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January 1967

Some Theoretical Considerations in the Treatment of Homocystinuria

Author Affiliations

From the Department of Pediatrics, University of Wisconsin Medical Center, Madison.

Am J Dis Child. 1967;113(1):101-102. doi:10.1001/archpedi.1967.02090160151023

HOMOCYSTINURIA cases are now considered second in number to those of phenylketonuria (PKU). Still the number of cases available to any one investigator for study and treatment is limited.

Two points must be made by way of introduction to a consideration of the treatment of homocystinuria: (1) methionine is not elevated in the blood of all homocystinurics and (2) homocystinuria is in all likelihood differentiated from the clinical condition described as hypermethioninemia in which homocystine is not excreted.

It is quite clear that the enzymic block in homocystinuria is in the enzyme cystathionine synthase, also known as serine dehydrase. This enzyme in the rat is apparently able to act in the conversion of homocystine to cystine in the presence of serine, and can also function in the conversion of serine to pyruvate.1 Suda and co-workers2 have shown that cystine inhibits this enzyme in rat liver and this may

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