprosopus is more commonly referred to as the Sonic the Hedgehog protein or the Sonic the Hedgehog gene.

Diprosopus is not related to conjoined twinning, in which a single embryo only partially separates in the womb.

How long do Diprosopus cats live for? 

Unfortunately, because of the severe complications associated with the condition, infants with diprosopus have a life expectancy of just four days. But veterinary medicine is always advancing, and miracles do happen! In 2012, Frank and Louie entered into the Guinness Book of Record as the oldest living two-faced cat at age 12, This special cat had a single trachea and oesophagus, which helped to reduce the problems caused by the genetic defect. Although he needed a little more care and attention than most kitties, his owners said Frank and Louie lived a happy life full of cat treats, playtime, and snuggles.

There are several other case reports of two-faced cats defying the odds, including the inspiring story of Duo the Kitten. The kitten found a forever home with Dr Ralph Tran after being rejected by her mother. She overcame respiratory infections, as well as other health complications. Duo is living a happy life with her human and animal friends, and is a social media celebrity!

Does diprosopus affect humans? 

Diprosopus does occur in humans, although only a handful of infants born with the condition survive past the first few weeks. One notable exception was Lali Singh. She was born in a small village outside Delhi, India. Lali beat all the doctor's expectations and lived for two months before dying of a cardiac arrest. She was buried in her village, and the locals later built a temple to honour her memory.

Janus cats are as rare as they are special. And although these unique kitties certainly have their struggles, the ones that make it end up leaving a big impression on the world. In fact, record-breaking cats like Frank and Louie will live on in human memory forever, while fighters like Duo the Cat continue to astound us!


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