The shortest referral letter ever?

I was chatting with my local GP at his surgery, and discovered he is something of an evangelist for clarity in written communication. As practice scribe, he works tirelessly to tidy up sloppy writing from colleagues and within the NHS, in a bid to get messages across clearly and succinctly. 

He lays claim to having written the shortest referral letter ever to a consultant. Referring a patient (male, as you will discover) to a consultant who was well-known for getting to the point, he penned thus: 

“Dear XXXX, 

re: Mr Smith

Circumcision?”

The reply beat even that: 

“Dear XXXX, 

re: Mr Smith

Yes!”

PS his handwriting is still an indecipherable scribble, though.