Two different nucleotide substitutions of APC gene in a family with familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal dominant syndrome leading to colorectal cancer. This disease appears as a result of germline mutation in adenomatous polyposis coli (APC) gene. The aim of the present study is to report the association between two different nucleotide substitutions detected in a family with FAP. In the proband, p.His1172Gln (c.3516delT) was detected in exon 15 of the APC gene. Furthermore, p.His1172Gln (c.3516delT) and, in addition to this mutation, p.Met1413Val (c.4237 A > G) were detected in exon 15 in both daughters of the proband. However, we believe that single nucleotide change in codon 1413 may be a polymorphic variant and deletion T in codon 1172 of APC gene is associated with FAP, attenuated FAP and extracolonic FAP involvement. Along with common use of genetic tests in the clinical practice, genotype–phenotype correlation may be recognized better and useful for early diagnosis and prevention of familial cancer syndromes.