Possibility of prenatal diagnosis of hereditary triose phosphate isomerase deficiency

Prenatal diagnosis has been performed on umbilical cord blood of an 18 weeks fetus of heterozygous triosephosphate isomerase (TPI) deficient parents. After excluding maternal blood contamination, TPI activity was measured and found to be 60 per cent of the normal mean whereas the value of glucose-6-phosphate dehydrogenase activity was in the normal range of fetal blood. In addition, the analysis of the characteristics of fetal TPI, i.e. K_m measurements for glyceraldehyde-3-phosphate, heat stability tests and electrophoretic studies, did not show any evidence of a special form of TPI in fetal blood. These results were consistent with the heterozygous state and were confirmed at birth.