Gene and haplotype frequencies of the fourth component of complement (C4) in type 1 diabetics and normal controls.

C4 gene and haplotype frequencies were calculated from phenotype data of 380 unrelated Caucasian patients with insulin dependent (type 1) diabetes mellitus and were compared with analogous frequencies of 382 unrelated healthy Caucasian individuals. In diabetics, a significantly increased frequency of the rare allele C4B 3 (p less than 10(-7] and of the silent alleles C4A Q0 (p less than 10(-7] and B Q0 (p less than 0.002) was observed. Accordingly, insulin dependent diabetes is associated with partial C4 deficiency, which may contribute to the pathogenesis of the disease.

A new partially deficient variant in the phosphoglucomutase 1 system, PGM1*W31.

In a case of disputed paternity an inherited hyposynthetical variant of the PGM1*1A gene was identified. This variant could not be detected by conventional electrophoresis on cellulose acetate membranes but clearly appeared on polyacrylamide gels after isoelectric focusing. The enzyme activity of this variant was about 25% of the normal PGM1*1A protein. The variant was designated PGM1*W31.