Yes, AGRAPHIA is a Scrabble word!

Letter values in Scrabble US: A 1, G 2, R 1, A 1, P 3, H 4, I 1, A 1.

Is it a valid word?

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

a loss of the ability to write or to express thoughts in writing because of a brain lesion

Not playable in Scrabble US: ANORTHOGRAPHY, LOGAGRAPHIA.