Yes, LUES is a Scrabble word!

Letter values in Scrabble US: L 1, U 1, E 1, S 1.

Is it a valid word?

LUES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a common venereal disease caused by the treponema pallidum spirochete; symptoms change through progressive stages; can be congenital (transmitted through the placenta)

Also: lues venerea.