[MIM 114 500, 120 435, 609 310, 613 244, 614 331, 614 337, 614 350, 614 385 ]

(Colorectal familial cancer without polyposis, brain tumor-polyposis type 1, HNPCC syndrome)

Rare. Lynch type 1 syndrome is the cause of 1-3 % of all colorectal cancers, especially in patients under 50 years and at the level of the right colon. Autosomal dominant transmission of a mutation of the genes repairing DNA which is not anymore paired following a replication error.

There is significant genetic heterogeneity:

-        MSH2 on 2p22-p21 (35 %): HNPCC1

-        MLH1 on 3q21.3 (25 %): HNPCC2

-        PMS1: HNPCC3 based on a case but which later proved to have a mutation of MSH2 gene

-        PMS2 on 7p22: HNPCC4

-        MSH6 on 2p16 (2 %): HNPCC5

-        TGFBR2: HNPCC6

-        MLH3: HNPCC7

Those mutations can also cause the appearance of malignant endometrial, ovarian, stomach, liver, kidney, brain or skin tumors.

Lynch type 2 syndrome, that includes the Muir-Torre syndrome (see this term) which is the form associated with sebaceous skin tumors, is characterized primarily by extra-colonic localization of the tumors: endometrium, biliary tract, pancreas, stomach, urinary tract.

Anesthetic implications:

endoscopies, colorectal surgery in an adolescent or young adult

References:

-        Galmiche L, Révillon Y, Sarnacki S, Jaubert F.
Le syndrome de Lynch existe en pédiatrie : à propos d’un cas.
Ann Pathol 2004; 24: 621-3.

Updated: April 2021