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Primary hyperoxaluria type 2


Other Names for this Disease
  • D-glycerate dehydrogenase deficiency
  • Glyceric aciduria
  • Glyoxylate reductase/hydroxypyruvate reductase deficiency
  • HP2
  • Oxalosis 2
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Overview



What is primary hyperoxaluria type 2?

What are the signs and symptoms of primary hyperoxaluria type 2?

What causes primary hyperoxaluria type 2?

How is primary hyperoxaluria type 2 inherited?


What is primary hyperoxaluria type 2?

Primary hyperoxaluria type 2  is a rare condition characterized by the overproduction of a substance called oxalate (also called oxalic acid). In the kidneys, the excess oxalate combines with calcium to form calcium oxalate, a hard compound that is the main component of kidney stones. Deposits of calcium oxalate can lead to kidney damage, kidney failure, and injury to other organs. Primary hyperoxaluria type 2 is caused by the shortage (deficiency) of an enzyme called glyoxylate reductase/hydroxypyruvate reductase (GRHPR) that normally prevents the buildup of oxalate. This enzyme shortage is caused by mutations in the GRHPR gene. Primary hyperoxaluria type 2 is inherited in an autosomal recessive pattern.[1]
Last updated: 1/3/2013

What are the signs and symptoms of primary hyperoxaluria type 2?

Primary hyperoxaluria type 2 is characterized by recurrent nephrolithiasis (deposition of calcium oxalate in the kidney and urinary tract), nephrocalcinosis (deposition of calcium oxalate in the kidney tissue), and end-stage renal disease (ESRD). After ESRD, oxalosis (widespread tissue deposition of calcium oxalate) usually develops. Presenting symptoms are typically those associated with the presence of kidney stones, including hematuria, renal colic (a type of abdominal pain caused by kidney stones), or obstruction of the urinary tract.[2] The symptoms of primary hyperoxaluria type 2 are typically less severe than primary hyperoxaluria type 1 and may be limited to kidney stone formation. Symptom onset may occur in childhood or adolescence.[2][3] End stage renal disease is rarely observed in childhood.[3]
Last updated: 1/3/2013

What causes primary hyperoxaluria type 2?

Researchers have identified more than a dozen GRHPR mutations that cause this condition.[2][4] These mutations either introduce signals that disrupt production of the glyoxylate reductase/hydroxypyruvate reductase enzyme or alter its structure. As a result, enzyme activity is absent or dramatically reduced. Glyoxylate builds up because of the enzyme shortage, and is converted to a compound called oxalate instead of glycolate. Oxalate, in turn, combines with calcium to form calcium oxalate, which the body cannot readily eliminate. Deposits of calcium oxalate can lead to the characteristic features of primary hyperoxaluria type 2.[4]
Last updated: 1/3/2013

How is primary hyperoxaluria type 2 inherited?

Primary hyperoxaluria type 2 is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.[1]
Last updated: 1/3/2013

References
  1. Primary hyperoxaluria. Genetics Home Reference (GHR). January 2008; http://ghr.nlm.nih.gov/condition/primary-hyperoxaluria. Accessed 1/2/2013.
  2. Rumsby G. Primary Hyperoxaluria Type 2. GeneReviews. May 2011; http://www.ncbi.nlm.nih.gov/books/NBK2692/. Accessed 1/2/2013.
  3. Leumann E, Hoppe B. The Primary Hyperoxalurias. JASN. September 1, 2001 ; http://jasn.asnjournals.org/content/12/9/1986.long. Accessed 1/2/2013.
  4. GRHPR. Genetics Home Reference (GHR). January 2008; http://ghr.nlm.nih.gov/gene/GRHPR. Accessed 1/2/2013.