His Wikipedia page says “In 2006, the Basso family also joined a progeria clinical study programme at the National Institutes of Health in Bethesda, Maryland, where the Human Genome Research Institute (NHGRI) is based. At that centre, the complete collection of data on Sammy's organs and apparatuses was carried out for the first time for research purposes.”
Maybe they knew some people up in Frederick; or maybe NIH sent him up there for some examinations. There's also a locally famous Italian-fusion restaurant in Frederick, Volt, operated by one of the Voltaggio brothers who once competed against each other on Top Chef.
NIH at red dot with white cross just NW of DC; Frederic is up the road about 30 miles. Interestingly, Apple Maps won't show you Fort Detrick or Camp David. It's NW of Frederick.
