Triosephosphate Isomerase Gene not Localized on the Short Arm of Chromosome 5 in Man

Abstract

THE assignment of the gene for triosephosphate isomerase (TPI, EC 5.3.1.1) on the short arm of chromosome 5 (ref. 1) needs confirmation. Sparkes et al.¹ reported diminished activities of TPI in the heterozygous range in a patient with a partial deletion of the short arm of chromosome 5 (cat cry syndrome). Both her parents, however, had normal values of this enzyme and were considered homozygous normal for the TPI gene. The authors concluded that the patient may have been hemizygous for TPI owing to loss of one TPI locus with the deleted chromosomal region. We now report data on five patients with the same chromosome deletion and normal activities of TPI.