Genetics

This is a 6-part series describing the products and clinical tools of a laboratory quality improvement project called Region 4 Stork, or R4S.

With the rise of next generation sequencing (NGS) technology, multigene panel testing is expanding so rapidly that clinical practice is racing to keep pace. And questions within genetic tests have expanded along with it, making definitive answers more challenging to come by. Experts in the Genomics Laboratory in Mayo Clinic's Department of Laboratory Medicine and Pathology work to explain this often misunderstood technology.

One of the biggest misunderstandings about genetic testing is a perception that once a variant is identified and analyzed thoroughly, using all the best tools available, it can be associated with a specific disease or condition. But many mutations are deemed “variants of unknown significance,” meaning there is no reported (or insufficient) evidence as to whether or not they cause disease.

In the last decade or so, genetic testing has evolved from single-gene Sanger based assays to much more complex next-generation sequencing (NGS) based assays. This incredible technology has facilitated the rapid and high-throughput evaluation of many genes (hundreds of thousands of DNA strands) all at once.

This week's featured chromosomal microarray test in focus is presented by William Sukov, M.D., a pathologist and cancer geneticist at Mayo Clinic. He discusses when this test should be used for patients with renal tumors.

Newborn screening panels that test for a variety of conditions are available in every state; however, test performance and response rate by each state are very different. Mayo Clinic's Biochemical Genetics Laboratory created the Collaborative Laboratory Integrated Reports tool to mitigate the national (and international) problem of false positives and to raise the bar on test performance.

Ann Moyer, M.D., Ph.D. gives an overview of this new test available through Mayo Clinic Laboratories. She discusses when this testing should be ordered, how this testing improves upon other testing approaches, and what clinical action can be taken due to the results of this testing.

Dietrich Matern, M.D., Ph.D., Division Chair of Laboratory Genetics in the Department of Laboratory Medicine and Pathology in Rochester, Minnesota, has been appointed as a new director on the board of the American College of Medical Genetics and Genomics (ACMG).

Pharmacogenomic testing is still limited, despite ample research, the existence of guidelines, and the emerging evidence it can help patients. Ann Moyer, M.D., Ph.D., Co-Director of the Personalized Genomics Laboratory at Mayo Clinic in Rochester, Minnesota, makes a case for pharmacogenomics.

Researchers at Mayo Clinic have discovered a second-tier test for Pompe disease that has been shown to improve the specificity of newborn screening for the disorder, which would lower the rate of false-positive results.

Ann Moyer, M.D., Ph.D., discusses an additional gene, NUDT15, which is important in the prediction of thiopurine-related toxicity This gene has been added to our TPMT genotyping assay available through Mayo Medical Laboratories.

Devin Oglesbee, Ph.D., Director of the Biochemical and Molecular Genetics Laboratories at Mayo Clinic, provides an overview of the lysosomal storage disease panel, when it is appropriate to order this test, what actions the results allow you to take, and how this test improves upon previous approaches.

Detection of individuals with low thiopurine methyltransferase (TPMT) activity who are at risk for excessive myelosuppression or severe hematopoietic toxicity when taking thiopurine drugs.