Primary hyperoxaluria type II in Burmese, Himalayan and Persian cats

Primary hyperoxaluria is a genetic disorder of glycine metabolism characterized by increased amounts of oxalate in the urine. Excess oxalate accumulates in the blood and deposits in blood vessels, bones and body organs. This condition is called organ oxalosis and can lead to severe organ damage. Clinical manifestations, including azotemia (increased urea and nitrate in the blood) and the formation of urinary stones, appear between 5 and 9 months of age. Acute renal failure with anorexia, dehydration and weakness occurs in cats as young as one year of age. In addition, denervation of motor neurons can lead to muscle atrophy and neurological signs. Clinical manifestations usually result in death of the individual.

The disease is caused by mutation c.507-1G>A in the GRHPR gene, which encodes the enzyme glycoxylate reductase/hydroxypyruvate reductase. The mutation is inherited in an autosomal recessive manner. This means that only individuals who inherit the mutated gene from both parents will develop the disease. Carriers of the mutated gene are clinically healthy but pass the mutation on to their offspring. If two heterozygous individuals are combined, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected.

The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to avoid unintentional breeding of affected individuals.

References:

Gisselman, K., Langston, C., Palma, D., McCue, J. : Calcium oxalate urolithiasis. Compend Contin Educ Vet 31:496-502; quiz 502, 2009. Pubmed reference: 20180219.

Goldstein, RE., Narala, S., Sabet, N., Goldstein, O., McDonough, SP. : Primary hyperoxaluria in cats is caused by a mutation in the feline GRHPR gene. J Hered 100 (Suppl. 1):S2-S7, 2009

Heiene, R., Rumsby, G., Ziener, M., Dahl, S.A., Tims, C., Teige, J., Ottesen, N. : Chronic kidney disease with three cases of oxalate-like nephrosis in Ragdoll cats. J Feline Med Surg 11:474-80, 2009. Pubmed reference: 19095478. 

Osborne, C.A., Lulich, J.P., Kruger, J.M., Ulrich, L.K., Koehler, L.A. : Analysis of 451,891 canine uroliths, feline uroliths, and feline urethral plugs from 1981 to 2007: perspectives from the Minnesota Urolith Center. Vet Clin North Am Small Anim Pract 39:183-97, 2009. Pubmed reference: 19038658