Roberto H. Nussenzveig

Hematopoiesis is not clonal in healthy elderly women.

Clonality assays, based on X-chromosome inactivation, discriminate active from inactive alleles. Skewing of X-chromosome allelic usage, based on preferential methylation of one of the HUMARA alleles, was reported as evidence of clonal hematopoiesis in approximately 30% of elderly women. Using a quantitative, transcriptionally based clonality assay, we reported X-chromosome-transcribed allelic ratio in blood cells of healthy women consistent with random X-inactivation of 8 embryonic hematopoietic stem cells. Furthermore, we did not detect clonal hematopoiesis in more than 200 healthy nonelderly women. In view of the susceptibility of aging hematopoietic stem cells to epigenetic dysregulation, we reinvestigated the issue of clonality in elderly women. Forty healthy women (ages 65-92 years; mean, 81.3 years) were tested by a novel, quantitative polymerase chain reaction (qPCR) transcriptional clonality assay. We did not detect clonal hematopoiesis in any of the tested subjects. We also tested DNA from the same granulocyte samples using the methylation-based HUMARA assay, and confirmed previous reports of approximately 30% extensively skewed or monoallelic methylation, in agreement with likely age-related deregulated methylation of the HUMARA gene locus. We conclude that the transcriptionally based X-chromosome clonality assays are suitable for evaluation of clonal hematopoiesis in elderly women.

Causes of hemolysis in neonates with extreme hyperbilirubinemia

Objective:We instituted a quality improvement process to enhance our capacity to diagnose genetic hemolytic conditions in neonates with extreme hyperbilirubinemia.Study design:During a 1-year period, whenever the total serum bilirubin (TSB) was >25u2009mgu2009dl−1 a special evaluation was perfomed. If we deemed an erythrocyte membrane defect likely, based on red blood cell morphology, EMA-flow cytometry was performed. Otherwise ‘next-generation’ sequencing was performed using a panel of genes involved in neonatal hyperbilirubinemia.Result:Ten neonates had a TSB ⩾25u2009mgu2009dl−1. Two others were evaluated as part of this process at the request of their attending neonatologists, because each had a TSB >14u2009mgu2009dl−1 in the first hours after birth and required phototherapy for ⩾1 week. Explanations for the jaundice were found in all 12 neonates. Five had hereditary spherocytosis, three of which also had ABO hemolytic disease. Two had pyruvate kinase deficiency. One had severe G6PD deficiency. The other four had ABO hemolytic disease.Conclusion:On the basis of the present small case series, we suggest that among neonates with extreme hyperbilirubinemia, it can be productive to pursue a genetic basis for hemolytic disease.

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).

Detection of JAK2 mutations in paraffin marrow biopsies by high resolution melting analysis: identification of L611S alone and in cis with V617F in polycythemia vera.

Abstract JAK2 mutations provide an objective major criterion for diagnosis of myeloproliferative neoplasms in the 2008 World Health Organization classification, and are particularly useful for cases of polycythemia vera (PV). High resolution melting analysis (HRM) using DNA from fresh samples for mutation detection in JAK2 exons 12 and 14 has been reported. Here, we describe two new HRM techniques that use both fresh and formalin-fixed paraffin-embedded marrow samples, allowing for both prospective and retrospective analyses. We used these novel assays to screen DNA isolated from paraffin-embedded marrow biopsies from 104 patients with PV for mutations. HRM mutation-positive samples were subsequently sequenced. Ninety-seven samples (93.3%) were positive solely for the JAK2 p.V617F. One harbored a 33 bp duplication in exon 12 along with an exon 14 p.V617F mutation, another had an exon 12 p.H538_K539delinsL, and a third carried a previously unreported mutation in PV, p.L611S, alone, and in cis with p.V617F. This indicates that these assays can detect known and novel JAK2 mutations in exons 12 and 14 using either fresh or paraffin-embedded archival materials.

Evaluating eosin-5-maleimide binding as a diagnostic test for hereditary spherocytosis in newborn infants

Objective:Neonates with undiagnosed hereditary spherocytosis (HS) are at risk for developing hazardous hyperbilirubinemia and anemia. Making an early diagnosis of HS in a neonate can prompt anticipatory guidance to prevent these adverse outcomes. A recent comparison study showed that a relatively new diagnostic test for HS, eosin-5-maleimide (EMA)-flow cytometry, performs better than other available tests in confirming HS. However, reports have not specifically examined the performance of this test among neonates.Study design:We compared EMA-flow cytometry from blood samples of healthy control neonates vs samples from neonates suspected of having HS on the basis of severe Coombs-negative jaundice and spherocytes on blood film. The diagnosis of HS was later either confirmed or excluded based on clinical findings and next generation sequencing (NGS) after which we correlated the EMA-flow results with the diagnosis.Result:EMA-flow was performed on the blood of 31 neonates; 20 healthy term newborns and 11 who were suspected of having HS. Eight of the 11 were later confirmed positive for HS and one was confirmed positive for hereditary elliptocytosis (HE). All nine had persistently abnormal erythroid morphology, reticulocytosis and anemia, and eight of the nine had relevant mutations discovered using NGS. The other was confirmed positive for HS on the basis that a parent had HS, and the neonate’s spherocytosis, reticulocytosis and anemia persisted. The 20 healthy controls and the 2 in whom HS was initially suspected but later excluded all had EMA-flow results in the range reported in healthy children and adults. In contrast, all nine in whom HS or HE was confirmed had abnormal EMA-flow results consistent with previous reports in older children and adults with HS.Conclusion:Although our sample size is small, our findings are consistent with the literature in older children and adults suggesting that EMA-flow cytometric testing performs well in supporting the diagnosis of HS/HE during the early neonatal period.

Characterization of metastatic urothelial carcinoma via comprehensive genomic profiling of circulating tumor DNA

Biomarker‐guided clinical trials are increasingly common in metastatic urothelial carcinoma (mUC), yet patients for whom contemporary tumor tissue is not available are not eligible. Technological advancements in sequencing have made cell‐free circulating DNA (cfDNA) next‐generation sequencing (NGS) readily available in the clinic. The objective of the current study was to determine whether the genomic profile of mUC detected by NGS of cfDNA is similar to historical tumor tissue NGS studies. A secondary objective was to determine whether the frequency of genomic alterations (GAs) differed between lower tract mUC (mLTUC) and upper tract mUC (mUTUC).

Novel α-Spectrin Mutation in Trans with α-SpectrinLEPRA Causing Severe Neonatal Jaundice from Hereditary Spherocytosis

We evaluated a neonate with severe jaundice but a negative family history. Spherocytes were present and suspected hereditary spherocytosis was confirmed by osmotic fragility and eosin-5-maleimide erythrocyte staining. We found he was a compound heterozygote for two pathogenic mutations in the gene encoding α-spectrin: a previously reported αLEPRA inherited from his asymptomatic mother, and a novel α-spectrin mutation in intron 45 +1 disrupting the consensus splice site, from his asymptomatic father.

A previously unknown mutation in the pyruvate kinase gene (PKLR) identified from a neonate with severe jaundice.

We report a neonate with early and severe hemolytic jaundice and low erythrocyte pyruvate kinase enzymatic activity (<2 U/g hemoglobin, reference interval 9-22). We found her asymptomatic mother to be heterozygous for a novel PKLR mutation (c.1573delT) with an erythrocyte PK activity of 6.2 U/g hemoglobin. Her asymptomatic father was heterozygous for the common Northern European PKLR mutation (c.1529A) with an erythrocyte PK activity of 3.6 U/g. The neonate was a compound heterozygote with both mutations, but with no other mutations identified by sequencing a panel of 27 genes involved in severe neonatal jaundice.

Does HUMARA assay for assessment of clonal hematopoiesis have shortcomings

To the editor:nnDetermination of clonality based on assays of inactivation of genes encoded on the X chromosome has provided important insights into the origins of neoplastic diseases. The following characteristics make a clonality assay informative: (1) the gene being assayed must undergo X

Best practices for use of the HEMOX analyzer in the clinical laboratory: quality control determination and choice of anticoagulant.

The HEMOX Analyzer (TCS Scientific) has been used to measure the full oxygen-dissociation curve (ODC) and to calculate P(50) and the Hill coefficient. The effects of different anticoagulants on sample stability and P(50) values have not been evaluated extensively for this instrument. We characterized an artificial hemoglobin (Equil QC463) for quality control (QC) and compared P(50) values for blood samples drawn into 3 different anticoagulants (acid citrate dextrose [ACD], heparin, and EDTA). P(50) values were not stable in ACD but were stable in heparin and EDTA anticoagulants for up to 4 days. Tests with Equil QC463 showed that P(50) values were quite sensitive to small variations in buffer pH. Use of the correct anticoagulant and strict control of buffer pH are 2 parameters that need to be accounted for in best-practices use of this hemoximeter and before determining P(50).