No abstract

The isoelectric focusing study of esterase D in Japanese revealed evidence of a new polymorphic allele (EsD7) which is difficult to find by conventional starch gel electrophoresis only. A comparison with the occurrence of a subdivision of EsD2 in Caucasians (EsD5) suggests a remarkable difference in allele distribution of esterase D among races. Quantitative analysis showed a relatively low value of enzyme activity for this new allele. It is therefore emphasized that in addition to conventional electrophoresis, enzyme assay and further detection by isoelectric focusing are essential in analyzing the esterase D system.

We present here the first familial cases (a mother and son) of dominantly inherited retinoblastoma with a 13q14 deletion [46,XY or XX, del(13)(q14.1q21.2)]. Their esterase D activities in red blood cells were as low as 50% of the normal control and the haplotype of esterase D was a type 1-0 in the mother and a type 2-0 in the son. They had peculiar facies characterized by a high forehead, low and broad nasal root, a short and bulbous nose, a long philtrum, and open mouth with a thin upper lip, and prominent earlobes. Chromosome and esterase D analysis should be performed in patients with retinoblastoma even if retinoblastoma seems to be transmitted through an autosomal dominant inheritance. This family indicates that one of the causes of dominantly inherited retinoblastoma is a chromosome deletion of part of the 13q14 band whether it is detectable by chromosome analysis or not.

The distribution of phosphoglucomutase (PGM,) subtypes in human red cells was determined by isoelectric focusing in 218 Japanese samples. Nine common phenotypes were observed corresponding to the following frequencies of the four alleles at the PGM₁ locus: PGM₁¹⁺ 0.6560, PGM₁^1– 0.1170, PGM₁²⁺ 0.1674 and PGM₁^2– 0.0505. In addition, a characterization of the PGM₁⁷sallele was performed. Our results obtained in the present study revealed the possibility that the PGM₁⁷ allele may be differentiated in the two alleles of PGM₁⁷⁺ and PGM₁^7– through an investigation of isoelectric focusing.

Human red cell esterase D was analysed quantitatively in Japanese samples. Among the three esterase D phenotypes there was a significant difference in catalytic activity, with an approximate ratio of 7:5:3 for EsD 1, EsD 2-1 and EsD 2. With a few inter-type individuals, the distribution of their activity values was plotted in a tri-modal curve. These results suggest that the esterase D system in human red cells is qualitatively and even quantitatively controlled by genes.