Article
作者: Laszkowska, Monika ; Steinke-Lange, Verena ; Teixeira, Manuel R ; Pinto-Oliveira, André ; Gundlach, Paul ; Ferreira, Marta ; Moreira, Leticia ; van Dieren, Jolanda M ; Delhomelle, Hélène ; Coulet, Florence ; Pinto, Nádia ; Golmard, Lisa ; Gullo, Irene ; Tinschert, Sigrid ; Spier, Isabel ; Hüneburg, Robert ; Aretz, Stefan ; Dias, Alexandre ; Lazaro, Conxi ; Zäncker, Birthe ; López-Fernández, Adriá ; Almeida, Maria L ; van Hest, Liselotte P ; Patiño, Ana ; Cats, Annemieke ; Boussemart, Lise ; Pedro, Ana Maria ; Castellví-Bel, Sergi ; Sousa, Sérgio ; Aronson, Melyssa ; Colas, Chrystelle ; Balmaña, Judith ; SVRCEK, Magali ; Schrader, Intan ; van der Kolk, Lizet E ; Benusiglio, Patrick R ; Mansfield, Paul ; Bourgoin, Pierre ; Palmero, Edenir I ; Farengo Clark, Dana ; Antoniazzi, Augusto Perazzolo ; Herrera-Mullar, Jennifer ; Oliveira, Daniela ; Davis, Jeremy ; Guerra, Joana ; Carrera, Sergio ; Lobo, Silvana ; Batista, Manuela ; Oliveira, Carla ; Katona, Bryson ; Nattermann, Jacob ; Pereira, Paulo S ; Karam, Rachid ; São José, Celina ; Horton, Carolyn ; Strong, Vivian E
Background:
Diffuse gastric cancer (DGC) is the most common manifestation in germline
CTNNA1
variant carriers, with one study estimating a 49–57% lifetime risk by age 80. Knowledge on
CTNNA1
-associated hereditary diffuse gastric cancer (HDGC), loss-of-function mechanisms, variant-type causality, disease spectrum and cancer risks remains scarce.
Objective:
Explore
CTNNA1
genotype–phenotype associations to improve genetic testing criteria, surveillance and risk-reduction recommendations for carriers.
Design:
Using molecular, clinical and population data from 1308 individuals from 351
CTNNA1-
variant carrier families and 37 428 non-carriers from European and American ancestries, we analysed genotype–phenotype associations with multivariable logistic regression. With CRISPR/Cas9
CTNNA1
-knockout gastric cancer (GC) cells and
CTNNA1
-humanised
Drosophila
, we assessed
CTNNA1
-associated loss-of-function mechanisms.
Results:CTNNA1
-truncating transcripts are degraded by nonsense-mediated mRNA decay (NMD), and DGCs from germline
CTNNA1
-truncating carriers lose αE-catenin. These transcripts are non-functional in
Drosophila
, in contrast to non-truncating transcripts. DGC risk is eightfold higher in truncating, compared with non-truncating carriers. The risk of GC and lobular breast cancer (LBC) development in
CTNNA1
-truncating variant carriers is fivefold and eightfold lower than in
CDH1
pathogenic/likely pathogenic variant carriers, respectively. Compared with wild-type individuals, GC risk is 7-fold higher in
CTNNA1
-truncating and 38-fold higher in
CDH1
-truncating variant carriers. LBC is recurrent among
CTNNA1
-truncating carriers, some lacking HDGC criteria. Simplification of previous criteria for
CTNNA1
genetic testing produced the ‘Porto’ criteria, which increased
CTNNA1
-carrier families’ pick-up rate by 9%, without performance loss compared with the HDGC 2020 clinical guidelines. Macular dystrophy patterned-2 was positively associated with non-truncating variants, specifically in the αE-catenin M-fragment.
Conclusion:
We provide compelling evidence supporting that
CTNNA1
-truncating variants positively associate with DGC and LBC, and NMD as the pathophysiological mechanism leading to
CTNNA1
downregulation. We demonstrate that compared with
CDH1
,
CTNNA1
is a moderate penetrance HDGC gene. This new knowledge is essential to define surveillance and/or prophylactic measures for
CTNNA1
-carrier individuals and families.