Betaine METABOLISM OF PATIENTS With Homocystinuria

Oral treatment with betaine is conventionally used for patients with inherited homocystinurias. These conditions include a first group of patients with a cystathionine β-synthase (CBS) deficiency and a second group of patients with remethylation defects. The aim of betaine therapy is to reduce level of total plasma homocysteine. Daily dosages and rhythm of administration proposed in the literature vary between 100 to 250 mg / kg / d in 2 to 4 doses. These dosages are not based on validated data and several publications mention much higher dosages particularly when total homocysteine is not controlled. These practices may be unnecessary or even detrimental given the fact that high doses of betaine could for example lead to secondary folate deficiency.