A new variant XXXX allele that is readily detectable in stimulated lymphocytes and lymphoblastoid cell lines but not in circulating lymphocytes or erythrocytes.

@entity1 @entity53179 @entity23909
We describe an allele of the @entity1 glyoxalase GLO locus that encodes an enzymatically inactive form of the protein, which would not have been detected if only circulating erythrocytes and lymphocytes had been studied. The new allele is named GLO*3 and its protein product, GLO 3. Circulating blood cells of @entity53179 /GLO*3 heterozygotes have just one electrophoretic band that migrates as the normal 2-2 dimer. Lymphoblastoid cell lines and phytohemagglutinin-stimulated lymphocytes from the same individuals have two electrophoretic bands, one with the mobility of the 2-2 dimer and one with the mobility of the 2-1 dimer that is present in @entity53179 / @entity23909 heterozygotes, but a band with the mobility of the 1-1 dimer is not present. Therefore, the GLO*3 allele encodes a monomer that has the electrophoretic mobility of @entity23909 but is enzymatically inactive unless it is combined with normal monomers in 2-3 and 1-3 heterodimers. The failure to detect the GLO 3 protein in red cells and unstimulated lymphocytes is attributed to a relatively great instability or small rate of production in those cells. Consistent with this interpretation is the reduction of GLO activity in red cells of @entity53179 /GLO*3 and @entity23909 /GLO*3 heterozygotes to 65% or less of that in normal homozygotes and heterozygotes, while the activity of GLO*3 heterozygous lymphoblastoid cells is about 80% of normal. In contrast, the GLO activity of lymphoblastoid cells that had one copy of the GLO locus deleted by gamma-irradiation was 50%-60% of normal. Our observations indicate that certain kinds of mutant alleles of the GLO locus, and perhaps other loci, may not be detected in electrophoretic surveys on circulating blood cells only. The segregation of alleles that are not expressed in circulating red and white blood cells could confuse attempts to determine parentage, as they might have in the family described here. The observations also demonstrate the feasibility of mapping @entity1 genes by using ionizing radiation to create partial chromosome deletions in cultured cells.
