The sequencing of the human genome didn’t immediately lead to treatments for a number of diseases, as many had hoped and a smaller number had predicted. However, the enormous drop in the price of DNA sequencing over the past decade has now made it possible to sequence an individual’s complete genome for less than $5,000.
Uncovering the molecular underpinnings of human diseases is not a new endeavor, but the pace at which these discoveries are being made is breathtaking. It is now cost and time effective to use DNA sequencing as a diagnostic tool for individuals suffering from a wide variety of congenital maladies. Instead of putting patients through batteries of expensive and sometimes invasive testing, DNA sequencing is becoming the go-to method for discerning the molecular truth. Science journals are packed with articles in which sequencing has led to the identification of a growing number of genes that, when altered, appear to be the causative agents responsible for these diseases. Here is just a sampling of medical conditions that have been tied to specific genetic defects over just the past few years:
Ogden syndrome (NAA10), dominant X-linked juvenile and adult onset ALS and ALS dementia (UBQLN2), dopa responsive dystonia (SPR), early onset severe bowel inflammation (XIAP), craniosynstosis (HUWE1), developmental disorder (DDOST), Hadju-Cheney syndrome (NOTCH2), Proteus syndrome aka elephant man disease (AKT1), Thrombocytopenia-absent radius [TAR] syndrome (EBN8A), hereditary diffuse leukoencephalopathy with spheroids (CSF1R), ALS and frontotemporal dementia (C9ORF72), juvenile ALS (SIGMAR1), adenoid cystic carcinomas (MYB-NFIB), postlingual nonsyndromic hearing impairment (PRPS1), familial diarrhea syndrome (GUCY2C), and even a type of stuttering (NAGPA).
These discoveries build on the work of the past few decades, which saw the root cause for a number of diseases identified by other genetic approaches. These include cystic fibrosis (CFTR), Huntington’s disease (HTT), Tay Sachs (HEXA), Duchenne muscular dystrophy (DMD), and sickle cell anemia (HBB). Sequencing efforts may not directly help identify all of the components that contribute to multi-factorial illnesses like heart disease and diabetes, or chromosomal abnormalities like Turner or Klinefelter’s syndromes. However, the overall impact of this sequencing work has been spectacular, and we’re not done yet. The National Organization for Rare Disorders reports that there are 6,000-7,000 known rare diseases that affect some 25-30 million Americans. Approximately 250 of these diseases have FDA-approved therapies. The molecular pathology behind a much larger number of these diseases has still not been discovered. That leaves a lot of people looking for both
