Writing in The New England Journal of Medicine, a UC San Diego Health physician and colleagues describe a confounding case literally threatening life and limb and how genetic sequencing provided answers.
A “rare disease” is officially defined as a disease or condition that affects fewer than 200,000 persons in the United States. It’s a bit misleading since there are more than 10,000 known rare diseases and the total number of people with rare diseases in the U.S. exceeds 30 million.
One indisputable aspect of rare diseases that that frontline clinicians rarely see cases, which makes accurate diagnoses far more difficult. In a recent case report, published in The New England Journal of Medicine, lead author Tom Alsaigh, MD, an internist and vascular medicine physician at UC San Diego Health, and co-authors describe a confounding case of a 48-year-old man with long-standing type 2 diabetes who began displaying numbness, tingling and discoloration in the tips of fingers and toes.
These symptoms, collectively known as paresthesia, are not uncommon among persons with diabetes, but this patient’s particular combination of symptoms was confounding. And the paresthesia soon progressed to foot ulcers, difficulty breathing, kidney dysfunction and worse.
The report recounts doctors’ diverse and progressive efforts to treat accelerating symptoms and determine their underlying cause. Ultimately, whole genome sequencing (WGS) was used to identify a rare mutation causing progressive arterial calcification. The disease identified can lead to stiffening of arteries and compromised blood supply to the extremities. Once identified, treatment was focused on reducing the arterial calcium deposition, leading to wound healing and patient improvement.
WGS is a powerful tool for personalized medicine; it is a method used to determine the entirety (or nearly) of the DNA sequence of an organism, whether bacteria, insect or human. Though more often associated with basic research, the report by Alsaigh and colleagues presents a real-life example of how genomics can intersect with clinical care, providing a powerful tool for clinicians confronting diseases that defy easy diagnosis and treatment.
You can read more about the case here.
— Scott LaFee