Understanding, Diagnosing, and Using Genetic Testing for First Degree Atrioventricular Block
Electrical signals reach the ventricles late but intact, giving first degree AV block its long PR interval; SCN5A testing can explain familial cases.
Brandon Colby, MD
MD · MBA
Physician specializing in genetic analysis and personalized preventive medicine, and author of Outsmart Your Genes.
About Brandon
Brandon Colby is a physician-expert in the fields of genetic analysis and Personalized Preventive Medicine. He holds an MD from the Mount Sinai School of Medicine, an MBA from Stanford University's Graduate School of Business, and a degree in Genetics from the University of Michigan.
Dr. Colby is the author of the book Outsmart Your Genes and has developed numerous technologies that improve the analysis, interpretation, and actionability of genome sequencing data. He is an Affiliate Specialist of the American College of Medical Genetics and Genomics (ACMG), an Associate of the American College of Preventive Medicine (ACPM), and a member of the National Society of Genetic Counselors (NSGC).
Education
- BA in Genetics with Honors, University of Michigan · 2000
- MD, Mount Sinai School of Medicine · 2004
- MBA, Stanford University Graduate School of Business · 2007
Affiliations & Memberships
- Affiliate Specialist, American College of Medical Genetics and Genomics (ACMG)
- Associate, American College of Preventive Medicine (ACPM)
- Member, National Society of Genetic Counselors (NSGC)
Articles by Brandon Colby, MD are reviewed for accuracy by Sequencing's medical and scientific team. This page is for informational purposes and does not constitute medical advice.
Articles by Brandon
Understanding, Diagnosing, and Using Genetic Testing for Gastric Cancer
Helicobacter pylori infection, smoking and a family history raise the risk; endoscopy and biopsy confirm stomach cancer, while CDH1 and HER2 results shape therapy.
Understanding Gastrointestinal Hemorrhage: Diagnosis and Genetic Testing
Vomiting blood, tarry stools or rectal bleeding can signal upper or lower GI bleeding; endoscopy, imaging and tests for HHT help locate and explain the source.
Understanding, Diagnosing, and Using Genetic Testing for Geleophysic Dysplasia
Short stature, joint stiffness, thickened skin and heart valve changes point to geleophysic dysplasia, which ADAMTSL2 gene testing can confirm.
Understanding, Diagnosing, and Using Genetic Testing for Generalized Dystonia
Involuntary muscle contractions produce twisting movements, abnormal postures and cramps. Diagnosis combines clinical examination, imaging and DYT1 gene testing.
Understanding, Diagnosing, and Using Genetic Testing for GLUT1 Deficiency Syndrome
When the brain cannot take up enough glucose, seizures, developmental delay and movement disorders can follow; SLC2A1 testing and CSF glucose levels confirm GLUT1 DS.
Understanding Granular Corneal Dystrophy: Diagnosis and Genetic Testing
Breadcrumb-like corneal deposits blur vision in granular corneal dystrophy; slit-lamp exams, topography and TGFBI testing tell type I from the Avellino form.
Understanding Hematologic Neoplasms: Diagnosing and Genetic Testing
Leukemia, lymphoma and myeloma are found with blood counts, bone marrow biopsy and flow cytometry, while DNA markers such as the Philadelphia chromosome guide therapy.