Cystathioninuria

Cystathioninuria
Other namesCystathionase deficiency
Cystathionine
SpecialtyMedical genetics

Cystathioninuria, also called cystathionase deficiency, is an autosomal recessive[1] metabolic disorder. It is characterized by an abnormal accumulation of plasma cystathionine leading to excess cystathionine in the urine. Hereditary cystathioninuria is associated with the reduced activity of the enzyme cystathionine gamma-lyase.[2] It is considered a biochemical anomaly. This is because it associated with a wide range of diseases and its inconsistency.

Cystathionase catalyzes cystathionine to cysteine and α-ketobutyrate.[3] Cysteine is an essential amino acid and its conversion from cystathionine occurs in the trans-sulfuration pathway. The availability of cysteine is necessary for the synthesis of an important anti-oxidant, glutathione.[2] Cystathionase has a co-enzyme, pyridoxal phosphate, which is the active form the vitamin B6. This means that vitamin B6 is essential for the function of cystathionase.

Cystathioninuria can be broken down into two main categories. Primary cystathioninuria is caused by the recessive inherited deficiency of cystathionase enzyme.[4] Secondary cystathioninuria is described by non-genetic conditions of excess cystathionine. Secondary cystathioninuria includes temporary excess cystathionine of premature infants, severe generalized liver damage, thyrotoxicosis, hepatoblastoma, or neuroblastoma.[4] Cases of secondary cystathioninuria are not responsive to vitamin B6 administration.[3]

  1. ^ Online Mendelian Inheritance in Man (OMIM): 219500
  2. ^ a b Wang, Jian; Hegele, Robert (April 2003). "Genomic basis of cystathioninuria (MIM 219500) revealed by multiple mutations in cystathionine gamma-lyase (CTH)". Human Genetics. 112 (4): 404–8. doi:10.1007/s00439-003-0906-8. PMID 12574942. S2CID 37114507.
  3. ^ a b Scott, Ronald; Dassell, Steven; Clark, Sandra; Chiang-Teng, Cecilia; Swedberg, Kathryn (April 1970). "Cystathioninemia: A benign genetic condition". Journal of Pediatrics. 76 (4): 571–577. doi:10.1016/S0022-3476(70)80407-3. PMID 5420794.
  4. ^ a b Rajnerc, J.R.; Gennip, A.H.; Abeling, N.G.G.M.; van der Zee, J.M.; Voute, P.A. (1984). "Cystathioninuria in patients with neuroblastoma". Medical and Pediatric Oncology. 12 (2): 81–4. doi:10.1002/mpo.2950120203. PMID 6422219.