Test in Focus
Congenital adrenal hyperplasia (CAH) is a group of inherited conditions caused by variants in several enzymes involved in the synthesis of cortisol in the adrenal glands. In this "Test in Focus" episode of the "Answers From the Lab" podcast, Michelle Kluge, MS, CGC, discusses how Mayo Clinic Laboratories' CYPZ test can accurately identify both carriers and individuals who are clinically affected by the most common form of CAH.
"At least 90% of CAH cases are caused by variants in the CYP21A2 gene, which is notorious for being difficult to interrogate," Kluge says. "It has high homology with a nearby pseudogene, and so is difficult to capture by routine genetic testing."
Several laboratories now offer genotyping for common pathogenic variants of CYP21A2 on their carrier screening panels. However, Mayo Clinic Laboratories increasingly receives requests for its CYPZ test as a follow-up, due to conflicting or confusing carrier screening results from external laboratories.
Mayo Clinic Laboratories uses Sanger sequencing to perform molecular genetic testing of CYP21A2. The methodology helps avoid the limitations of standard next-generation sequencing assays of highly homologous regions.
"Our approach allows us to quote a detection rate of greater than 99% for patients with a clinical diagnosis of 21-hydroxylase deficient CAH," Kluge says. "In some cases, this methodology allows us to provide patients with additional phasing information and a more in-depth report."
Listen to learn more about how the CYPZ test can provide accurate, in-depth results for carriers and individuals affected by CAH.
Note: Podcasts will not play back on Internet Explorer. Please use an alternative web browser, or listen from your mobile device on a preferred listening app.
Submit only 1 of the following specimens:
Cherisse Marcou, Ph.D., and Marissa Ellingson, M.S., CGC, discuss whole exome sequencing (WES) at Mayo Clinic Laboratories. The comprehensive evaluation uses next-generation sequencing to detect for single nucleotide variants, small insertions or deletions, and copy number variants on approximately 20,000 genes, enabling precision answers to accurately diagnose, manage, and treat patients with identified inherited illness.
Alicia Algeciras, Ph.D., describes Mayo Clinic Laboratories’ new blood test to detect NFLC, or neurofilament light chain protein. NFLC is a biomarker for several neurodegenerative conditions. The new assay can determine if a patient’s cognitive decline is due to a neurodegenerative condition or some other, reversible condition — while avoiding the need for more-invasive testing of cerebrospinal fluid.
Paul Jannetto, Ph.D., and Loralie Langman, Ph.D., discuss Mayo Clinic Laboratories' unique approach to urine drug testing for addiction rehabilitation. Designed to guide and monitor therapy, the comprehensive profile tests for the most commonly used substances, including alcohol and nicotine, for a complete picture of a patient’s substance use.