The I1307K mutation is common among Jews who have had colorectal neoplasms, but overall it was found to have little effect clinically in the current study group.
These findings support a model where somatic instability of the (A)8 tract produced by the APC I1307K allele leads to increased APC gene inactivation and directly accounts for 42% of the colorectal neoplasms occurring in APC I1307K carriers.