Breeds Affected: American Staffordshire Terrier
Samples Accepted: Blood, Buccal Swabs
Disease Information: NCL4a is a lysosomal storage disease with a late onset of symptoms, usually affected dogs are 3-5 years of age. Initial symptoms include problems with balance, particularly on hills, stairs, or when shaking the head. Abnormal eye movements and stiffening of the body are also often seen. As the disease progresses, symptoms include difficulty walking, frequent falling, seizures, and behavioural changes. Affected dogs are usually euthanized 1-4 years after diagnosis.
Inheritance Information: NCL4a is autosomal recessive, meaning that animals with two copies of this allele will be affected. Animals with one copy of the gene will be clinically-normal carriers.
The possible genotypes are:
N/N The dog is normal, and cannot produce affected offspring.
N/ncl4a The dog is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/nlc4a carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
ncl4a/ncl4a The dog is affected. If bred to a normal animal, 100% of the offspring will be carriers. If bred to an N/nlc4a carrier, 50% of the offspring will be carriers and 50% will be affected.
– Carriers may be bred to normal animals (N/ncl4a x N/N) without any risk of producing affected offspring. The offspring should be tested before breeding to determine if they are carriers or normal.
– Breeding two carriers (N/ncl4a x N/ncl4a) is not recommended due to the possibility of 25% of the offspring being affected.
– Affected animals (ncl4a/ncl4a) should not be used for breeding.
Test Information: This mutation test identifies a single base change in exon 2 of the ARSG gene.
Abitbol, M., Thibaud, J.L., Olby, N.J., Hitte, C., Puech, J.P., Maurer, M., Pilot-Storck, F., Hédan, B., Dréano, S., Brahimi, S., Delattre, D., André, C., Gray, F., Delisle, F., Caillaud, C., Bernex, F., Panthier, J.J., Aubin-Houzelstein, G., Blot, S., Tiret, L.:A canine Arylsulfatase G (ARSG) mutation leading to a sulfatase deficiency is associated with neuronal ceroid lipofuscinosis. Proc Natl Acad Sci U S A 107:14775-80, 2010. Pubmed reference: 20679209. Doi: 10.1073/pnas.0914206107.
Further information is available at the Online Mendelian Inheritance in Animals website.