This Article  • References  • Full text PDF  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Contact me when this article is cited  Related Content  • Similar articles in JAMA  Social Bookmarking   What's this?

H. L. Newbold, MD
New York, NY

JAMA. 1989;262(11):1468.

	Since this article does not have an abstract, we have provided the first 150 words of the full text PDF and any section headings.

To the Editor. —

The April 7 JAMA article by Drs Lawhorne and Ringdahl¹ ignores vitamin B₁₂ dependency disorders and thus may leave readers with the false impression that only patients with low serum vitamin B₁₂ levels require the administration of cyanocobalamin. Patients suffering from vitamin B₁₂ dependency disorders do not thrive without extra amounts of the vitamin.

The Merck Manual² states: "Several specific disorders of cobalamin-dependent metabolism have been reported. In each there is some defect either in (1) cellular uptake of the vitamin precursor, (2) conversion of the vitamin to the coenzyme form, or (3) coenzymeapoenzyme interaction.... These disorders usually respond to massive doses of vitamin B-12 (1000 mcg/day IM)."

Rosenberg³ reported on vitamin B₁₂ dependency disorders, and I have published an article correlating psychological tests scores with serum vitamin B₁₂ levels in eight patients suffering from vitamin B₁₂ dependency . . . [Full Text PDF of this Article]

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter     What's this?