The Pyruvate Kinase Deficiency Global Longitudinal (Peak) Registry: rationale and study design

INTRODUCTION

Pyruvate kinase (PK) deficiency is a rare, under-recognised, hereditary condition that leads to chronic haemolytic anaemia and potentially serious secondary complications, such as iron overload, cholecystitis, pulmonary hypertension and extramedullary haematopoiesis. It is an autosomal recessive disease caused by homozygous or compound heterozygous mutations in the PKLR gene. Due to its rarity and clinical heterogeneity, information on the natural history and long-term clinical course of PK deficiency is limited, presenting major challenges to patient management, the development of new therapies and establishing disease-specific treatment recommendations. The Pyruvate Kinase Deficiency Global Longitudinal (Peak) Registry is an initiative to address the gaps in the knowledge of PK deficiency. This manuscript describes the objectives, study design and methodology for the Peak Registry.

METHODS AND ANALYSIS

The Peak Registry is an observational, longitudinal, global registry of adult and paediatric patients with a genetically confirmed diagnosis of PK deficiency. The Peak Steering Committee is composed of 11 clinicians and researchers with experience in the diagnosis and management of PK deficiency from 10 countries, a patient representative and representatives from the sponsor (Agios Pharmaceuticals). The registry objective is to foster an understanding of the longitudinal clinical implications of PK deficiency, including its natural history, treatments and outcomes, and variability in clinical care. The aim is to enrol up to 500 participants from approximately 60 study centres across 20 countries over 7 years, with between 2 and 9 years of follow-up. Data will include demographics, diagnosis history, genotyping, transfusion history, relevant clinical events, medications, emergency room visits and hospitalisations.

ETHICS AND DISSEMINATION

Registry protocol and informed consent forms are approved by institutional review boards/independent ethics committees at each study site. The study is being conducted in accordance with the Declaration of Helsinki. Registry data will be published in peer-reviewed journal articles and conference publications.

TRIAL REGISTRATION NUMBER

NCT03481738.

Haemoglobin Bristol-Alesha in a child with non-spherocytic severe haemolytic anaemia and marked anisochromic poikilocytosis with basophilic stippling and amorphous intracellular content

Here we describe a retrospective study of a 10-year-old girl, adopted from India, and referred to the Rare Anemias Unit for the diagnosis of a severe haemolytic anaemia of unknown etiology. Blood film examination revealed markedly abnormal red cell morphology characterised by a mixture of very pale (hypochromic) cells with basophilic stippling and macrocytic cells containing coarse basophilic dots and an amorphous material of unknown origin. With a presumptive diagnosis of pyruvate kinase deficiency (PK), the patient had been splenectomised at 7 years of age with a partial recovery of the anaemia and a decrease of the blood transfusion rate. Three years after splenectomy, the patient was revisited and a haemoglobin stability test was performed with a positive result. Accordingly, the correct diagnosis was an unstable haemoglobinopathy. Targeted next generation sequencing (t-NGS) revealed haemoglobin Bristol-Alesha, a hyper unstable haemoglobinopathy associated with severe haemolytic anaemia. Since unstable haemoglobins do not necessarily have specific red cell morphological abnormalities, our findings reinforce the need to include, the haemoglobin stability test, in the first diagnostic approach of hemolytic anaemias of unknown etiology.

Rare Anaemias, Sickle-Cell Disease and COVID-19

For rare haematological diseases (RHD), the first question to be answered is if patients with benign red blood cell (RBC) defects like haemoglobinopathies, membranopathies and enzymopathies are more vulnerable to COVID-19 infection. Up to now, there is no yet literature on the subject, but, like in general population, the presence of comorbidities such as diabetes, heart disease, pulmonary hypertension, reduced kidney and/or liver function, worsen the effects of the infection. Splenectomy may be an additional risk factor. (www.actabiomedica.it)

Red Blood Cell Membrane Conductance in Hereditary Haemolytic Anaemias

Congenital haemolytic anaemias are inherited disorders caused by red blood cell membrane and cytoskeletal protein defects, deviant hemoglobin synthesis and metabolic enzyme deficiencies. In many cases, although the causing mutation might be known, the pathophysiology and the connection between the particular mutation and the symptoms of the disease are not completely understood. Thus effective treatment is lagging behind. As in many cases abnormal red blood cell cation content and cation leaks go along with the disease, by direct electrophysiological measurements of the general conductance of red blood cells, we aimed to assess if changes in the membrane conductance could be a possible cause. We recorded whole-cell currents from 29 patients with different types of congenital haemolytic anaemias: 14 with hereditary spherocytosis due to mutations in α-spectrin, β-spectrin, ankyrin and band 3 protein; 6 patients with hereditary xerocytosis due to mutations in Piezo1; 6 patients with enzymatic disorders (3 patients with glucose-6-phosphate dehydrogenase deficiency, 1 patient with pyruvate kinase deficiency, 1 patient with glutamate-cysteine ligase deficiency and 1 patient with glutathione reductase deficiency), 1 patient with β-thalassemia and 2 patients, carriers of several mutations and a complex genotype. While the patients with β-thalassemia and metabolic enzyme deficiencies showed no changes in their membrane conductance, the patients with hereditary spherocytosis and hereditary xerocytosis showed largely variable results depending on the underlying mutation.

Meeting Report: The Equality Project on Endocrine Complications in Thalassemia: Selected Highlights from the First Turkish Congress, Antalya, 10th-11th December 2018

Major difficulties reported by endocrinologists /pediatricians/ hematologists in the care of thalassemic patients with endocrine complications were: lack of facilities, correct interpretation of tests, unfamiliarity with medical treatment and the cost of diagnostics and therapeutics. Therefore, there is a felt need to educate and train more endocrinologists/pediatricians/hematologists in this field in order to optimise growth and prevent endocrine complications. To achieve this goal, in 2015, a project called Equality was submitted by three countries (Turkey, Spain and Italy) and approved by the European Union (EU) with the aim to train doctors and nurses, taking care of youth and young adults TM patients, in the prevention, diagnosis, and management of endocrine disorders. The selected highlights of the First Turkish Congress held in Antalya (10th-11th December 2018) are reported. Overall the conference provided a wide coverage of conventional treatment of thalassemias and endocrine complications in patients with β-thalassemia major. Regular surveillance, early diagnosis, treatment and follow-up in a multi-disciplinary specialized setting are recommended.

The experience of a tertiary unit on the clinical phenotype and management of hypogonadism in female adolescents and young adults with transfusion dependent thalassemia

BACKGROUND

Transfusion-dependent β-thalassemia (TDT) is associated with several complications necessitating a multidisciplinary approach for diagnosis, treatment and follow-up. Hypogonadism in female TDT patients is one of the most common endocrine complications, requiring hormone replacement therapy (HRT) throughout reproductive life. Little is known about the balance of benefits versus risks of treatment with sex steroids.

AIM

The aim of this manuscript is to review the action and the associated adverse effects of HRT in hypogonadal TDT females.

DESIGN

Retrospective medical database records from a single centre, over a period of 38 years (January 1980 to June 2018), were reviewed.

STUDY POPULATION

Forty-two cases of hypogonadism in TDT females followed in a pediatric and adolescent outpatient clinics, were in included in the study.

METHODS

Auxological, clinical, laboratory, hormonal and imaging investigations were reviewed, as well as all adverse events registered during HRT.

MAIN RESULTS

In general, HRT was safe for most patients. There were few minor side effects and a couple of rare but serious adverse events.

CONCLUSIONS

The study provides a representative clinical profile of long-term effects of HRT in hypogonadal adolescents and young adult TDT women. Our results highlight also the need for further research in other areas for which HRT may have a role.  We hope this will contribute to a wider understanding, and potential improvement, of patient safety and quality of life.

Is Increased Intracellular Calcium in Red Blood Cells a Common Component in the Molecular Mechanism Causing Anemia?

For many hereditary disorders, although the underlying genetic mutation may be known, the molecular mechanism leading to hemolytic anemia is still unclear and needs further investigation. Previous studies revealed an increased intracellular Ca²⁺ in red blood cells (RBCs) from patients with sickle cell disease, thalassemia, or Gardos channelopathy. Therefore we analyzed RBCs' Ca²⁺ content from 35 patients with different types of anemia (16 patients with hereditary spherocytosis, 11 patients with hereditary xerocytosis, 5 patients with enzymopathies, and 3 patients with hemolytic anemia of unknown cause). Intracellular Ca²⁺ in RBCs was measured by fluorescence microscopy using the fluorescent Ca²⁺ indicator Fluo-4 and subsequent single cell analysis. We found that in RBCs from patients with hereditary spherocytosis and hereditary xerocytosis the intracellular Ca²⁺ levels were significantly increased compared to healthy control samples. For enzymopathies and hemolytic anemia of unknown cause the intracellular Ca²⁺ levels in RBCs were not significantly different. These results lead us to the hypothesis that increased Ca²⁺ levels in RBCs are a shared component in the mechanism causing an accelerated clearance of RBCs from the blood stream in channelopathies such as hereditary xerocytosis and in diseases involving defects of cytoskeletal components like hereditary spherocytosis. Future drug developments should benefit from targeting Ca²⁺ entry mediating molecular players leading to better therapies for patients.

Recommendations for Centres of Expertise in Rare Anaemias. The ENERCA White Book

The Community added value of Centres of Expertise (CoE) and European Reference Networks (ERN) is particularly high for rare diseases (RD) due to the rarity of these conditions, which implies both a small number of patients and scarcity of expertise within a single country. Gathering expertise at the European level is therefore, paramount in order to ensure equal access to accurate information, appropriate and timely diagnosis and high quality clinical care and follow up for patients with rare diseases. This applies particularly to rare anaemias due to the high number of different rare diseases that constitute this group. In this context, the European Network for Rare and Congenital Anaemias (ENERCA), co-financed by the European Commission, was created in 2002 with the aim of prevention and management of rare anaemias (RA) and the development and promotion of policies to improve the well-being of European Union citizens. The ENERCA White Book is a position paper, developed as a deliverable of the ENERCA (phase 3) project that intends to contribute to the creation of a ERN in RA (ERN-RA) by preparation of the recommendations and, in particular, the definition of the criteria that CoE, local centres (LC) and their interrelations have to fulfil as healthcare providers. It has been nourished by all the activities that have been performed over the past ten years within the ENERCA framework. The White Book is addressed to authorities in charge of the identifying CoE, as an essential requirement for the official recognition of the ERN, to European and national health authorities, Healthcare centres and health professionals, as well as to all other stakeholders interested in RA. It is also addressed to the patients, as a way to empower their community in this process. One particular characteristic of the White Book is the integration of the three main aspects of a CoE: (a) ethical and legal frameworks to ensure the non-discrimination and non-stigmatisation of rare disease patients across Europe, within their sphere of competencies; (b) clinical and laboratory frameworks for defining technical and quality criteria including scope, general and disease specific elements currently defined as technical and professional standards for the diagnosis, treatment and follow-up of patients with RA; and (c) the expectations patients have of CoE. Conceived as a working tool directed to a broad range of stakeholders, the White book has been designed and structured to be comprehensible even to non-technical and /or non-professional audiences. The reader will find an up-to-date description and epidemiological information on RA as well as the European Union background policies for defining CoE and ERN-RA. A working group was created with experts of different profiles, known as the European Working Group on Rare Anaemias (EGRA). In order to achieve its objectives, the methodology used by EGRA, was characterised by three main principles: Interdisciplinary, European coverage, and evidence-based principles. Work has been developed into four sequential steps: 1. Analysis of the current situation of RA in Europe by healthcare professionals in order to identify the most relevant issues that have to be addressed by a centre in order for it to be recommended as CoE. 2. Preparation of questionnaires to perform surveys on how the relevant issues identified in step 1 can be translated into practical recommendations. 3. Analysis of the questionnaire results by face to face meetings, feedback and consensus evaluation, and 4. Preparation of a report on ENERCA policy recommendations for CoE. This report is presented in a user-friendly format, easy to understand and available through the ENERCA website (www.enerca.org). Several important conclusions can be drawn from the ENERCA White Book, including the importance of laboratories involved in the diagnosis of RA, patient oriented and multidisciplinary care at the CoE, the need for coordination and cooperation within and outside the centre, the provision of information to patients and health professionals and the involvement of public authorities at the national and European levels. Official recognition of this structure and assurance of its long term sustainability will only be achieved if public authorities work hand by hand with both professionals experts in different disciplines and patients. Finally, the ENERCA White book aims to be a practical tool for health authorities of Member States (MS) that are preparing their national directory of formally designated CoE. For this, it is important that MS authorities recognise RA as an important health component to be included within the National Plans or Actions for Rare Diseases.

Haemoglobinopathies in Europe: health & migration policy perspectives

BACKGROUND

Major haemoglobinopathies (MH), such as thalassaemia syndromes (Thal) and sickle cell disorders (SCD), are genetic defects associated with chronic anaemia and other complications. In Europe, MH are rare diseases (RD) but their prevalence is significantly growing in many countries due to mobility and migration flows. This creates a growing health problem in the EU that has not yet been effectively addressed by Member States (MS) authorities. The present study has been conducted with the aim of: (i) providing an overview of policies for MH in 10 EU member states (MS) (ii) analysing the challenges linked to these RD due to growing requirements imposed by population, mobility and migration trends and (iii) identifying gaps, proposing improvements on existing policies, or developing new ones to fit the identified needs.

METHODS

The study has been undertaken by a group of members of the European Network for Rare and Congenital Anaemias (ENERCA) and the Thalassaemia International Federation (TIF), in collaboration with the public affairs firm Burson-Marsteller Brussels. Data from 10 EU countries have been gathered using targeted desk research and one-to-one interviews with local stakeholders, including healthcare professionals, patients and public health officers/providers.

RESULTS

1. MH are the most common RD in all the 10 countries, 2. Data on prevalence, overall burden, trends, and clinical follow up costs are lacking in most countries. 3. Neonatal screening practices show a wide variation across and within countries. 4. Awareness on MH and their related complications is very low, exception made of Italy, Greece, Cyprus and UK, 5. No disaggregated data is available to understand the impact of mobility and migration on the prevalence of haemoglobinopathies, and how healthcare delivery systems should adapt to respond to this situation. 6. Targeted policy measures and/or actions are generally lacking and/or delayed.

CONCLUSIONS

Ten policy recommendations have been drawn from this study, building on 2006 WHO recommendations for MH to include haemoglobinopathies in National Plans of Actions for Rare Diseases.

Epidemiology of rare anaemias in Europe

Registry and epidemiological data of Rare Anaemias (RA) in Europe is in general still incomplete and/or partially documented. One important issue is the increasing prevalence of haemoglobin disorders (HD) due to migrations from high prevalence areas. The size of the problem, particularly for sickle cell disease (SCD), is already having an impact on health services in many European countries. The best known cause of rare anaemias associated with congenital haemolytic anaemia (CHA) in Europe is Hereditary Spherocytosis (HS) a red blood cell (RBC) membrane defect with a prevalence of 1 to 5 cases per 10.000 individuals. Some other causes of CHA are extremely rare and only few individual cases have been described worldwide (i.e. some RBC enzymopathies). Congenital defects of erythropoiesis are less frequent Diamond-Blackfan Anaemia (DBA) and Fanconi Anaemia (FA) exhibit a very low prevalence ranging from 4 to 7 per million live births. Congenital Dyserythropoietic Anaemia (CDA), a genetically heterogenous group, is still less frequent and exhibits a large variability of frequency depending on the European region: 0.1-3.0 cases per million births In addition many cases are known from a large autosomal dominant family in Sweden. Although incidence of Paroxysmal Nocturnal Haemoglobinuria (PNH) in Europe is still unknown, data collection from different sources has given quotes of 1 case per 100,000 individuals to 5 cases per million births.

Glucose phosphate isomerase deficiency: enzymatic and familial characterization of Arg346His mutation

Homozygous glucose phosphate isomerase (GPI) deficiency is one of the most important genetic disorders responsible for chronic non-spherocytic hemolytic anemia (CNSHA), a red blood cell autosomal recessive genetic disorder which causes severe metabolic alterations. In this work, we studied a patient with CNSHA due to an 82% loss of GPI activity resulting from the homozygous missense replacement in cDNA position 1040G>A, which leads to substitution of the protein residue A346H mutation. The enzyme is present in a dimeric form necessary for normal activity; the A346H mutation causes a loss of GPI capability to dimerize, which renders the enzyme more susceptible to thermolability and produces significant changes in erythrocyte metabolism.

Phosphoglycerate mutase BB isoenzyme deficiency in a patient with non-spherocytic anemia: familial and metabolic studies

We previously reported the first case of red blood cell phosphoglycerate mutase (PGAM) isozyme BB deficiency due to the homozygous point mutation cDNA 690G->A, which causes a substitution of methionine 230 by isoleucine. In the present work we analyzed the changes in glycolytic intermediates caused by this mutation. With the exception of hexose phosphates, all other intermediates were decreased. In contrast, lactate levels were increased. The methionine 230 isoleucine change did not alter the mutated PGAM levels.

Red cell adenylate kinase deficiency: molecular study of 3 new mutations (118G>A, 190G>A, and GAC deletion) associated with hereditary nonspherocytic hemolytic anemia

We report here 2 patients with chronic nonspherocytic hemolytic anemia (CNSHA) and severe red blood cell (RBC) adenylate kinase (AK) deficiency. One of these patients, a boy of Spanish origin, exhibited a neonatal icterus and splenomegaly and required blood transfusions until the age of 2 years. The other patient was a white, American infant born to parents who were first cousins; he also presented with neonatal icterus and anemia. In neither case was psychomotor impairment observed. The first patient was found to be a compound heterozygote for 2 different missense mutations, 118G>A(Gly40Arg) and 190G>A(Gly64Arg) (cDNA sequence first described by Matsuura et al, 1989). The second patient was homozygous for an in-frame deletion (GAC) from nucleotide (nt) 498 to 500 or nt 501 to 503 of the cDNA sequence, predicting deletion of either aspartic acid (Asp) 140 or 141. The crystal structure of porcine cytosolic AK was used as a molecular model to investigate how these mutations may affect enzyme structure and function.