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A new PKLR gene mutation in the R‐type promoter region affects the gene transcription causing pyruvate kinase deficiency
Author(s) -
Manco Licínio,
Ribeiro M. Letícia,
Máximo Valdemar,
Almeida Helena,
Costa Alice,
Freitas Orquídea,
Barbot José,
Abade Augusto,
Tamagnini Gabriel
Publication year - 2000
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.2000.02283.x
Subject(s) - pyruvate kinase deficiency , point mutation , microbiology and biotechnology , biology , gene , mutation , missense mutation , transcription (linguistics) , promoter , pyruvate kinase , coding region , genetics , gene expression , enzyme , biochemistry , linguistics , philosophy , glycolysis
Mutations in the PKLR gene responsible for pyruvate kinase (PK)‐deficient anaemia are mainly located in the coding regions: 11 are in the splicing sites and, recently, three mutations have been described in the promoter region. We now report a novel point mutation A→G on nucleotide 72, upstream from the initiation codon of the PKLR gene, in four Portuguese PK‐deficient patients. This new regulatory mutation occurs within the most proximal of the four GATA motifs (GATA‐A element) in the R‐type promoter region. In two patients who were homozygous for this mutation, a semiquantitative reverse transcription polymerase chain reaction (PCR) procedure was used to evaluate the amount of R‐PK mRNA transcript in the reticulocytes. The mRNA level was about five times lower than in normal controls, demonstrating that the PKLR gene transcription is severely affected, most probably because the −72A→G point mutation disables the binding of the erythroid transcription factor GATA‐1 to the GATA‐A element. Supporting these data, the two patients homozygous for the −72A→G mutation had severe haemolytic anaemia and were transfusion dependent until splenectomy. Two other patients who were compound heterozygous for this mutation and the previously described missense mutation 1456C→T had a mild condition.