Oops, it doesn't look like 'syndrome day' is a national day..

Other days

lisp

Lisp Day
pick me

Pick Me Day
cuddle up

Cuddle Up Day
ask out your crush

Ask Out Your Crush Day
stud

Stud Day
boba

Boba Day
me

Me Day
my little pony

My Little Pony Day
tulip

Tulip Day
emoji

Emoji Day