
Unraveling the Mysteries of Ataxia-Telangiectasia Without Immunodeficiency
When neurological and vascular signs appear but the immune system is normal, A-T can be missed; ATM sequencing confirms the diagnosis and informs counseling.

MD · MBA
Physician specializing in genetic analysis and personalized preventive medicine, and author of Outsmart Your Genes.
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).
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.

When neurological and vascular signs appear but the immune system is normal, A-T can be missed; ATM sequencing confirms the diagnosis and informs counseling.

Vision loss, obesity, kidney abnormalities, intellectual disability and extra digits mark Bardet-Biedl syndrome. Studies link it to BBS1, BBS10, BBS12 and MKKS.

More than 20 genes are linked to BBS, BBS1 and BBS10 most often; rare multiallelic variants, oligogenic inheritance and setmelanotide findings are described.

Phenotypic diversity in BBS14 shows up across patient cohorts; CCDC28B affects ciliogenesis, and urine metabolomics points to biomarkers of renal disease.

Some forms of BBS need mutations in two genes rather than one; a fetus with third-trimester ascites was diagnosed, and PGD later assisted an unaffected live birth.

Discover the role of genetic testing in diagnosing and managing Bardet-Biedl Syndrome, a rare genetic disorder. Learn about gene variations, prenatal diagnosis, and carrier…

Population studies from India, Pakistan and China report BBS9, MKKS/BBS6 and BBS12 variants, showing why the gene behind a case is worth pinning down.

Reduced beta-globin output causes anemia ranging from mild to severe, and pairing the Hb Knossos variant with a beta-zero mutation signals a more demanding course.