Homocystinuria
An inherited metabolic disorder causing accumulation of homocysteine, often leading to thrombotic complications if untreated.
Homocystinuria (HCU) is a rare inherited metabolic disorder that prevents the normal breakdown of protein.[1] A child must receive one copy of the faulty gene from each parent to be affected, as homocystinuria follows an autosomal recessive inheritance pattern.[2]
Quick Facts
- Type
- Inherited metabolic disorder
- Cause
- Deficiency of cystathionine beta synthase or methionine synthase; also vitamin B6, B12, or folate deficiency
- Inheritance
- Autosomal recessive
- Treatment
- Vitamin B6
- folic acid
- betaine
- low-methionine diet
- Prognosis
- Reduced life expectancy if untreated; approximately 50% experience thrombotic complications before age 30
Facts from the source article.
Key facts and history
No specific cure has been discovered for homocystinuria.[3] Many people are treated with high doses of vitamin B6, and slightly less than 50% respond to this treatment.[3] For patients with cystathionine beta-synthase deficiency who do not respond to B6, low-protein food is recommended.[4] One theory proposes that the pharaoh Akhenaten may have had homocystinuria.[5][6]
This theory was published by Mislav Čavka and colleagues in Collegium antropologicum in March 2010.[5]
What the research sources say
The laboratory analysis of homocysteine is complicated because most of it is bound to other thiol amino acids and proteins as disulphides.[7] Total homocyst(e)ine analysis requires reduction of all disulphide bonds before analysis, traditionally by HPLC after derivatisation.[7] Measuring the total homocysteine level (both free and bound) is valuable for both confirming the diagnosis and tracking how well treatment is working.[7] Methionine is a metabolite that is incorporated into the screening panels of numerous newborn testing programs.[8]
Standard metabolic biochemistry tests can identify a CBS deficiency.[8] Elevated methionine levels and the detection of homocysteine are common findings when analyzing amino acids in plasma or urine.[8] Known genetic mutations can be identified through the application of genetic testing.[8]
References
- "Homocystinuria", 9 May 2018. facts only, no text reused. nhs.uk
- Wikipedia, "Homocystinuria" (CC BY-SA 4.0), which cites: "Homocystinuria", 9 May 2018; Tao, "First aid for the USMLE step 1 2020 : a student-to-student guide", 2020-01-02 (we also read that source) en.wikipedia.org
- Wikipedia, "Homocystinuria" (CC BY-SA 4.0), which cites: Bakker, "Hyperhomocysteinaemia and associated disease", Pharmacy World & Science, June 1997, p. 126–132 (original not read by us) en.wikipedia.org
- Wikipedia, "Homocystinuria" (CC BY-SA 4.0), which cites: Sacharow, "Homocystinuria Caused by Cystathionine Beta-Synthase Deficiency", GeneReviews®, 1993 (original not read by us) en.wikipedia.org
- "Homocystinuria, a possible solution of the Akhenaten's mystery", Coll Antropol., Mar 2010, p. 255–58. facts only, no text reused. hrcak.srce.hr
- Wikipedia, "Homocystinuria" (CC BY-SA 4.0), which cites: "Homocystinuria, a possible solution of the Akhenaten's mystery", Coll Antropol., Mar 2010, p. 255–58 (we also read that source) en.wikipedia.org
- Wikipedia, "Homocystinuria" (CC BY-SA 4.0), which cites: Carducci, "Automated high-performance liquid chromatographic method for the determination of homocysteine in plasma samples", Journal of Chromatography A, 1999, p. 93–100 (original not read by us) en.wikipedia.org
- Wikipedia, "Homocystinuria" (CC BY-SA 4.0), which cites: "Physician's guide to the laboratory diagnosis of metabolic diseases; with 270 tables", Springer, 2005; Refsum, "Facts and Recommendations about Total Homocysteine Determinations: An Expert Opinion", Clinical Chemistry, 2004, p. 3–32 (we also read that source) en.wikipedia.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Homocystinuria (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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