Cystinuria-Associated Marker (Type 3)

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Related Terms: Androgen Dependent Cystinuria

Type: DNA

Sample Types: Fresh EDTA blood or Cheek brushes/swabs

Aminoaciduria and stone formation only observed in intact male dogs. Age of onset of aminoaciduria ranges between 8 months and 2.5 years. First instances of clinical signs (due to stone formation) can range from 1 year to late in life (as late as 9 years observed to date).

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Cost: $65.00

Species and Breeds
Canine - Bulldog (English)
Canine - French Bulldog
Canine - Mastiff, English

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Hematuria, stranguria, urinary obstruction, cystine crystalluria and urolithiasis in intact males only. Females are asymptomatic.

Some affected dogs have been observed to block repeatedly, but there are no studies to determine the effect on lifespan.

Androgen dependent

Histological changes are largely dependent on the extent of blockage and crystal formation. These can range from thickened bladder wall with invasion of inflammatory cells to nephritis.

Unpublished

Explanation of Results
Genotype Phenotype Interpretation
2-2 (Homozygous for Disease-Associated Markers) See Interpretation 2-2 (Homozygous for Cystinuria-Associated Markers) dogs have TWO COPIES of the markers associated with cystinuria and cystine stone formation in your dog's breed. An intact male 2-2 dog has the highest risk for forming cystine stones at some time during his adult life. Castration is recommended to drastically reduce the risk of stone formation and to prevent the passing of the disease-causing allele to all offspring. While females will not be cystinuric and have essentially no known risk for cystine calculi formation, they will pass on the disease-associated marker allele (2) to all of their offspring.
1-2 (Heterozygous) See Interpretation 1-2 (Heterozygous Carrier) dogs have one copy of the normal markers and ONE COPY of the markers associated with cystine stone formation in your dog's breed. Urine nitroprusside screening on intact males, starting between one and two years of age, should be performed, since many 1-2 intact male dogs have elevated cystine levels (nitroprusside test positive, NP+), and several have formed cystine stones. Therefore an intact male dog with this 1-2 result and an NP+ result is at intermediate risk for developing cystine stones. Castration is an option for lowering urine cystine levels in 1-2 dogs, thus reducing the risk for cystine stone formation. Both males and females with the 1-2 result can pass on the high-risk marker allele (2) to their offspring.
1-1 (Homozygous for Normal Markers) See Interpretation 1-1 (Homozygous Normal) dogs have two copies for the normal markers and NO COPIES of the markers associated with cystine stone formation in your dog's breed. A male dog with this result has the lowest risk for forming cystine stones. However, we have identified several 1-1 dogs with elevated urinary cystine levels putting them at risk for cystine stone formation. Therefore, we recommend annual urine nitroprusside test screening for intact male dogs starting between one and two years of age.