The title describes disorders that produce degenerative changes in the central nervous system. They are determined by inherited genes. In each of the conditions listed a specific enzyme needed for nerve cell metabolism was missing. These conditions affect purebred cats and breeder should do their best to eliminate carriers from their breeding programme.
Metabolic nervous system diseases are normally inherited as autosomal recessive traits. This is the inheritance of non-sex-linked recessive genes. In order for a recessive gene to be inherited by offspring, both parents must carry it. Littermates who don’t show signs of the disease may carry the trait. Carriers should be identified by DNA or special enzyme tests in order for the cat to be removed from the bloodline. Signs normally appear at or shortly after weaning.
The symptoms include muscle tremors and loss of coordination. The kitten may walk with difficulty and the gait may be wobbly and unstable. Late signs of the disease include seizures, blindness, paralysis of the back limbs and weakness.
Many of the problems involved enzyme deficiencies or defects in metabolism which leads to a buildup of metabolic waste products. As at 2008, there was no treatment for most of these conditions which means reliance has to be placed on removing the cats carrying these inherited traits from the bloodline as mentioned.
Here’s a list:
- GM1 – gangliosidosis – Signs are corneal clouding and ataxia (poor coordination). Seen in Oriental breeds such as the Oriental SH.
- GM2 – familial amaurotic idiocy – signs include ‘behavioural deficits’, vision problems, ataxia and head tremors. Seen in Korats and domestic shorthairs (presumed the general domestic cat population including non-purebreds).
- Niemann-Pick – sphingomyelinosis – signs include enlarged abdomen due to enlarged spleen and liver. Seen in Siamese cats. ‘Deficits’ vary according to the disease’s subtype.
- Mannosidosis – signs include bone abnormalities, visual deficits, behavioural abnormalities. Seen in Persian kittens and random bred shorthairs and longhairs. – Persian inherited diseases.
- Glycogenolysis type IV – signs include seizures, muscle atrophy, abnormal walk and fever. Seen in Norwegian Forest cats.
- Mucopolysaccharidosis type 1 – signs include bone dysplasias (abnormal development), clouding of the cornea of the eye, lameness, flattened face. Seen in domestic shorthaired cats.
- Mucopolysaccharidosis type VI – seizures (rare), rear limb paresis (muscle weakness), abnormal bones, flattened face. Seen in Siamese cats.
- Ceroid lipofuscinosis – signs include: seizures, ataxia, visual deficits. Seen in Siamese cats.
- Hereditary hyperchylomicronemia – mild signs include ataxia at about 8 months of age. Low fat diet might help according to Cat Owner’s Home Veterinary Handbook (3rd ed.) at page 338, which is the source of this information.
- Spongiform degeneration – signs include: behavioural problems, tremors, abnormally exaggerated movements (hypermetria), ataxia. Seen in Burmese and Egyptian Maus.
SOME MORE ON GENETICALLY INHERITED DISEASES:
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