OBJECTIVETo screen potential mutation and explore the underlying mechanism for a consanguineous pedigree featuring pyruvate kinase (PK) deficiency.

METHODSThe red blood cell pyruvate kinase activities of all family members were detected. All the exons and intron-exon boundaries of the PKLR gene for the proband were amplified and analyzed by direct sequencing. Restriction endonuclease enzymes were used to identify the presence of mutations of all family members.

RESULTSThe pyruvate kinase activities were 5.89 U/g Hb in the proband, 3.45, 6.54, 8.87, 7.89, 9.32 U/g Hb in his younger sister, father, mother, grandmother and elder aunt, respectively. The homozygous missense mutation of T>C transition at position 941 in exon 7 of PKLR gene resulted to a Ile314Thr substitution in the proband, and mutant alleles were identified at the level of RNA transcript by cDNA sequence analysis. His younger sister was also homozygous for Ile314Thr. Heterozygosity for Ile314Thr was confirmed in his grandmother, parents and elder aunt.

CONCLUSIONIle314Thr homozygous missense mutation in exon 7 of PKLR is the molecular mechanism of pyruvate kinase deficiency in this family.