▁Medicine ▁at ▁Cre ight on ▁University ▁Medical ▁Center , ▁character ized ▁the ▁synd rome ▁in ▁ 1 9 6 6 . ▁In ▁his ▁earlier ▁work , ▁he ▁described ▁the ▁disease ▁entity ▁as ▁" can cer ▁family ▁synd rome ." ▁The ▁term ▁" L yn ch ▁synd rome " ▁was ▁co ined ▁in ▁ 1 9 8 4 ▁by ▁other ▁authors ; ▁Lyn ch ▁named ▁the ▁condition ▁H NP CC ▁in ▁ 1 9 8 5 . ▁Since ▁then ▁the ▁two ▁terms ▁have ▁been ▁used ▁inter change ably , ▁until ▁later ▁adv ances ▁in ▁the ▁understanding ▁of ▁the ▁gen et ics ▁of ▁the ▁disease ▁led ▁to ▁the ▁term ▁H NP CC ▁falling ▁out ▁of ▁favor . ▁ ▁Other ▁sources ▁reserve ▁the ▁term ▁" L yn ch ▁synd rome " ▁when ▁there ▁is ▁a ▁known ▁DNA ▁mismatch ▁repair ▁defect , ▁and ▁use ▁the ▁term ▁" famil ial ▁col ore ct al ▁cancer ▁type ▁X " ▁when ▁the ▁Amsterdam ▁criteria ▁are ▁met ▁but ▁there ▁is ▁no ▁known ▁DNA ▁mismatch ▁repair ▁defect . ▁The ▁put ative ▁" type ▁X " ▁families ▁appear ▁to ▁have ▁a ▁lower ▁overall ▁inc idence ▁of ▁cancer ▁and ▁lower ▁risk ▁for ▁non - col ore ct al ▁can cers ▁than ▁families ▁with ▁documented ▁DNA ▁mismatch ▁repair ▁def ic iency . ▁About ▁ 3 5 % ▁of ▁people ▁who ▁meet ▁Amsterdam ▁criteria ▁do ▁not ▁have ▁a ▁DNA - m ism atch - rep air ▁gene ▁mut ation . ▁ ▁Comp lic ating ▁matters ▁is ▁the ▁presence ▁of ▁an ▁alternative ▁set ▁of ▁criteria , ▁known