Successful Liver Transplantation for Adolescent Patient With Pyruvate Kinase Deficiency-induced Cirrhosis.

We present the case of a successful liver transplant in a young adult patient with cholestasis and cirrhosis secondary to severe pyruvate kinase (PK) deficiency. Liver transplant resulted in resolution of liver dysfunction, decreased need for blood transfusions and eligibility for bone marrow transplantation. This case represents the third reported patient in the literature with severe PK deficiency who successfully underwent liver transplant as a result of profound cholestasis and liver failure. Explant pathology demonstrated a lack of significant iron deposition indicating that PK deficiency predisposes the liver to injury independent of transfusion-related iron overload.

Hereditary spherocytosis is associated with decreased pyruvate kinase activity due to impaired structural integrity of the red blood cell membrane.

Hereditary spherocytosis (HS) is characterised by increased osmotic fragility and enhanced membrane loss of red blood cells (RBC) due to defective membrane protein complexes. In our diagnostic laboratory, we observed that pyruvate kinase (PK) activity in HS was merely slightly elevated with respect to the amount of reticulocytosis. In order to evaluate whether impaired PK activity is a feature of HS, we retrospectively analysed laboratory data sets from 172 unrelated patients with HS, hereditary elliptocytosis (HE), glucose-6-phosphate dehydrogenase (G6PD) or PK deficiency, sickle cell or haemoglobin C disease, or ß-thalassaemia minor. Results from linear regression analysis provided proof that PK activity decreases with rising reticulocyte counts in HS (R2  = 0·15; slope = 9·09) and, less significantly, in HE (R2  = 0·021; slope = 8·92) when compared with other haemolytic disorders (R2  ≥ 0·65; slopes ≥ 78·6). Reticulocyte-adjusted erythrocyte PK activity levels were significantly lower in HS and even declined with increasing reticulocytes (R2  = 0·48; slope = -9·74). In this report, we describe a novel association between HS and decreased PK activity that is apparently caused by loss of membrane-bound PK due to impaired structural integrity of the RBC membrane and may aggravate severity of haemolysis in HS.

Appraisal of patient-reported outcome measures in analogous diseases and recommendations for use in phase II and III clinical trials of pyruvate kinase deficiency.

PURPOSE: Pyruvate kinase deficiency (PKD) is a rare disease and understanding of its epidemiology and associated burden remains limited. With no current curative therapy, clinical manifestations can be life threatening, clinically managed by maintaining adequate hemoglobin levels through transfusion and subsequent support, but with frequent complications. Treatment goals are to maintain/improve the patient's quality of life. With new therapies, reliable, valid, and relevant patient-reported outcome (PRO) tools are required for use in clinical trials. METHODS: Systematic literature search identified no current PRO tools for capturing/measuring the impact of PKD and treatments in clinical trials. Therefore, the search strategy was revised to consider conditions analogous to PKD in terms of symptoms and impacts that might serve as parallels to the experience in PKD; this included sickle cell anemia, thalassemia, and hemolytic anemia. Psychometric properties, strengths, and weakness of selected appropriate PRO instruments were compared, and recommendations made for choice of PRO tools. RESULTS: In adult populations, EORTC QLQ C30 and SF-36v2 are recommended, the former being a basic minimum, covering generic HRQoL, and core symptoms such as fatigue. In pediatric populations, PedsQL Generic Core Scale to measure HRQoL and PedsQL MFS scale to measure fatigue are recommended. CONCLUSIONS: Some symptoms/life impacts may be unique to PKD and not observable in analogous conditions. A 'Physico-Psychosocial Model' derived from the 'Medical Model' is proposed to form the basis for a hypothesized conceptual framework to address the development of PKD-specific PRO instruments.

Screening of hereditary spherocytosis and pyruvate kinase deficiency by automated blood count using erythrocytic and reticulocytic parameters.

INTRODUCTION: Development of additional parameters for complete blood count has emerged in recent hematology analyzers, leading to many publications. However, few studies have been conducted on advanced RBC parameters and hemolytic anemias. We investigated the interest of Sysmex unique parameters, MicroR and HypoHe, as well as the immature fraction of reticulocytes (IRF) in combination with complete blood and reticulocyte count, for screening hereditary spherocytosis (HS) and pyruvate kinase deficiency. METHODS: We analyzed 182 samples using Sysmex XE-5000 analyzers from a cohort of red cell disorder patients from the Rouen University Hospital. These included 47 HS, 17 pyruvate kinase deficiencies, sickle cell diseases and trait, ß-thalassemia minor, iron deficiencies, and 489 samples from a routine group. RESULTS: Combining five parameters (hemoglobin level, reticulocyte count, IRF, MicroR, and %HypoHe), we developed a specific screening tool for HS allowing a sensitivity of 100% and a specificity of 92.1% and a specific screening tool for pyruvate kinase deficiencies allowing a sensitivity of 100% and a specificity of 96.5%. These parameters were also found accurate in infants and in HS without anemia. CONCLUSION: We propose a costless, easy-to-use, and efficient approach to detect HS and pyruvate kinase deficiencies using Sysmex analyzers. These screening tools may help diagnosis of these disorders, help prevent complications, and result in a better management of these patients.

Residual pyruvate kinase activity in PKLR-deficient erythroid precursors of a patient suffering from severe haemolytic anaemia.

OBJECTIVE: Here, we present a 7-year-old patient suffering from severe haemolytic anaemia. The most common cause of chronic hereditary non-spherocytic haemolytic anaemia is red blood cell pyruvate kinase (PK-R) deficiency. Because red blood cells rely solely on glycolysis to generate ATP, PK-R deficiency can severely impact energy supply and cause reduction in red blood cell lifespan. We determined the underlying cause of the anaemia and investigated how erythroid precursors in the patient survive. METHODS: PK activity assays, Western blot and Sanger sequencing were employed to determine the underlying cause of the anaemia. Patient erythroblasts were cultured and reticulocytes were isolated to determine PK-R and PKM2 contribution to glycolytic activity during erythrocyte development. RESULTS: We found a novel homozygous mutation (c.583G>A) in the PK-R coding gene (PKLR). Although this mutation did not influence PKLR mRNA production, no PK-R protein could be detected in the red blood cells nor in its precursors. In spite of the absence of PK-R, the reticulocytes of the patient exhibited 20% PK activity compared with control. Western blotting revealed that patient erythroid precursors, like controls, express residual PKM2. CONCLUSIONS: We conclude that PKM2 rescues glycolysis in PK-R-deficient erythroid precursors.

Red blood cell PK deficiency: An update of PK-LR gene mutation database.

Pyruvate kinase (PK) deficiency is known as being the most common cause of chronic nonspherocytic hemolytic anemia (CNSHA). Clinical PK deficiency is transmitted as an autosomal recessive trait, that can segregate neither in homozygous or in a compound heterozygous modality, respectively. Two PK genes are present in mammals: the pyruvate kinase liver and red blood cells (PK-LR) and the pyruvate kinase muscle (PK-M), of which only the first encodes for the isoenzymes normally expressed in the red blood cells (R-type) and in the liver (L-type). Several reports have been published describing a large variety of genetic defects in PK-LR gene associated to CNSHA. Herein, we present a review of about 250 published mutations and six polymorphisms in PK-LR gene with the corresponding clinical and molecular data. We consulted the PubMed website for searching mutations and papers, along with two main databases: the Leiden Open Variation Database (LOVD, https://grenada.lumc.nl/LOVD2/mendelian_genes/home.php?select_db=PKLR) and Human Gene Mutation Database (HGMD, http://www.hgmd.cf.ac.uk/ac/gene.php?gene=PKLR) for selecting, reviewing and listing the annotated PK-LR gene mutations present in literature. This paper is aimed to provide useful information to clinicians and laboratory professionals regarding overall reported PK-LR gene mutations, also giving the opportunity to harmonize data regarding PK-deficient individuals.

Erythrocyte pyruvate kinase deficiency: 2015 status report.

Over the last several decades, our understanding of the genetic variation, pathophysiology, and complications of the hemolytic anemia associated with red cell pyruvate kinase deficiency (PKD) has expanded. Nonetheless, there remain significant gaps in our knowledge with regard to clinical care and monitoring. Treatment remains supportive with phototherapy and/or exchange transfusion in the newborn period, regular or intermittent red cell transfusions in children and adults, and splenectomy to decrease transfusion requirements and/or anemia related symptoms. In this article, we review the clinical diversity of PKD, the current standard of treatment and for supportive care, the complications observed, and future treatment directions.

Partial pyruvate kinase deficiency aggravates the phenotypic expression of band 3 deficiency in a family with hereditary spherocytosis.

In a family with mild dominant spherocytosis, affected members showed partial band 3 deficiency. The index patient showed more severe clinical symptoms than his relatives, and his red blood cells displayed concomitant low pyruvate kinase activity. We investigated the contribution of partial PK deficiency to the phenotypic expression of mutant band 3 in this family. Pyruvate kinase deficiency and band 3 deficiency were characterized by DNA analysis. Results of red cell osmotic fragility testing, the results of cell deformability obtained by the Automated Rheoscope and Cell Analyzer and the results obtained by Osmotic Gradient Ektacytometry, which is a combination of these tests, were related to the red cell ATP content. Spherocytosis in this family was due to a novel heterozygous mutation in SLC4A1, the gene for band 3. Reduced PK activity of the index patient was attributed to a novel mutation in PKLR inherited from his mother, who was without clinical symptoms. Partial PK deficiency was associated with decreased red cell ATP content and markedly increased osmotic fragility. This suggests an aggravating effect of low ATP levels on the phenotypic expression of band 3 deficiency.

Dyserythropoiesis in a child with pyruvate kinase deficiency and coexistent unilateral multicystic dysplastic kidney.

Pyruvate kinase (PK) deficiency is the commonest enzyme deficiency in the glycolytic pathway leading to hemolytic anemia secondary to decreased Adenosine Triphosphate (ATP) synthesis in the red cells. synthesis. PK deficiency due to mutations in the PKLR (1q21) gene leads to highly variable clinical presentation ranging from severe fetal anemia to well compensated anemia in adults. We describe dyserythropoiesis in the bone marrow of a child with transfusion dependent anemia and unilateral multicystic dysplastic kidney (MCDK) mimicking Congenital Dyserythropoietic Anemia type I (CDA type I). Persistently low erythrocyte PK levels and double heterozygous mutations present in the PKLR gene confirmed the diagnosis of PK deficiency.