Most of those genetic lesions generate the termination codon or the frameshifts which yield the truncated form of APC gene products. In the case of missense mutations, however, it may be difficult to exclude completely the possibility that they are normal DNA polymorphisms, even if the unaffected individuals possess none of those nucleotide sequences. To determine whether this genetic diversity is a pathogenetic missense mutation or a normal polymorphism, we examined the nucleotide sequences surrounding this site on more than 70 alleles of non-polyposis individuals and all alleles were the CGG type at codon 88. An arrow indicates an additional band.
Asterisks represent normal fragments.
No aberrant fragment was detectable in exon 5. Nucleotide sequence analysis of PCR products of the ACP gene. Another affected relative also possessed the same nucleotide sequence. Therefore, if possible, it is necessary to prepare another set of primers in order to avoid missing small genetic alterations. Groden J, Thliveris A, Samowitz W, Carlson M, Gelbert L, Albertsen H, et al.