Mutations in the pyruvate kinase L gene in patients with hereditary hemolytic anemia.

We have completely sequenced the introns of the human L-type pyruvate kinase (PK) gene using the published cDNA sequence. Subsequently, DNA from 12 unrelated PK deficiency (PKD) patients of Central European origin was investigated for mutations in this gene by solid-phase sequencing. We detected 10 different mutations, 9 of which result in single amino acid alterations, whereas the tenth destroys a splice site. Eight of the 10 mutations have not been described before. We found 7 missense mutations: G994-->A (Gly-332-->Ser), G1006-->T (Ala-336-->Ser), A1081-->G (Asn-361-->Asp), G1174-->A (Ala-392-->Thr), G1493-->A (Arg-498-->His), G1529-->A (Arg-510-->Gln), C1594-->T (Arg-532-->Trp), one in-frame triplet deletion (del) as well as one insertion (ins): del AAG1060-62 (del Lys-354), ins AGC after C1203 (ins Ser after Cys-401), and one splice-site mutation at the border of intron A to exon 3: g/G283-->a/G. Although the enzymatic properties are substantially changed in all PK mutations, only two affected amino acid positions are in or close to the active site. Mutations C1594-->T, G994-->A, del AAG1060-62 and the splice-site mutation g/G283-->a/G have been detected in two different patients each. Mutation G1529-->A was found in five different alleles. Haplotype analysis with the A/C polymorphism at position 1705 gave evidence for a single origin of this most frequent mutation in PKD as suggested by Baronciani and Beutler (Proc Natl Acad Sci USA 90:4324, 1993). Carrier detection and prenatal diagnosis are now feasible for the affected families.