Homocystinuria

Homocystinuria (Homocystinuria) is an autosomal recessive amino acid metabolic disorders. Mainly due to the "cystathionine synthase (Cystathionine-β-synthase)" function lacks, causing high homocysteine ​​(Homocysteine) Synthesis of cystine (Cystine; Cys) dysfunction occurs during the in vivo accumulation of A sulfur acid (Methionine; Met), high homocysteine ​​(Homocystine; Hcy), homocysteine ​​disulfide compounds and compound (Mix Disulfide) and other abnormal metabolites.

First, clinical symptoms and incidence
The disease incidence in Europe and whites about 1/200000, Taiwan, the incidence is very low, the majority of cases is a high methionine hypertriglyceridemia, in recent years, Taipei Veterans General Hospital found that Aboriginal Lanyu a higher incidence of homocystinuria. Excreted in the urine of patients by the large number of high homocysteine, if not treated early, may have mental retardation, skeletal deformities, dislocation of the eye lens, cardiovascular disease and thrombosis and other clinical symptoms.

Second, treatment and prognosis
Some high homocysteine ​​in patients taking high doses of vitamin B6 (Vit B6), the blood and urine of high methionine cystine is reduced. Another study reported that oral administration of betaine (Betain) can be transformed into high homocysteine ​​methionine. When the patient's dose of vitamin B6 reaction, treatment with oral vitamin B6, and combined vitamin B12, folic acid (Folic Acid) and supplemental betaine; when patients doses of vitamin B6 added to 1000 mg / day there is still no reaction , should start with a low methionine diet dietary control treatment, and taking supplemental cysteine ​​and betaine. Regular ISR blood and urine methionine high homocysteine ​​and cardiovascular division ophthalmology and consultation in order to understand the control of efficacy.
In general, if the diet-controlled cases, the prognosis is not very satisfactory. If caught and treated early, intelligence is not normally damage is too severe, but the eyes of the lesions are more difficult to avoid, control survived rigorous, sequelae are also relatively more light.

Third, screening and diagnostic methods
Newborn screening method is to measure the paper sheet specimen of blood content of methionine, when the blood concentration greater than 60μM (1 mg / dL) should further review; rising if the concentration of methionine in the phenomenon of which should confirm the diagnosis. However, to be screened with A thiamine likely to cause false negative in recent years has been the development of other screening methods (such as: the MS / MS quantitation high blood film specimens homocysteine ​​levels) to assist screening sensitivity. Confirm the diagnosis in addition to the clinical assessment of pediatric specialist, the laboratory confirmation method for the analysis of blood and urine related to the content of amino acids, or the direct determination of epidermal cells "cystathionine synthase 'activity, combined with gene Mutation analysis.