polygenic disease

NOUN
17 LETTERS · STARTS WITH P

polygenic disease is a valid 17-letter word worth 25 points in Scrabble and 29 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
P3O1L1Y4G2E1N1I1C3D2I1S1E1A1S1E1
3 + 1 + 1 + 4 + 2 + 1 + 1 + 1 + 3 + 0 + 2 + 1 + 1 + 1 + 1 + 1 + 1 =25 PTS
DOUBLE WORD → 50TRIPLE WORD → 75
MEANING

What does polygenic disease mean?