Hereditary xanthinuria in a goat.

Area of Science:

• Veterinary Medicine
• Animal Genetics
• Biochemistry

Background:

• Xanthine urolithiasis, a rare condition, has not been previously documented in goats.
• Understanding the genetic basis of metabolic disorders in livestock is crucial for herd health management.

Observation:

• A 2-year-old goat presented with anorexia, weight loss, severe azotemia, and ultrasound findings indicative of kidney and ureteral abnormalities.
• Necropsy revealed small kidneys with dilated pelves and nephroliths composed entirely of xanthine.
• Histopathology confirmed tubular distension with xanthine crystals.

Findings:

• Genetic sequencing identified a heterozygous XDH p.Leu128Pro variant and a homozygous MOCOS p.Asp303Gly variant in the affected goat.
• The XDH variant was absent in control populations, while the MOCOS variant had a low allele frequency.
• The MOCOS variant alone could be causal, or a combination of variants may be responsible for the observed xanthinuria.

Implications:

• This case provides the first evidence of hereditary xanthinuria in goats, suggesting a potential genetic predisposition.
• Further functional studies are required to definitively identify the causal genetic variant(s) and understand the inheritance pattern.
• Findings contribute to the knowledge of urolithiasis in small ruminants and genetic disease in goats.