Hereditary xanthinuria and urolithiasis in a domestic shorthair cat

Abstract

A 2-year-old domestic shorthair cat was presented with a history of hematuria, stranguria and intermittent urethral obstruction. Urine sediment showed hematuria, pyuria, and yellow-brown, amorphous and spherical crystals. Upon surgical correction of the obstructed urethra by perineal urethrostomy, many dark yellow to grey, irregular, gravel-like to millet grain-sized uroliths, consisting of 100% xanthine by crystallography were found. The urinary xanthine concentration was high. The cat subsequently developed bilateral nephroliths, recurrent urinary tract infection, and chronic kidney failure. Dietary management with a low-purine diet failed in part due to poor compliance, and the cat was euthanized at 6 years of age. Xanthinuria is rare inborn error of metabolism in cats and other species but should be considered as a differential diagnosis in cases of feline urolithiasis. No associated molecular genetic defect has been elucidated, and management of these cases is difficult. In the absence of calculi for analysis, measuring urinary xanthine concentration can help in diagnosing this metabolic defect.

Hereditary xanthinuria in a goat

“…Hereditary xanthinuria has been reported in cats (OMIA 001283‐9685), dogs (OMIA 001283‐9615), and cattle (OMIA 001819‐9913) . In some reports, the genetic basis was established by sequencing; in other cases, a primary cause was presumed after eliminating a history of XDH inhibitor use . Similar to the goat in our study, many of the other domestic species with hereditary xanthinuria had severe disease characterized by a juvenile or young adult onset, nephrolithiasis, and renal pathology …”

“…Specifically, a study on sheep with xanthine calculi concluded that low dietary molybdenum could be causative because of molybdenum's role in purine metabolism . Hereditary xanthinuria has been reported in cats (OMIA 001283‐9685), dogs (OMIA 001283‐9615), and cattle (OMIA 001819‐9913) . In some reports, the genetic basis was established by sequencing; in other cases, a primary cause was presumed after eliminating a history of XDH inhibitor use .…”

Possibilities of urolithiasis crystallodiagnostics

“…A specificity of healthy animals' metabolism is urine saturation with organic and non-organic crystal forming substances, able to form concrements in urolithiasis (1,3,16). Those characteristics provide diagnostically meaningful changes of crystallogenic properties and initiating potential of cat's urine, that was expressed in statistically significant shifting of particular biomedium's "tesiocrystalloscopic pattern", causing abrupt crystal formation activation (P<0,05 -for number of estimated visuametric parameters).…”

“…Nowadays, one of the most common groups of diseases in veterinary medicine is the urinary system pathology (1,2). This fact can be confirmed by increasing number of owners of pets with urolithiasis, looking for help in veterinary clinics (3,4). Urolithiasis is widespread disease, could be found in many species, including cats, dogs, rabbits, guinea-pigs, turtles etc (1,(4)(5)(6).…”

“…Common methods, using in urolithiasis diagnostic process include (2,3,8,11,12): Clinical evaluation, when some urolithiasis distinctive symptoms (as ischuria, dysuria, pollakiuria, hematuria, hemoglobinuria, leukocyturia, proteinuria) can be revealed. It's important to note, that during clinical evaluation only deep disorders in urinary system can be seen.…”