Mucopolysaccharidosis Type IIIA (SGSH gene, Dachshund)

Mucopolysaccharidosis IIIA is a lysosomal storage pathology caused by mutations in the SGSH gene encoding the sulfamidase enzyme involved in the degradation of heparan sulfate. Because it cannot be degraded properly, heparan sulfate accumulates in the tissues and is particularly harmful to the nervous system.


This type of mucopolysaccharidosis causes spinocerebellar ataxia which usually appears before 4 years of age and progresses slowly. Affected dogs have trouble walking and often trip and fall. Tremors are also observed when the dog performs voluntary movements (intention tremor).

Disease Management

There is currently no cure for mucopolysaccharidosis IIIA. Management of the disease generally involves treating the symptoms and improving the dog's quality of life as much as possible. If you suspect that your dog may have mucopolysaccharidosis IIIA or another disease, you should take your dog to a veterinarian for examination and appropriate advice.

Genetic basis

This disease follows an autosomal recessive mode of inheritance. Autosomal recessive inheritance means that the dog, regardless of sex, must receive two copies of the mutation or pathogenic variant to be at risk of developing the disease. Both parents of an affected dog must carry at least one copy of the mutation. Animals with only one copy of the mutation are not at increased risk of developing the disease, but may pass the mutation on to future generations. Breeding between dogs carrying genetic variants that can cause disease, even if they do not show symptoms, is not recommended.

Technical report

Mucopolysaccharidoses are diseases that affect the ability to degrade different types of mucopolysaccharides. Mucopolysaccharidosis IIIA is caused by the SGSH gene coding for heparan sulfaminidase, specifically, here we analyze the variant c.740_742delCCA that produces a deletion of three base pairs in the gene sequence and affects the folding of the enzyme. The dog must carry two copies of the variant to develop the disease; carriers of one copy of c.740_742delCCA are completely healthy.

Most affected breeds

  • Dachshund


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