Novel mutations associated with pyruvate kinase deficiency in Brazil

Abstract Background: Pyruvate kinase deficiency is a hereditary disease that affects the glycolytic pathway of the red blood cell, causing nonspherocytic hemolytic anemia. The disease is transmitted as an autosomal recessive trait and shows a marked variability in clinical expression. This study reports on the molecular characterization of ten Brazilian pyruvate kinase-deficient patients and the genotype-phenotype correlations. Method: Sanger sequencing and in silico analysis were carried out to identify and characterize the genetic mutations. A non-affected group of Brazilian individuals were also screened for the most commonly reported variants (c.1456C>T and c.1529G>A). Results: Ten different variants were identified in the PKLR gene, of which three are reported here for the first time: p.Leu61Gln, p.Ala137Val and p.Ala428Thr. All the three missense variants involve conserved amino acids, providing a rationale for the observed enzyme deficiency. The allelic frequency of c.1456C>T was 0.1% and the 1529G>A variant was not found. Conclusion: This is the first comprehensive report on molecular characterization of pyruvate kinase deficiency from South America. The results allowed us to correlate the severity of the clinical phenotype with the identified variants.

Severe hypertriglyceridemia in an infant with red cell pyruvate kinase deficiency.

Severe hypertriglyceridemia has been observed in infants with beta-thalassemia major, an association termed hypertriglyceridemia-thalassemia syndrome. The pathophysiological basis for this association has remained unclear. We describe 6-month-old American girl with red cell pyruvate kinase (PK) deficiency, failure to thrive, and marked hypertriglyceridemia (=1500 mg/dL). The hyperlipidemia resolved with hypertransfusion therapy. At age 18 months she underwent a splenectomy and has remained transfusion-independent with normal serum triglyceride levels. We suggest that severe hemolysis and chronic wasting are probably responsible for the hypertriglyceridemia seen in infants with thalassemia or PK deficiency.

First-trimester prenatal diagnosis of pyruvate kinase deficiency in an Indian family with the pyruvate kinase-Amish mutation

Pyruvate kinase (PK) deficiency is a rare red cell glycolytic enzymopathy. The purpose of the present investigation was to offer prenatal diagnosis for PK deficiency to a couple who had a previous child with severe enzyme deficiency and congenital non-spherocytic hemolytic anemia. PK deficiency was identified in the family by assaying the enzyme activity in red cells. Chorionic villus sampling was performed in an 11-week gestation and the mutation was located in exon 10 of the PKLR gene characterized by polymerase chain reaction and using restriction endonuclease digestion with the MspI enzyme, which was confirmed by DNA sequencing on the ABI 310 DNA sequencer. Both the parents were heterozygous for the 1436G-->A [479 Arg-->His] mutation in exon 10 and the proband was homozygous for this mutation. The fetus was also heterozygous for this mutation and the pregnancy was continued. Prenatal diagnosis allowed the parents with a severely affected child with PK deficiency to have the reproductive choice of having the fetus tested in a subsequent pregnancy.

Red cell pyruvate kinase deficiency in neonatal jaundice cases in India.

OBJECTIVE: Pyruvate Kinase (PK) deficiency is the most common enzymopathy of the glycolytic pathway in erythrocytes. It constitutes one of the common causes of hereditary non-spherocytic hemolytic anemia. The aim of this study was to screen newborns in India for pyruvate kinase (PK) deficiency in relation to unconjugated hyperbilirubinemia. METHODS: Laboratory investigations done included complete blood counts, reticulocyte counts, direct and indirect bilirubin, assay of G6PD and PK activity, ATP and 2,3 DPG levels. All variables were studied in 50-cord blood samples from normal deliveries and 218 neonates with hyperbilirubinemia. RESULTS: 7 of the 218 cases of neonatal jaundice were PK deficient with 30-40% reduction in PK activity. These cases also had a 3-4-fold increase in 2,3 DPG:ATP ratios, which is one of the additional indicators for PK deficiency. Six of the 7 infants had a severe clinical course. CONCLUSION: This study shows that the prevalence of PK deficiency in Indian neonatal jaundice cases is 3.21%, which is relatively high. This emphasizes the need for screening neonatal hyperbilirubinemia cases in India for PK deficiency.

Anemia hemolítica no esferocítica (AHCNE) por deficiencia de piruvato quinasa: informe del segundo caso en Costa Rica / Nonspherocytic hemolytic anemia to piruvate kinase deficiency: Inform of second case in Costa Rica

Se describe el segundo caso hallado en Costa Rica de anemia hemolítica crónica no esferocítica (AHCNE) por deficiencia de un piruvato quinasa, en una niña de 12 años de edad. Del estudio familiar, inicialmente orientado en su diagnóstico por una prueba positiva del cianuro ascorbato, se sugiere el posible caracter doble heterocigoto de la deficiencia en la paciente, eventualmente dada por dos variables enzimáticas por cooperación negativa

Erythrocyte glucose-6-phosphate dehydrogenase and pyruvate kinase activities in hemoglobin H disease.

Erythrocyte glucose-6-phosphate dehydrogenase (G6PD) and pyruvate kinase (PK) activities were studied in hemoglobin H (HbH) patients by spectrophotometric method, cytochemical method and the methemoglobin reduction (MR) test for the detection of heterozygous G6PD deficiency. G6PD deficiency was found in 7 of 64 cases (10.9%), including 3 cases of genotype alpha 1/alpha 2 and 4 cases of genotype alpha 1/CS. None of the HbH patients was found to be PK-deficient. Spectrophotometrically determined G6PD and PK activities were significantly higher in HbH patients than in normals (p less than 0.001), whereas the MR test yielded a significantly lower percentage of residual methemoglobin in HbH patients than in normals (p less than 0.05). All three methods were efficient in the detection of hemizygous G6PD deficiency in HbH patients, but not in G6PD-deficient females.

A case of pre-leukaemia masquerading as haemolytic anaemia due to multi-enzymopathy of the red cell.

A 19 year old woman presented as a case of haemolytic anaemia due to multi-enzyme deficiency of the erythrocyte. After a transient improvement with folic acid therapy, she developed acute myeloblastic leukaemia. This is the second reported case of a myelodysplastic syndrome presenting with a haemolytic picture and subsequently developing an acute myeloblastic leukaemia.