Test Detail
Alpha-mannosidosis (AMD)
Metabólico · Cat
Alpha-mannosidosis is a hereditary lysosomal storage disease of the Persian cat, caused by a deficiency of the enzyme acid alpha-mannosidase (MAN2B1 gene). The defect prevents the breakdown of oligosaccharides, which accumulate in neurons and other cells, producing progressive neurodegeneration. Affected kittens develop ataxia, tremors and general deterioration in the first months of life, progressing to death or euthanasia. There is no treatment and control is based on avoiding matings between carriers.
Incidence
Very rare disease. Classically described in the Persian cat and in short-haired domestics of certain populations. There are no current carrier frequency figures (limited data); current cases are sporadic.
Breeder management
- Test Persian breeding animals from lines with a history of early ataxic kittens\n- Never mate carrier with carrier: 25% risk of affected kittens\n- A carrier can be mated to a clear animal, keeping only clear offspring for breeding if you aim to eliminate the allele\n- With kittens showing progressive ataxia and tremors, first rule out infectious and metabolic causes and request a workup for storage diseases\n- Record the results together with the pedigree at the breed club
Specialist notes
The differential diagnosis includes other feline storage diseases (type IV glycogenosis, mucopolysaccharidosis, lipofuscinosis), cerebellar abiotrophies and infectious or toxic encephalopathies. Laboratory workup relies on urinary excretion of oligosaccharides, vacuoles in lymphocytes on the blood smear and deficient alpha-mannosidase activity in leukocytes; DNA testing confirms the status. There is no effective treatment (bone marrow transplantation has been experimental); management is palliative and genetic counselling is mandatory after a case.
References
1. Burditt LJ et al. 1980. Biochemical studies on a case of feline mannosidosis. Biochem J. PMID: 7213340
2. Abraham D et al. 1983. The catabolism of mammalian glycoproteins. Comparison of the storage products in bovine, feline and human mannosidosis. Biochem J. PMID: 6661184
3. Raghavan S et al. 1988. Characterization of alpha-mannosidase in feline mannosidosis. J Inherit Metab Dis. PMID: 3128686
4. Berg T et al. 1997. Purification of feline lysosomal alpha-mannosidase, determination of its cDNA sequence and identification of a mutation causing alpha-mannosidosis in Persian cats. Biochem J. PMID: 9396732
5. Vite CH et al. 2001. Histopathology, electrodiagnostic testing, and magnetic resonance imaging show significant peripheral and central nervous system myelin abnormalities in the cat model of alpha-mannosidosis. J Neuropathol Exp Neurol. PMID: 11487056
6. Sun H et al. 1999. Retrovirus vector-mediated correction and cross-correction of lysosomal alpha-mannosidase deficiency in human and feline fibroblasts. Hum Gene Ther. PMID: 10365662
OMIA000625-9685.
2. Abraham D et al. 1983. The catabolism of mammalian glycoproteins. Comparison of the storage products in bovine, feline and human mannosidosis. Biochem J. PMID: 6661184
3. Raghavan S et al. 1988. Characterization of alpha-mannosidase in feline mannosidosis. J Inherit Metab Dis. PMID: 3128686
4. Berg T et al. 1997. Purification of feline lysosomal alpha-mannosidase, determination of its cDNA sequence and identification of a mutation causing alpha-mannosidosis in Persian cats. Biochem J. PMID: 9396732
5. Vite CH et al. 2001. Histopathology, electrodiagnostic testing, and magnetic resonance imaging show significant peripheral and central nervous system myelin abnormalities in the cat model of alpha-mannosidosis. J Neuropathol Exp Neurol. PMID: 11487056
6. Sun H et al. 1999. Retrovirus vector-mediated correction and cross-correction of lysosomal alpha-mannosidase deficiency in human and feline fibroblasts. Hum Gene Ther. PMID: 10365662
OMIA000625-9685.