Flat Chested Kitten Syndrome (FCKS)

Flat Chested Kitten Syndrome (FCKS)

Health & Safety

Flat Chested Kitten Syndrome (FCKS) affects certain breeds more than others with the condition being characterised by a deformed chest and flat rib cage. However, the problem affects a kitten's spine and sternum too. When a kitten is flat chested they often suffer from another condition known as pectus excavatum (PE) which is also referred to as funnel chest"" which is a congenital malformation closely associated with Flat Chested Kitten Syndrome.

Breeds Most at Risk

As previously mentioned, certain breeds are more predisposed to suffering from the condition than others, and this includes the following breeds:

  • Burmese
  • Bengal
  • Oriental

Symptoms to Watch Out For

Kittens with the condition are often happy, alert and active unless the malformation is very severe and when they survive, as they mature their symptoms often become less obvious than when they were first born. With this said, signs there is a problem often include the following:

  • Trouble putting on weight
  • Weight loss
  • Vomiting
  • A reluctance to play or exercise
  • Depression/lethargy
  • Difficulty suckling from their mother
  • Laboured breathing/panting
  • Coughing
  • Tachypnea
  • Heart murmur
  • Recurrent lower respiratory infections
  • Cyanosis

It is worth noting that when a kitten has the condition, they often have splayed legs which is referred to them being ""swimmers"". If a kitten has also developed pectus excavatum, they may also have a pericardio-diaphragmatic hernia.

The Causes

Breeders are aware of the condition, however not much research has been carried out into why some breeds are more predisposed to suffering from Flat Chested Syndrome than others. With this said, studies have suggested there may be a genetic link to the condition although environmental factors may also play a key role in why some kittens are born with the disorder and others are not.

Diagnosing the Condition

A vet would need to have a kitten’s full medical history and ideally know their ancestry too. They would carry out a full physical examination of the kitten to determine the exact extent of the malformation and to establish whether they have developed PE or not. A vet would also rule out any other reasons why a kitten may be showing any symptoms of there being something wrong with them and this includes ruling out whether they are suffering from the following conditions:

  • Fading Kitten Syndrome
  • Respiratory tract infections
  • Heart defects

Treatment Options

Some cats with the disorder recover from their condition spontaneously without any veterinary intervention. However, when the condition is very severe treatment can prove more challenging. Making sure a kitten eats enough is essential so they maintain muscle strength and it helps stabilise their condition. Surgery is seldom an option, unless a vet thinks there is a good chance of being able to correct a pectus excavatum (PE) problem.


The prognosis for kittens with a flat chest defect depends on the severity of their condition which can be mild to extremely life-threatening. In some instances, a kitten may succumb to the malformation when they are anything from ten to twenty-one days old whereas in other kittens, the condition is such that dyspnea sets it which means it is kinder to put them to sleep because they have such trouble breathing. However, as previously mentioned, some kittens develop normally and as they mature, the deformity becomes less obvious and as such they can lead full and normal lives providing their lungs and hearts have not been impacted by the malformation.




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