Margaret A. Keller

It's time to phase in RHD genotyping for patients with a serologic weak D phenotype

In 2014, the College of American Pathologists (CAP) Transfusion Medicine Resource Committee (TMRC) reported the results of a survey of more than 3100 laboratories concerning their policies and procedures for testing serological weak D phenotypes and administration of Rh immune globulin (RhIG).1 Among the findings of this survey is the observation that there is a lack of standard practice in the United States for interpreting the RhD type when a serological weak D phenotype is detected. In some laboratories, an individual with a serological weak D phenotype, especially if a blood donor, is interpreted to be RhD-positive. In the same or other laboratories, especially if a serological weak D phenotype is detected in a female of child-bearing potential, the individual is likely to be managed as RhD-negative for transfusions and, if pregnant, considered a candidate for RhIG. Also, the performance characteristics of serological typing methods for RhD vary. For patients, including pregnant women, the majority of laboratories have policies and procedures that do not use the indirect antiglobulin (weak D) test, thereby avoiding detection of a serological weak D phenotype so that the RhD type will be interpreted to be RhD-negative. Other laboratories typically perform a weak D test for the same category of patients. For blood donors and newborns, it is standard practice for laboratories to have policies and procedures for RhD typing to ensure that serological weak D phenotypes are detected and interpreted as RhD-positive.1 n nThe goal of these RhD typing practices is to protect RhD-negative persons from inadvertent alloimmunization to the D antigen by exposure to RhD-positive RBCs, including RBCs expressing a serological weak D phenotype. Although there has not been a recent prospective study in the United States, it is estimated that current RhD typing practice, together with contemporary obstetrical practices for administration of antepartum and postpartum RhIG, is 98.4 to 99 percent successful in preventing RhD alloimmunization and RhD hemolytic disease of the fetus/newborn.2 However, there are unwarranted consequences associated with the practice of not determining the RHD genotype of persons with a serological weak D phenotype, including unnecessary injections of RhIG and transfusion of RhD-negative RBCs -- always in short supply -- when RhD-positive RBCs could be transfused safely. n nCAP’s TMRC reviewed the current status of RHD genotyping and proposed that selective integration of RHD genotyping in laboratory practices could improve the accuracy of RhD typing results, reduce unnecessary administration of RhIG in women with a serological weak D phenotype, and decrease unnecessary transfusion of RhD-negative RBCs to recipients with a serological weak D phenotype.1 In response to the findings of the CAP TMRC survey, AABB and CAP convened a Work Group on RHD Genotyping and charged it with developing recommendations to clarify clinical issues related to RhD typing in persons with a serological weak D phenotype. As an initial step for formulating recommendations, the Work Group reviewed the current state of molecular science of RHD, including more than 140 publications covering background;1-12 D variants with anti-D;13-29 molecular basis of serological weak D phenotypes;30-92 reviews, editorials and commentaries;93-129 technical resources;130-142 and standards and guidelines.143-149 This Commentary summarizes the proceedings and recommendations of the Work Group.

Coriell Personalized Medicine Collaborative®: a prospective study of the utility of personalized medicine

There is a dearth of large prospective studies to determine if genetic risk factors are useful predictors of health outcomes and if reporting them to individuals or physicians changes health behavior. The Coriell Personalized Medicine Collaborative® (CPMC, NJ, USA) is a prospective observational study with three cohorts - community, cancer and chronic disease cohorts. Participants provide detailed medical history through a dynamic internet-based portal. DNA is tested and personalized risk reports are provided for potentially actionable health conditions. To date, the community cohort has enrolled 4372 participants. The internet-based portal supplies educational content, captures phenotypic data and delivers customized risk reports. The Informed Cohort Oversight Board has approved 16 health conditions to date, and risk reports with genetic and nongenetic risks for six conditions have been released. The majority (87%) of participants who completed requisite questionnaires viewed at least one report. The CPMC is a cohort study delivering customized risk reports for actionable conditions using a web interface and measuring outcomes longitudinally.

Genetic risk estimation in the Coriell Personalized Medicine Collaborative.

Purpose: Recent genome wide-association studies have identified hundreds of single nucleotide polymorphisms associated with common complex diseases. With the momentum of these discoveries comes a need to communicate this information to individuals.Methods: The Coriell Personalized Medicine Collaborative is an observational research study designed to evaluate the utility of personalized genomic information in health care. Participants provide saliva samples for genotyping and complete extensive on-line medical history, family history, and lifestyle questionnaires. Only results for diseases deemed potentially actionable by an independent advisory board are reported.Results: We present our methodology for developing personalized reports containing risks for both genetic and nongenetic factors. Risk estimates are given as relative risk, derived or reported from representative peer-reviewed publications. Estimates of disease prevalence are also provided. Presenting risk as relative risk allows for consistent reporting across multiple diseases and across genetic and nongenetic factors. Using this approach eliminates the need for assumptions regarding population lifetime risk estimates. Publications used for risk reporting are selected based on the strength of the design and study quality.Conclusion: Coriell Personalized Medicine Collaborative risk reports demonstrate an approach to communicating risk of complex disease via the web that encompasses risks due to genetic variants along with risks caused by family history and lifestyle factors.

Whole-exome sequencing of DNA from peripheral blood mononuclear cells (PBMC) and EBV-transformed lymphocytes from the same donor

BackgroundThe creation of lymphoblastoid cell lines (LCLs) through Epstein-Barr virus (EBV) transformation of B-lymphocytes can result in a valuable biomaterial for cell biology research and a renewable source of DNA. While LCLs have been used extensively in cellular and genetic studies, the process of cell transformation and expansion during culturing may introduce genomic changes that may impact their use and the interpretation of subsequent genetic findings.ResultsWe performed whole exome sequencing on a tetrad family using DNA derived from peripheral blood mononuclear cells (PBMCs) and LCLs from each individual. We generated over 4.7 GB of mappable sequence to a 125X read coverage per sample. An average of 19,354 genetic variants were identified. Comparison of the two DNA sources from each individual showed an average concordance rate of 95.69%. By lowering the variant calling parameters, the concordance rate between the paired samples increased to 99.82%. Sanger sequencing of a subset of the remaining discordant variants did confirm the presence of de novo mutations arising in LCLs.ConclusionsBy varying software stringency parameters, we identified 99% concordance between DNA sequences derived from the two different sources from the same donors. These results suggest that LCLs are an appropriate representation of the genetic material of the donor and suggest that EBV transformation can result in low-level generation of de novo mutations. Therefore, use of PBMC or early passage EBV-transformed cells is recommended. These findings have broad-reaching implications, as there are thousands of LCLs in public biorepositories and individual laboratories.

Financial implications of RHD genotyping of pregnant women with a serologic weak D phenotype

Hemolytic disease of the fetus and newborn, classically caused by maternal–fetal incompatibility of the Rh blood group D antigen, can be prevented by RhIG prophylaxis. While prophylactic practices for pregnant women with serologic weak D phenotypes vary widely, RHD genotyping could provide clear guidance for management. This analysis evaluated the financial implications of using RHD genotyping to guide RhIG prophylaxis among pregnant females.

The Coriell personalized medicine collaborative pharmacogenomics appraisal, evidence scoring and interpretation system

Implementation of pharmacogenomics (PGx) in clinical care can lead to improved drug efficacy and reduced adverse drug reactions. However, there has been a lag in adoption of PGx tests in clinical practice. This is due in part to a paucity of rigorous systems for translating published clinical and scientific data into standardized diagnostic tests with clear therapeutic recommendations. Here we describe the Pharmacogenomics Appraisal, Evidence Scoring and Interpretation System (PhAESIS), developed as part of the Coriell Personalized Medicine Collaborative research study, and its application to seven commonly prescribed drugs.

It's time to phase in RHD genotyping for patients with a serologic weak D phenotype. College of American Pathologists Transfusion Medicine Resource Committee Work Group.

In 2014, the College of American Pathologists (CAP) Transfusion Medicine Resource Committee (TMRC) reported the results of a survey of more than 3100 laboratories concerning their policies and procedures for testing serological weak D phenotypes and administration of Rh immune globulin (RhIG).1 Among the findings of this survey is the observation that there is a lack of standard practice in the United States for interpreting the RhD type when a serological weak D phenotype is detected. In some laboratories, an individual with a serological weak D phenotype, especially if a blood donor, is interpreted to be RhD-positive. In the same or other laboratories, especially if a serological weak D phenotype is detected in a female of child-bearing potential, the individual is likely to be managed as RhD-negative for transfusions and, if pregnant, considered a candidate for RhIG. Also, the performance characteristics of serological typing methods for RhD vary. For patients, including pregnant women, the majority of laboratories have policies and procedures that do not use the indirect antiglobulin (weak D) test, thereby avoiding detection of a serological weak D phenotype so that the RhD type will be interpreted to be RhD-negative. Other laboratories typically perform a weak D test for the same category of patients. For blood donors and newborns, it is standard practice for laboratories to have policies and procedures for RhD typing to ensure that serological weak D phenotypes are detected and interpreted as RhD-positive.1 n nThe goal of these RhD typing practices is to protect RhD-negative persons from inadvertent alloimmunization to the D antigen by exposure to RhD-positive RBCs, including RBCs expressing a serological weak D phenotype. Although there has not been a recent prospective study in the United States, it is estimated that current RhD typing practice, together with contemporary obstetrical practices for administration of antepartum and postpartum RhIG, is 98.4 to 99 percent successful in preventing RhD alloimmunization and RhD hemolytic disease of the fetus/newborn.2 However, there are unwarranted consequences associated with the practice of not determining the RHD genotype of persons with a serological weak D phenotype, including unnecessary injections of RhIG and transfusion of RhD-negative RBCs -- always in short supply -- when RhD-positive RBCs could be transfused safely. n nCAP’s TMRC reviewed the current status of RHD genotyping and proposed that selective integration of RHD genotyping in laboratory practices could improve the accuracy of RhD typing results, reduce unnecessary administration of RhIG in women with a serological weak D phenotype, and decrease unnecessary transfusion of RhD-negative RBCs to recipients with a serological weak D phenotype.1 In response to the findings of the CAP TMRC survey, AABB and CAP convened a Work Group on RHD Genotyping and charged it with developing recommendations to clarify clinical issues related to RhD typing in persons with a serological weak D phenotype. As an initial step for formulating recommendations, the Work Group reviewed the current state of molecular science of RHD, including more than 140 publications covering background;1-12 D variants with anti-D;13-29 molecular basis of serological weak D phenotypes;30-92 reviews, editorials and commentaries;93-129 technical resources;130-142 and standards and guidelines.143-149 This Commentary summarizes the proceedings and recommendations of the Work Group.

CoAIMs: a cost-effective panel of ancestry informative markers for determining continental origins.

Background Genetic ancestry is known to impact outcomes of genotype-phenotype studies that are designed to identify risk for common diseases in human populations. Failure to control for population stratification due to genetic ancestry can significantly confound results of disease association studies. Moreover, ancestry is a critical factor in assessing lifetime risk of disease, and can play an important role in optimizing treatment. As modern medicine moves towards using personal genetic information for clinical applications, it is important to determine genetic ancestry in an accurate, cost-effective and efficient manner. Self-identified race is a common method used to track and control for population stratification; however, social constructs of race are not necessarily informative for genetic applications. The use of ancestry informative markers (AIMs) is a more accurate method for determining genetic ancestry for the purposes of population stratification. Methodology/Principal Findings Here we introduce a novel panel of 36 microsatellite (MSAT) AIMs that determines continental admixture proportions. This panel, which we have named Continental Ancestry Informative Markers or CoAIMs, consists of MSAT AIMs that were chosen based upon their measure of genetic variance (Fst), allele frequencies and their suitability for efficient genotyping. Genotype analysis using CoAIMs along with a Bayesian clustering method (STRUCTURE) is able to discern continental origins including Europe/Middle East (Caucasians), East Asia, Africa, Native America, and Oceania. In addition to determining continental ancestry for individuals without significant admixture, we applied CoAIMs to ascertain admixture proportions of individuals of self declared race. Conclusion/Significance CoAIMs can be used to efficiently and effectively determine continental admixture proportions in a sample set. The CoAIMs panel is a valuable resource for genetic researchers performing case-control genetic association studies, as it can control for the confounding effects of population stratification. The MSAT-based approach used here has potential for broad applicability as a cost effective tool toward determining admixture proportions.

Amyotrophic lateral sclerosis: An emerging era of collaboratie gene discovery

Amyotrophic lateral sclerosis (ALS) is the most common form of motor neuron disease (MND). It is currently incurable and treatment is largely limited to supportive care. Family history is associated with an increased risk of ALS, and many Mendelian causes have been discovered. However, most forms of the disease are not obviously familial. Recent advances in human genetics have enabled genome-wide analyses of single nucleotide polymorphisms (SNPs) that make it possible to study complex genetic contributions to human disease. Genome-wide SNP analyses require a large sample size and thus depend upon collaborative efforts to collect and manage the biological samples and corresponding data. Public availability of biological samples (such as DNA), phenotypic and genotypic data further enhances research endeavors. Here we discuss a large collaboration among academic investigators, government, and non-government organizations which has created a public repository of human DNA, immortalized cell lines, and clinical data to further gene discovery in ALS. This resource currently maintains samples and associated phenotypic data from 2332 MND subjects and 4692 controls. This resource should facilitate genetic discoveries which we anticipate will ultimately provide a better understanding of the biological mechanisms of neurodegeneration in ALS.

Genetic Knowledge Among Participants in the Coriell Personalized Medicine Collaborative.

Genetic literacy is essential for the effective integration of genomic information into healthcare; yet few recent studies have been conducted to assess the current state of this knowledge base. Participants in the Coriell Personalized Medicine Collaborative (CPMC), a prospective study assessing the impact of personalized genetic risk reports for complex diseases and drug response on behavior and health outcomes, completed genetic knowledge questionnaires and other surveys through an online portal. To assess the association between genetic knowledge and genetic education background, multivariate linear regression was performed. 4 062 participants completed a genetic knowledge and genetic education background questionnaire. Most were older (mean age: 50), Caucasian (90xa0%), female (59xa0%), highly educated (69xa0% bachelor’s or higher), with annual household income over