Primary Hyperoxaluria

 

Gene: AGXT

Transmission: Autosomal recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease. Both parents of an affected animal must be carriers of at least one copy of the mutation. Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Substitution, AGXT gene; c.996 G>A, p.(G102S), exon2

Medical system: Renal

Breeds: Coton de Tulear

Age of onset of symptoms: 3 to 4 weeks of age

Primary Hyperoxaluria of the Coton de Tuléar is an autosomal recessive genetic disease that affects the urinary system.  The mutation within the AGXT gene results in an enzyme defect in the production of glyoxylate, a small molecule involved with fatty acid and carbohydrate metabolism. This in turn leads to an accumulation of oxalate in the urine (hyperoxaluria) and the precipitation of calcium oxalate crystals which can result in kidney and bladder stone formation.  Affected puppies are often presented to the veterinarian around 3 to 4 weeks of age for abdominal pain, urinary tract obstruction and kidney failure due to the presence of kidney stones.  Affected puppies are often euthanized for humanitarian reasons before the age of 2 months.

 

References:

OMIA link: [1672-9615]

Vidgren G, Vainio‐Siukola K, Honkasalo S, et al. (2012) Primary hyperoxaluria in Coton de Tulear. Animal genetics, 43(3), 356-361. [pubmed/22486513]

Danpure CJ, Jennings PR, Jansen JH.  (1991) Enzymological characterization of a putative canine analogue of primary hyperoxaluria type 1. Biochim Biophys Acta 1096:134-8.  [pubmed/1672096]

 

Contributed by: Emily Morgan, Class of 2020, Faculty of Veterinary Medicine, University of Montreal.