Hereditary xanthinuria type 1(XAN1)

MedGen UID:: 82771
•Concept ID:: C0268118
•: Disease or Syndrome

Synonyms:	XAN1; Xanthinuria type 1; Xanthinuria, Type I; XDH deficiency
SNOMED CT:	Deficiency of hypoxanthine oxidase (124147007); Deficiency of xanthine oxidase (124147007); Hereditary xanthinuria type 1 (836343001); Xanthinuria type I (836343001); Xanthine oxidase deficiency (124147007)
Modes of inheritance:	Autosomal recessive inheritance MedGen UID: 141025 •Concept ID: C0441748 • Intellectual Product Source: Orphanet A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Autosomal recessive inheritance (Orphanet)

Gene (location): Gene(s) directly associated with this condition or phenotype.	XDH (2p23.1)

Monarch Initiative:	MONDO:0010209
OMIM®:	278300
Orphanet:	ORPHA93601

Definition

Xanthinuria, which was first described by Dent and Philpot (1954), is characterized by excretion of large amounts of xanthine in the urine and a tendency to form xanthine stones. Uric acid is strikingly diminished in serum and urine. Two clinically similar but distinct forms of xanthinuria are recognized. In type I (XAN1) there is an isolated deficiency of xanthine dehydrogenase, and in type II (XAN2; 603592) there is a dual deficiency of xanthine dehydrogenase and aldehyde oxidase (603592). Type I patients can metabolize allopurinol, whereas type II patients cannot (Simmonds et al., 1995). Xanthinuria also occurs in molybdenum cofactor deficiency (252150). Type II xanthinuria is caused by mutation in the MOCOS gene (613274), which encodes the enzyme that sulfurates the molybdenum cofactor for XDH and AOX1 (602841). [from OMIM]

Additional description

From MedlinePlus Genetics
Hereditary xanthinuria is a condition that most often affects the kidneys. It is characterized by high levels of a compound called xanthine and very low levels of another compound called uric acid in the blood and urine. The excess xanthine can accumulate in the kidneys and other tissues. In the kidneys, xanthine forms tiny crystals that occasionally build up to create kidney stones. These stones can impair kidney function and ultimately cause kidney failure. Related signs and symptoms can include abdominal pain, recurrent urinary tract infections, and blood in the urine (hematuria). Less commonly, xanthine crystals build up in the muscles, causing pain and cramping. In some people with hereditary xanthinuria, the condition does not cause any health problems.

Researchers have described two major forms of hereditary xanthinuria, types I and II. The types are distinguished by the enzymes involved; they have the same signs and symptoms. https://medlineplus.gov/genetics/condition/hereditary-xanthinuria