In cats most cases of hypokalaemic myopathy (muscle weakness due to low levels of blood potassium) are associated with chronic renal (kidney) failure. However, it can also be seen in young Burmese kittens from 2-6 months of age, where a transient increase in the amount of potassium entering the cells can result in muscle weakness. The most obvious clinical signs are generalised muscle weakness, ventroflexion (extreme weakness) of the neck, a stiff stilted gait, reluctance to walk, and muscle pain, with head tremors, peculiar knuckling of the carpus (wrists), a tendency to sink on their hocks, and to sit with their stifles abducted (knees out). Clinical signs may be induced by exercise, stress or cold weather. Severely affected cats may collapse and die of respiratory paralysis.

Testing for hypokalaemia
Diagnosis is made by checking the serum potassium concentration (which will be low) and serum creatine kinase (an enzyme which indicates muscle damage) concentration (which will be increased). Langford Veterinary Services (LVS), a wholly owned subsidiary of the University of Bristol, now offers a gene test to help identify Burmese cats that carry the mutation responsible for Burmese hypokalaemia.

For further information, contact LVS on:
telephone: 0117 928 9412
email: genetic.tests@langfordvets.co.uk
or visit: http://www.langfordvets.co.uk/lab_pcr_hypokalaemia.htm

Treatment is by supplementation with oral potassium.

Register
FAB has set up a register for breeders with cats that have been tested for hypokalaemia.  Because it is an autosomal recessive disease, carrier cats do not show signs of the disease, but kittens which result from the mating of two carriers are likely to have the following risk of being affected - 25% normal, 50% carrier and 25% affected.  Click here to access the register.

Which other breeds may be affected?

Because the Burmese breed has been used in developing other breeds, the following may also be at risk but likely to be considerably lower.  Asian, Australia Mist, Bombay, Burmilla, Cornish Rex, Devon Rex, Singapura, Sphynx, Tiffanie and Tonkinese.

Terms of the register

• FAB will only accept test results if the cat has been microchipped.
• FAB would need to have a copy of the signed certificate from the Langford Laboratory, showing that the microchip number had been verified by a vet and counter-signed by the vet in question.
• FAB would need to make a charge of £5 per cat for creating and maintaining the register.
• FAB will record results as either 'normal', 'carrier', or 'affected' as per the Langford Vets results in order to identify and distinguish carriers from non-carriers to allow appropriate breeding selections.

If you would like to have your cat entered on the register please send your certificate(s) as outlined in the terms above, togther with a cheque made payable to 'Feline Advisory Bureau' to:

Feline Advisory Bureau
Taelesbury
High Street
Tisbury
Wiltshire
SP3 6LD