Embark for Veterinarians

Applied Clinical Genetics Case Library
Case 9

Signalment & History
  • 6-years-old 
  • Neutered male
  • Purebred Dalmatian
  • No significant history
Presenting Complaint
  • Urinating a lot more frequently within the last two weeks, unable to urinate for the past 24 hours
Physical Exam
  • Full, painful bladder when palpated, but otherwise unremarkable.
  • Obstructed urethra
  • Dalmatians are notorious for making urate stones, but the genetic test confirms clinical suspicion. Are Dalmatians without this genetic mutation (LUA Dalmatians). Also makes the radiographs being negative for stones make sense (can only be seen on ultrasound).
  • U/A
  • CBC/Chem
  • Radiographs
  • Bladder ultrasound
  • U/A – Acidic, precipitate when urine allowed to sit (clinical hyperuricosuria)
  • Bloodwork – Slightly azotemic with high normal potassium. Normal CBC.
    • BUN 90 (7-25), Creatinine 4.2 (0.3-1.4), and K 5.9 (3.7-5.8)
  • Radiographs – No stones visible (urate stones radiolucent)
  • Ultrasound – Multiple stones visible, dilated proximal urethra (suggesting an obstruction)
  • That this is a common problem with Dalmatians, although not all Dalmatians develop stones.
  • This is an emergency situation until we can relieve the obstruction, but once a urinary catheter is in place, he can be managed in the hospital until he is stable enough to have surgery.
  • Very manageable as long as we fix the obstruction and put him on a low protein diet with an additional medication (allopurinol).
  • There is a chance for this to reoccur if he does not stay on the proper diet/medication plan.
  • Sedate patient, place indwelling urinary catheter (Foley)
    • Hospitalize on IV fluids, +/- antibiotics, (depends on the rest of the diagnostics)
  • Perform cystotomy (referral to specialty for ablation – most owners do not opt for this and almost no cystotomy is ever an emergency if you can pass a urinary catheter).
  • Discharge with prescription diet and allopurinol.
  • Post-Sx at-home procedures (minimal activity, make sure isn’t eating too fast, no bathing for 2 wks, etc.)
  • Recheck in 2 weeks for suture removal and in 4 weeks for bladder ultrasound.
  • Monitor with an ultrasound +/- U/A every 6 months depending on response to treatment.
  • Due to recent breeding practices, the variant of the SLC2A9 gene associated with higher risk of HUU is no longer “fixed” in Dalmatians. All Dalmatians are no longer at-risk for HUU; genetic testing can indicate the level of risk. In the 1970s, an outcross was made to a Pointer so that breeders had the option to breed away from the HUU variant. Dogs that are descendants of this line of AKC registerable Dalmatians are known as low uric acid (LUA) Dalmatians. 
  • Unrelated to the outcross program, the HUU variant has since been detected in a number of other breeds including the Bulldog, American Pitbull Terrier, Black Russian Terrier, and American Staffordshire Terrier.
  • Clinical Impact of Genetic Result:
    • Certain genetic variants are classically associated with one breed. However, that variant may appear in many other breeds and cause a similar phenotype. By knowing a dog is at-risk for HUU diagnostics such as ultrasound monitoring, serial urinalyses, and therapeutic diets can be employed before clinical signs develop.