Genetic Testing to Diagnose Primary Immunodeficiency Disorders and to Identify Targeted Therapy

Future Frontiers: Exploration of practices, challenges, and educational needs of genetic counselors in emerging subspecialties

The augmented use of genomic testing across different medical subspecialties has led to increased involvement of genetic counselors (GCs) in specialized areas of medicine. However, the lack of educational infrastructure required for changing scholastic needs of GCs entering new subspecialties lends to the burden of self-directed learning and inconsistent knowledge. We conducted a cross-sectional study surveying GCs with experience in the emerging genetic subspecialties of Immunology, Dermatology, Endocrinology, and Pulmonology (abbreviated as "IDEP") on current practices, clinical challenges, and educational strategies undertaken while working in these settings. We compared knowledge and confidence in skills related to IDEP patient care between GCs who do (experienced cohort) and do not (control cohort) practice in these settings to assess their comfort with working in subspecialties. Participants were recruited from the National Society of Genetic Counselors membership. A total of 304 GCs (178 experienced and 126 control) completed the survey. Most GCs in the experienced cohort saw IDEP patients by themselves (n = 104; 58.4%) or with a geneticist (n = 97; 54.4%) and almost all (n = 176; 99%) cited GeneReviews as a primary informational source for IDEP genetics but half (n = 91; 51.1%) agreed that a dedicated online course would be the best way to learn about a specific subspecialty. The experienced cohort scored higher on confidence in all skills (p < 0.001, z = 7.32) and knowledge (p < 0.001, z = 5.68) related to IDEP genetics than the control cohort. Previous exposure to IDEP through graduate school coursework and rotations positively correlated with better self-confidence in skills (p = 0.02, z = -2.19; p < 0.001, z = -5.25) and genetic knowledge (p = 0.03, z = -2.09; p < 0.001, z = -2.81) related to IDEP patient care. Years of experience working as a GC did not correlate with better confidence in skills (p = 0.53) or better IDEP genetic knowledge (p = 0.15). Our findings show that provision of opportunities for increased exposure to subspecialties could help maximize GCs' ability to work in emerging niche fields.

Clinical Aspects of B Cell Immunodeficiencies: The Past, the Present and the Future

B cells and antibodies are indispensable for host immunity. Our understanding of the mechanistic processes that underpin how B cells operate has left an indelible mark on the field of clinical pathology, and recently has also dramatically reshaped the therapeutic landscape of diseases that were once considered incurable. Evaluating patients with primary immunodeficiency diseases (PID)/inborn errors of immunity (IEI) that primarily affect B cells, offers us an opportunity to further our understanding of how B cells develop, mature, function and, in certain instances, cause further disease. In this review we provide a brief compendium of IEI that principally affect B cells at defined stages of their developmental pathway, and also attempt to offer some educated viewpoints on how the management of these disorders could evolve over the years.

Take a Leap of Faith: Implement Routine Genetic Testing in Your Office

Genetic testing is a state-of-the-art and readily accessible diagnostic tool and is increasingly indicated in the evaluation process when relevant and possible, although incorporation of this modality into the daily practice of allergists-immunologists in both academic and nonacademic or community settings is still a challenge. Educational sessions and resources support the use of genetic testing in the diagnosis and management of primary immunodeficiency by both the American Academy of Allergy, Asthma & Immunology and the Clinical Immunology Society. Genetic testing for primary immunodeficiency has become much more convenient and affordable over the past decade; allergist-immunologists in private practice are now able to offer patients high-quality and comprehensive genetic testing panels to help diagnose or characterize underlying immune abnormalities among patients with recurrent infections, and even patients with allergic disorder and noninfectious complications. Although genetic testing has not been a commonplace consideration in day-to-day practice for many nonacademic specialists, a shift toward adopting this into our standard toolkit should be taking place. Most of the commercial genetic testing is aiming for a panel of genes ranging anywhere from just a few to several hundred, so the specialist can feel comfortable clearly interpreting the data. As the panels are analyzing data from next-generation sequencing and deletion/duplication assays, this evaluation may need to be repeated when panels expand and include new relevant genes. Ultimately, for undiagnosed cases, whole-exome and whole-genome sequencing can be the next step; however, involvement of genetic counselors may be needed to interpret the data. The value of genetic testing is that it may bring the clinician closer to an accurate diagnosis; therefore, we can keep treating our patients more accurately and effectively, which may result in less frequent follow-ups for unresolved or recurrent problems. In addition, we can then provide patients and their families with important information about the root cause of their disease state, risks to other family members, and offer genetic counseling services. Genetic testing results may also aid in recognizing when a referral to expert colleagues for more advanced and specialized treatments is indicated.

Whole exome sequencing (WES) approach for diagnosing primary immunodeficiencies (PIDs) in a highly consanguineous community

Primary immunodeficiencies (PIDs) are a heterogeneous group of monogenic inborn errors of immunity. The genetic causes of these diseases can be identified using whole exome sequencing (WES). Here, DNA samples from 106 patients with a clinical suspicion of PID were subjected to WES in order to test the diagnostic yield of this test in a highly consanguineous community. A likely genetic diagnosis was achieved in 70% of patients. Several factors were considered to possibly influence the diagnostic rate of WES among our cohort including early age, presence of consanguinity, family history suggestive of PID, the number of family members who underwent WES and the clinical phenotype of the patient. The highest diagnostic rate was in patients with combined immunodeficiency or with a syndrome. Notably, WES findings altered the clinical management in 39% (41/106) of patients in our cohort. Our findings support the use of WES as an important diagnostic tool in patients with suspected PID, especially in highly consanguineous communities.