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T Soni

Publications and source records attributed to T Soni.

22 records · Page 2Linked to original sources

The Philadelphia variant of galactokinase: impaired [1-14C]galactose oxidation by intact erythrocytes.

Probands with the Philadelphia variant of galactokinase (GALKP) are black people who exhibit reduced galactokinase (GALK) activity in their red blood cells (RBC), but normal activity in their white blood cells (WBC). This reduced RBC GALK was demonstrated in disrupted erythrocytes. To investigate the possibility of a missing cofactor in hemolysates from individuals with GALKP phenotype, we compared [1-14C]galactose oxidation by intact erythrocytes, with the direct GALK assay in disrupted erythrocytes. The rate of [1-14C]glucose oxidation was also measured in order to differentiate an impaired galactose metabolism from a defect further along the pentose phosphate pathway. A good correlation (p less than 0.001) was found between the direct GALK assay and [1-14C]galactose oxidation in control subjects, which indicates that this method can be used effectively for the detection of GALK defects. This was further supported by studies on samples from heterozygotes and homozygotes for the GALKG deficient gene. For all the probands with a GALKP phenotype, diminished CO2 production from galactose was observed in the absence of impaired glucose metabolism. This allowed us to confirm the existence of a GALK deficiency in intact erythrocytes due to the GALKP variant. Further studies of RBC GALK catalytic properties are needed to investigate the molecular basis of this GALK deficiency.

Blood Glucose↗

Screening of the Philadelphia variant of galactokinase in racially unmixed black Africans: first results.

In previous reports, it was emphasized that the gene GALKA of galactokinase was the predominant allele in white populations and that another allele, GALKP, which reduces red blood cell activity (RBC GALK), was common in black people. In a group of black Americans living in Philadelphia, the frequency of GALKA was found to be very close to values expected from independent estimation of white admixture. The authors have suggested that the ancestors of these blacks might have been virtually all GALKP homozygous. We have looked for carriers of GALKP genotypes among 73 black Africans; only 33 probands were shown to have a low RBC GALK. To detect white admixture, immunoglobulin allotypes Km and Gm were investigated in 50 individuals of the sample; 15 GALKP carriers with low RBC GALK and 30 of 35 individuals with normal RBC GALK shared Gm phenotypes exclusive to blacks. Our work demonstrates for the first time the polymorphism of GALK in black Africans in the absence of white admixture.

Africa↗