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Assaying Protein Kinase Activity with Radiolabeled ATP
Published on: May 26, 2017
A Case With Pyruvate Kinase Deficiency Remarkably Sensitive to Heat
Tekin Aksu1, Neşe Yarali1, Elisa Fermo2
1Department of Pediatric Hematology and Oncology, University of Health Sciences, Ankara Child Health and Diseases Hematology Oncology Training and Research Hospital, Ankara, Turkey.
Insights
Pyruvate kinase deficiency, a common cause of hemolytic anemia, was identified in a patient with a novel gene mutation. This finding highlights the genetic basis of this condition and informs potential treatments.
Area of Science:
- Biochemistry
- Genetics
- Hematology
Background:
- Pyruvate kinase (PK) deficiency is the most frequent inherited defect in the glycolytic pathway.
- It is a primary cause of congenital hemolytic anemia, characterized by red blood cell destruction.
Observation:
- An 18-year-old male presented with chronic nonspherocytic hemolytic anemia and significant heat sensitivity.
- Clinical worsening prompted exclusion of immunologic and infectious causes.
- Enzyme assays indicated reduced PK activity, suggesting PK deficiency.
Findings:
- Molecular analysis identified a novel homozygous missense mutation (c.581G>C, p.Arg194Pro) in the PK-LR gene.
- The identified mutation resulted in a heat-labile mutant enzyme.
- A heterozygous state for the bilirubin uridine diphosphate (UDP)-glucuronosyltransferase 1A1 gene ([TA]6/[TA]7) was also noted.
Implications:
- This case elucidates a novel genetic mutation contributing to pyruvate kinase deficiency.
- Understanding the molecular basis of PK deficiency aids in accurate diagnosis and management.
- Splenectomy was performed following the definitive diagnosis.
Abstract:
Pyruvate kinase (PK) deficiency is the most common defect of the glycolytic pathway leading to congenital hemolytic anemia. We present the case of an 18-year-old boy with chronic nonspherocytic hemolytic anemia, who had remarkable sensitivity to heat. Moreover, the patient showed clinical impairment in the last year. For this reason, we excluded the immunologic or infectious nature (malaria, babesia), which may play a role in the worsening of anemia. Red blood cell enzyme assay showed the presence of a significant increase in other enzyme activities, except for PK, suggesting a PK deficiency in the patient. The molecular analysis of the PK-LR gene revealed the presence of a novel homozygote missense mutation (c.581G>C, p.Arg194Pro). The mutant enzyme displayed heat instability. In addition, we analyzed bilirubin uridine diphosphate (UDP)-glucuronosyltransferase 1A1 gene that revealed a heterozygous state ([TA]6/[TA]7). After a clear diagnosis of PK deficiency, the patient underwent splenectomy.
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