PREMATURE TERMINATION MUTATIONS IN 2 PATIENTS WITH DEFICIENCY OF LACTATE-DEHYDROGENASE H(B)-SUBUNIT

Two patients with low lactate dehydrogenase (LD) activity were discove red during healthcare examinations and were found to be homozygous for LD-H (heart) subunit deficiency by electrophoretic isoenzyme analysis of serum and erythrocyte hemolysate. The molecular nature of the gene tic mutations was characterized by amplification by the polymerase cha in reaction and DNA sequencing. In one case, a single-base substitutio n (T-->G transversion) at codon 147 of the LD-H(B) gene resulted in a nonsense mutation; in the other case, a deletion of 2 base pairs had o ccurred at codon 139, resulting in a frameshift translation and premat ure termination.