Elizna M. Schoeman

Evaluation of targeted exome sequencing for 28 protein‐based blood group systems, including the homologous gene systems, for blood group genotyping

Blood group single nucleotide polymorphism genotyping probes for a limited range of polymorphisms. This study investigated whether massively parallel sequencing (also known as next‐generation sequencing), with a targeted exome strategy, provides an extended blood group genotype and the extent to which massively parallel sequencing correctly genotypes in homologous gene systems, such as RH and MNS.

A D+ blood donor with a novel RHD*D‐CE(5‐6)‐D gene variant exhibits the low‐frequency antigen RH23 (DW) characteristic of the partial DVa phenotype

Blood donors whose red blood cells (RBCs) exhibit a partial RhD phenotype, lacking some D epitopes, present as D+ in routine screening. Such phenotypes can exhibit low‐frequency antigens (LFAs) of clinical significance. The aim of this study was to describe the serologic and genetic profile for a blood donor with an apparent D+ phenotype carrying a variant RHD gene where D Exons 5 and 6 are replaced by RHCE Exon (5‐6).

Targeted exome sequencing defines novel and rare variants in complex blood group serology cases for a red blood cell reference laboratory setting

We previously demonstrated that targeted exome sequencing accurately defined blood group genotypes for reference panel samples characterized by serology and single‐nucleotide polymorphism (SNP) genotyping. Here we investigate the application of this approach to resolve problematic serology and SNP‐typing cases.

A proposed new low-frequency antigen in the Augustine blood group system associated with a severe case of hemolytic disease of the fetus and newborn: Proposed new low-frequency antigen in the Aug Blood Group System

A male infant born at 29 weeks presented with a severe case of hemolytic disease of the fetus and newborn (HDFN) (cord blood direct antiglobulin test 41, hemoglobin 45 g/L with cardiac failure, pleural effusion, and generalized edema). Two exchange and four top-up transfusions were required. The maternal antibody was reactive with paternal red blood cells (RBCs). Later testing revealed that the antibody reacted with RBCs from four additional members of the paternal family. Extensive testing excluded clinically relevant RBC antibodies but failed to reveal a specificity for this antibody. To guide further investigation, specimens from the family (n 5 10) were submitted for blood group genetic studies.

Genotyping by sequencing defines independent novel RHD variants for an antenatal patient and a blood donor

A ccurate D blood group phenotyping is important in transfusion medicine to guide antenatal management for D2 women and donation management for red blood cells (RBCs) from blood donors. A small percentage of individuals carry variant RHD genes associated with either partial D, weak D, or the DEL phenotype, and the latter are detected only by laborious adsorption and elution techniques. Single nucleotide polymorphism (SNP)-microarray typing detects such variant RHD genes but is limited in the number of polymorphisms it interrogates. This report describes the resolution by DNA sequencing of two samples that were unresolved by SNP-microarray genotyping: an antenatal sample (S1) from a patient who presented with variable D reactivity patterns, and a blood donor sample (S2) from a donor who presented as D2 on routine serology but had an E1 phenotype, which sometimes is associated with a DEL phenotype.

A DEL phenotype attributed to RHD Exon 9 sequence deletion: slipped-strand mispairing and blood group polymorphisms: SLIPPED-STRAND MISPAIRING MECHANISM IN RHD

The RhD blood group antigen is extremely polymorphic and the DEL phenotype represents one such class of polymorphisms. The DEL phenotype prevalent in East Asian populations arises from a synonymous substitution defined as RHD*1227A. However, initially, based on genomic and cDNA studies, the genetic basis for a DEL phenotype in Taiwan was attributed to a deletion of RHD Exon 9 that was never verified at the genomic level by any other independent group. Here we investigate the genetic basis for a Caucasian donor with a DEL partial D phenotype and compare the genomic findings to those initial molecular studies.

Severe hemolytic disease of the fetus and newborn due to allo-anti-D in a patient with a partial DEL phenotype arising from the variant allele described as RHD*148+1T (RHD*01EL.31) : HDFN IN MOTHER WITH RHD*148+1T ALLELE

RhD DEL variants may show complete or partial expression of RhD epitopes. There have been only rare reports of anti‐D causing hemolytic disease of the fetus and newborn (HDFN) in this context. We report a case of severe HDFN associated with a recently described DEL variant.

Investigation of the variable In(Lu) phenotype caused by KLF1 variants: THE In(Lu) PHENOTYPE AND KLF1 VARIANTS

KLF1 is an essential transcriptional activator that drives erythropoiesis. KLF1 variants can result in the Inhibitor of Lutheran, or In(Lu), phenotype where red blood cells (RBCs) have reduced BCAM (LU) and CD44 (IN). Other RBC surface molecules also have changed expression; however, there is controversy in the literature regarding which are truly impacted. We aimed to investigate KLF1 variants in the Australian population.

Massively parallel sequencing in complex blood group investigations: Resolving the previously unresolvable.

Conventional cytogenetic karyotyping and targeted FISH analysis have been the established standard of care in investigating chronic lymphocytic leukaemia. These methods whilst providing prognostic and response prediction are subject to a number of limitations including low level of resolution, failure to achieve the representative cell line in culture and the restrictions of targeted investigation by FISH. Whole genome microarray technology has now superseded conventional cytogenetics in the diagnosis of constitutional anomalies due its higher resolution. The technology has the added benefit of detecting copy neutral loss of heterozygosity (CNLOH) and complex rearrangements such as chromothripsis. We performed an unbiased comparison of findings from SNP microarray using the CytoScan750K SNP Array (Affymetrix), conventional karyotype analysis and FISH on 50 CLL patients. The results illustrate a higher detection rate for pathogenic abnormalities in molecular karyotyping compared to conventional 40/50 (80%) and 22/50 (44%), respectively. The detection of additional pathogenic abnormalities not seen by microscopy accounted for 23/50 (46%) and CNLOH detected for chromosome 13, 20 and 22 in 7/50 (14%). We demonstrate the benefits of SNP based whole genome profiling of CLL and propose its inclusion in the testing regime for the diagnosis and management of CLL patients.