Hyperoxaluria

An hereditary disorder that causes a special type of stone to form in the kidney and the urine beginning in childhood. Also known as oxalosis. The clinical features of this disease include the following: {{}}Urinary tract: Stones in the urine and kidney that are composed of calcium oxalate and lead to kidney failure. Cardiovascular: Heart block, insufficiency with spasm and even blockage of arteries. Skin: Livedo reticularis (marble-like mottling) and acrocyanosis (blueness of the fingers and toes). Skeleton: Pathologic fractures (bone breaks with minimal, if any, trauma). Eyes: Optic neuropathy (optic nerve disease). A key laboratory finding is deficiency of an enzyme called peroxisomal alanine: glyoxylate aminotransferase, the biochemical basis of this disease. Another key lab finding is continuous high urinary excretion of oxalate. Inheritance of the disease is autosomal recessive with two separate loci. This means that the genes for this disease are on autosomes (non-sex chromosomes) and that parents carry one copy of such a gene and that the chance for each of their children to receive both of their genes and have the disease is 1 in 4 (25%). By "two loci" is meant that there are two genes at different spots in the human genome that are capable of causing this disease. Mutations at these two spots perturb the molecular system of protein "ZIP codes" and have been found to cause hyperoxaluria. The course of the disease has usually been relentless, leading to death in childhood or early adult life.

* * *

Presence of an unusually large amount of oxalic acid or oxalates in the urine; renal stones may occur. SYN: oxaluria.

- primary h. and oxalosis [MIM*259900 & MIM*260000] a metabolic disorder, usually evident clinically in the first decade of life, characterized by calcium oxalate nephrocalcinosis and nephrolithiasis, extrarenal oxalosis, and increased urinary output of oxalic and glycolic acid s, leading to progressive renal failure and uremia. Type I is due to a deficiency in alanine-glyoxylate aminotransferase and type II to a deficiency in D-glycerate dehydrogenase; the latter is a milder disease with a better long-term prognosis for renal function. Both types are inherited as autosomal recessive, caused by mutation in the alanine-glyoxylate aminotransferase gene (AGXT) on 2q.

* * *

hy·per·ox·al·uria .hī-pə-.räk-sə-'lu̇r-ē-ə n the presence of excess oxalic acid or oxalates in the urine called also oxaluria

* * *

hy·per·ox·al·uria (hi″pər-ok″sə-luґre-ə) the excretion of an excessive amount of oxalates in the urine; high concentrations of oxalates may lead to formation of urinary calculi. Called also oxaluria.