MUTYH and polyposis: In 2002, Al-Tassan and coworkers described for the first time a recessive form of polyposis associated with biallelic mutations of MUTYH (Al-Tassan et al., 2002; Jones et al., 2002; Sieber et al., 2003); this gene encodes a base excision repair (BER) protein that counteracts DNA damage induced by oxidative stress.