Hassan M. Yaish

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.Am. J. Hematol. 90:825–830, 2015.

A study of prospective surveillance for inhibitors among persons with haemophilia in the united states

Inhibitors are a rare but serious complication of treatment of patients with haemophilia. Phase III clinical trials enrol too few patients to adequately assess new product inhibitor risk. This project explores the feasibility of using a public health surveillance system to conduct national surveillance for inhibitors. Staff at 17 U.S. haemophilia treatment centres (HTC) enrolled patients with haemophilia A and B into this prospective study. HTC staff provided detailed historic data on product use and inhibitors at baseline, and postenrolment patients provided monthly detailed infusion logs. A central laboratory performed inhibitor tests on blood specimens that were collected at baseline, annually, prior to any planned product switch or when clinically indicated. The central laboratory also performed genotyping of all enrolled patients. From January 2006 through June 2012, 1163 patients were enrolled and followed up for 3329 person‐years. A total of 3048 inhibitor tests were performed and 23 new factor VIII inhibitors were identified, 61% of which were not clinically apparent. Infusion logs were submitted for 113 205 exposure days. Genotyping revealed 431 distinct mutations causing haemophilia, 151 of which had not previously been reported elsewhere in the world. This study provided critical information about the practical issues that must be addressed to successfully implement national inhibitor surveillance. Centralized testing with routine monitoring and confirmation of locally identified inhibitors will provide valid and representative data with which to evaluate inhibitor incidence and prevalence, monitor trends in occurrence rates and identify potential inhibitor outbreaks associated with products.

Six children with pyruvate kinase deficiency from one small town: Molecular characterization of the PK-LR gene

We identified the pyruvate kinase liver/red cell enzyme gene mutation of 8 children previously diagnosed with pyruvate kinase deficiency who were living in a remote town in the western United States. Six were found to be homozygous for the mutation 1529G-A (510 Arg-Gln). Two previously thought to have pyruvate kinase deficiency did not, because they were heterozygous.

Clinical utility of next‐generation sequencing in the diagnosis of hereditary haemolytic anaemias

Hereditary haemolytic anaemias are genetically and phenotypically heterogeneous disorders characterized by increased red cell destruction, with consequences ranging from innocuous to severe life‐threatening anaemia. Diagnostic laboratories endeavour to assist clinicians reach the exact patient diagnosis by using tests principally based on morphological and biochemical techniques. However, these routine studies may be inconclusive, particularly in newborn infants and when transfusions have recently been administered. Large numbers and size of the potentially involved genes also impose a practical challenge for molecular diagnosis using routine sequencing approaches. To overcome these diagnostic shortcomings, we have utilized next‐generation sequencing to provide a high‐throughput, highly sensitive assay. We developed a panel interrogating 28 genes encoding cytoskeletal proteins and enzymes with sequencing coverage of the coding regions, splice site junctions, deep intronic and regulatory regions. We then evaluated 19 samples, including infants with unexplained extreme hyperbilirubinaemia and patients with transfusion‐dependent haemolytic anaemia. Where possible, inheritance patterns of pathogenic mutations were determined by sequencing of immediate relatives. We conclude that this next‐generation sequencing panel could be a cost‐effective approach to molecular diagnosis of hereditary haemolytic anaemia, especially when the family history is uninformative or when routine laboratory testing fails to identify the causative haemolytic process.

Hemolytic Disorders Causing Severe Neonatal Hyperbilirubinemia

A shortened erythrocyte life span, because of hemolytic disorders, is a common cause of extreme neonatal hyperbilirubinemia. Clinical and laboratory examinations can frequently identify the underlying cause of extreme neonatal hyperbilirubinemia. In this article, several tests, techniques, and approaches have been reviewed, including red blood cell morphology assessment, end-tidal carbon monoxide quantification, eosin-5-maleimide flow cytometry, as well as next-generation DNA sequencing using neonatal jaundice panels.

A Pediatrician’s Practical Guide to Diagnosing and Treating Hereditary Spherocytosis in Neonates

Newborn infants who have hereditary spherocytosis (HS) can develop anemia and hyperbilirubinemia. Bilirubin-induced neurologic dysfunction is less likely in these neonates if the diagnosis of HS is recognized and appropriate treatment provided. Among neonates listed in the USA Kernicterus Registry, HS was the third most common underlying hemolytic condition after glucose-6-phosphate dehydrogenase deficiency and ABO hemolytic disease. HS is the leading cause of direct antiglobulin test (direct Coombs) negative hemolytic anemia requiring erythrocyte transfusion in the first months of life. We anticipate that as physicians become more familiar with diagnosing HS in the newborn period, fewer neonates with HS will develop hazardous hyperbilirubinemia or present to emergency departments with unanticipated symptomatic anemia. We predict that early suspicion, prompt diagnosis and treatment, and anticipatory guidance will prevent adverse outcomes in neonates with HS. The purpose of this article was to review the neonatal presentation of HS and to provide practical and up-to-date means of diagnosing and treating HS in neonates.

Variations in both α-spectrin (SPTA1) and β-spectrin ( SPTB ) in a neonate with prolonged jaundice in a family where nine individuals had hereditary elliptocytosis.

We cared for a neonate who had problematic hyperbilirubinemia born into a family where nine first-degree relatives had hereditary elliptocytosis (HE). As neonates, the nine relatives did not have any significant jaundice or anemia that was recognizable. Blood films on the proband suggested a diagnosis of pyropoikilocytosis. Analysis of the α-spectrin gene (SPTA1) in the proband revealed two previously reported low-frequency heterozygous polymorphisms of unknown clinical significance and the αLELY allele. In addition, a novel heterozygous mutation was identified in exon 2 of the β-spectrin gene SPTB. No mutations were identified in ANK1 (ankyrin-1), SLC4A1 (band 3), EPB41 (band 4.1), or EPB42 (band 4.2).

Neonatal Death Suspected To Be From Sepsis Was Found To Be Kernicterus With G6PD Deficiency

We cared for a term male infant born to Burmese immigrants. At about 24 hours a total serum bilirubin (TSB) was 9.3 mg/dL, and phototherapy was begun. It was stopped 48 hours later, with a TSB of 10.9 mg/dL, and he was discharged from the hospital with an appointment for a repeat TSB check 48 hours later. A few hours before the appointment he became listless and apneic, and his parents took him to the emergency department of the regional children’s hospital, where sepsis was suspected. The TSB was 41 mg/dL. He died 4 hours later, despite intensive care efforts, with opisthotonus and refractory hypotension. Blood drawn before the exchange transfusion had low glucose-6-phosphate dehydrogenase (G6PD) enzymatic activity, and sequencing of the G6PD gene revealed the G6PD Mahidol mutation (c.487G>A). Cultures and postmortem examination did not demonstrate an infectious process, but kernicterus was present. Acute kernicterus can mimic septic shock.

Thrombocytopenia in late preterm and term neonates after perinatal asphyxia

A recent NHLBI conference concluded that platelet (PLT) transfusions of neonates must become more evidence based. One neonatal disorder for which transfusions are given is a poorly defined entity, the “thrombocytopenia of perinatal asphyxia.” To expand the evidence base for this entity, we performed a multicentered, retrospective analysis of neonates with perinatal asphyxia.

CD56-negative extranodal nasal type NK/T-cell lymphoma

Extranodal natural killer (NK)/T‐cell lymphoma, nasal type, is a rare lymphoma that occurs predominantly in Asian adults. In this report, we describe the clinical and pathologic features of an unusual aggressive lymphoid neoplasm in a child and review the literature on NK/T‐cell lymphoma in children. The patient was a 4‐year‐old Native American male with facial swelling, lymphadenopathy, and fevers. Biopsy demonstrated neoplastic lymphoid cells that expressed CD3, CD8, TIA‐1, and EBV‐encoded RNA without CD56. The patient failed multiagent chemotherapy and died of therapy‐related complications. This case represents an extranodal NK/T‐cell lymphoma, nasal type, with an unusual lack of CD56. Pediatr Blood Cancer 2010;55:186–189.