AUTHOR=Zhan Qitao , Wang Liya , Xu Xiangrong , Sun Yan , Li Lejun , Qi Xuchen , Chen Feng , Wei Xiaoming , Raff Michael L. , Yu Ping , Jin Fan TITLE=An APC Mutation in a Large Chinese Kindred With Familial Adenomatous Polyposis Was Identified Using Both Next Generation Sequencing and Simple STR Marker Haplotypes JOURNAL=Frontiers in Genetics VOLUME=11 YEAR=2020 URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2020.00191 DOI=10.3389/fgene.2020.00191 ISSN=1664-8021 ABSTRACT=Background

Familial adenomatous polyposis (FAP) is an autosomal dominant disorder characterized primarily by the development of numerous adenomatous polyps in the colon and a high risk for colorectal cancer. FAP is caused by germline mutations of the adenomatous polyposis coli (APC) gene. The proband in this family was a 39-year-old female patient with the pathologic diagnosis of adenomatous polyps, and then a five-generation kindred with FAP was characterized in the following years. This article identified an APC mutation, and demonstrated the practical use of APC-linked STR markers, which could be used to reduce misdiagnosis of prenatal diagnosis or preimplantation genetic diagnosis resulted from contamination or allele drop-out.

Methods

Next-generation sequencing (NGS) was used to identify the possible APC mutations in an affected individual from a family with autosomal dominant colon cancer. Targeted sequencing then used to identify additional related individuals with the mutation. Three short tandem repeat (STR) loci, D5S299, D5S134, and D5S346, were used for PCR-based microsatellite analysis of the APC gene in the extended family.

Results

We identified an APC: p.W553X mutation. The STR haplotype at the APC locus, A1B4C1, was shared by all clinically affected individuals with the APC: p.W553X mutation. In addition, the APC: p.D1822V variant was observed in 40% affected individuals and in two unaffected individuals.

Conclusion

We described a protein truncation mutation, APC: p.W553X; demonstrated the value of APC-linked STR markers (D5S299, D5S134, and D5S346) haplotypes; and suggested the potential role of these haplotypes in detecting loss of heterozygosity of the APC gene.