Chromosomal clubs?

…a few months earlier, a newly available DNA test revealed that Samantha and Taygen share an identical nick in the short arm of their 16th chromosomes…

Some mutations are so rare that they are known only by their chromosomal address: Samantha and Taygen are two of only six children with the diagnosis “16p11.2.”

It turns out that individuals (and their parents) who share these diagnoses are meeting and exchanging information and forming mini-alliances.  Here is the full story, though I am not entirely comfortable with the tone and selection of the article as a whole — only negatives, for one thing.  Rare copy variations also may be a significant source of human progress and, for that matter, individual contentment.

For the pointer I thank Andrew S.