Guest guest Posted September 27, 2004 Report Share Posted September 27, 2004 Rather than pursue this, I suggest everyone interested get theirs tested and do what the doc prescribes. It's a medical issue created probably genetically. Goldman: Cecil Textbook of Medicine, 21st ed. ETIOLOGY. The classic form of homocystinuria is cystathionine beta-synthase deficiency, which results in decreased transulfuration and hypermethioninemic hyperhomocyst(e)inemia. Homocystinuria may also result from defective remethylation, as in a deficiency of methylenetetrahydrofolate reductase, or from a disorder of the delivery, generation, or utilization of the methylcobalamin cofactor of methionine synthase. Defects of remethylation give rise to hyperhomocyst(e)inemia with normal or low methionine. All these disorders are inherited in an autosomal recessive manner (Table 213-1) .INCIDENCE AND PREVALENCE. Minimum estimates of the incidence of cystathionine beta-synthase deficiency by newborn screening programs have ranged from 1:300,000 to 1:60,000 live births, varying with the population and method. Estimates of its incidence in Europe have been in the range of 1:40,000, which corresponds to a carrier (heterozygote) frequency of about 1%. The incidence of severe homocysteine remethylation defects appears to be less than 1:500,000. On the other hand, partial remethylation deficiencies seem to have a much greater incidence, which may be clinically relevant in predisposing individuals to thrombotic disorders; evidence of deficiency has been reported in 15 to 30% of some series of patients presenting with vaso-occlusive disease." TABLE 213-1 -- GENETIC DEFECTS ASSOCIATED WITH HOMOCYSTINURIA FUNCTIONAL DEFECT COMMON NAME ENZYME DEFECT CHROMOSOME LOCUS Transulfuration "Classic" homocystinuria Cystathionine beta-synthase 22q22.3 Remethylation Folate-dependent homocystinuria Methylenetetrahydrofolate reductase 1p36.3 Cbl G Methionine synthase (methyltransferase) 5p15.2-p15.3 Cbl E Methyltransferase reductase 1q43 Cobalamin transport TC-II Transcobalamin II 22q11-q13.1 Cbl F Lysosomal B12 translocase -- Cobalamin reductase Cbl C, Cbl D Unknown -- Regards. ----- Original Message ----- From: bpinfo@... Sent: Sunday, September 26, 2004 8:47 PM Subject: Re: [ ] Re: obsessive behavior In a message dated 9/26/04 8:26:19 PM Eastern Daylight Time, perspect1111@... writes: Isn't the current 'standard' method for lowering homocysteine increasing B-6, B-12 and folic acid?Yer certainly do not want higher than average homocysteine, at least according to the people at Tufts ........ Bloomberg et al.Let's not forget the doctor at Harvard (some 25-30 years ago) named McCully, who noticed severe atherosclerosis in some very young patients, amybe 2 or 3 years old. They also had very high homocysteine. Because he advocated folate (and the other associated B vitamins) as a preventive to CVD, he was driven out of Harvard. It took a long time for him to be vindicated.I think of that every time that I see Harvard being touted as an authoritative source of opinion on anything.-- Ken Quote Link to comment Share on other sites More sharing options...
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