However, special attention must be given to the missense mutations Asp1822Val and Ser2621Cys since their segregation with the FAP phenotype is questionable.
One previously described as a causative germline mutation (S2621C), associated with a 1-bp insertion (4684insA) on the opposite allele, did not segregate with the FAP phenotype in the family and was therefore considered as being non-pathogenic.