[ study on mutations in hotspot sites of exon 15 of apc gene in familial adenomatous polyposis patients and their relatives in Iran Khuzestan province]

ABSTRACT

The aim of this study was to estimate mutation frequency in exon 15 of APC gene in Khuzestan FAP patients and their relatives. We have analyzed 12 patients and 11 individual among their relatives. DNA extraction from EDTA treated whole blood was performed by routine salting out method. Three hotspot regions of axon 15 from APC gene were amplified separately with three primer pairs by PCR and the fragments have been analyzed for putative mutations by single stranded conformation polymorphism [SSCP] according to standard protocols and subsequent sequencing. We found aberrant bands by SSCP method in seven patients and two related members, that compared with data from sequence analysis yield following five patients [24 to 35 years old] carried novel frame shift mutation [3195-3196insT] leading to premature protein. In two patients whose SSCP were positive, no mutations in their two relatives were identified. In this report we have used SSCP as pre-screening method for mutation analysis of our samples and found putative mutations in nine of them. After sequencing, only in five samples "true mutation" could be confirmed It is intersting that approximately 50% of Khuzestan FAP patients carry mutation in axon 15 of APC gene. Noteworthly, in this work only a small region of the APC gene was subject of the investigation and interestingly, all patients showed the same new mutation. Studies with large number of samples can help us to know, whether this new mutation is predominant or even exclusive within Khuzestan FAP patients.