Genetic test for type II-A cystinuria in the Australian Cattle Dog: it detects the SLC3A1 deletion c.1098_1103del (p.T367_T368del), dominantly inherited, associated with a defect in renal cystine reabsorption with urolithiasis and risk of urinary obstruction. The molecular test is complementary —not substitutive— to urinalysis and stone analysis.

Applicable breed: Australian Cattle Dog (the only breed described, OMIA:001879). Limited population data.

- Recurrent cystitis, hematuria, strangury (males and females)
- Hexagonal cystine crystals in sediment or cystine stones
- Partial or complete urinary obstruction
- Possible renal failure in unresolved obstructions

Brons et al. (2013) identified an in-frame 6-bp deletion in exon 6 of SLC3A1 as the cause of cystinuria in the Australian Cattle Dog, within their new I/II/III classification. Cystinuria type II-A, OMIA:001879; the only breed described.

- Do not breed from affected animals (neither hetero- nor homozygotes): 50% of the offspring inherit the variant
- Test breeding animals before mating; only a clear×clear mating avoids transmitting the variant to the offspring
- Prophylaxis: high hydration, alkaline urine, control of crystalluria
- After a confirmed clinical case, do not repeat the parental mating

Differentiate from recessive type I cystinuria (Newfoundland/Landseer, SLC3A1 c.586C>T) and from androgen-dependent type III (entire males of other breeds: it resolves with castration — not applicable here). Diagnosis: hexagonal crystals in sediment or stone analysis; metabolic screening (nitroprusside, urinary amino acids) detects it before the clinical picture.

1. Brons et al. 2013, SLC3A1/SLC7A9 y nueva clasificación I/II/III incl. Boyero australiano (PMID 24001348)
2. Revisión cistinuria perro y gato 2021 (PMID 34438894)
3. OMIA:001879 Cystinuria, type II-A
4. Lulich et al. 2025, epidemiología de urolitos de cistina (PMID 40298126)