Congenital hypertrophy of the retinal pigment epithelium and APC mutationsin two Chinese families with familial adenomatous polyposis

Purpose Congenital hypertrophy of the retinal pigment epithelium (CHRPE) ex ists almost exclusively among familial adenomatous polyposis (FAP) patients with adenomatous polyposis coli (APC) mutations between codon 413 in exon 9 and codon 1387 in exon 15. We investigated the locality of APC mutations in relationship to the occurrence of CHRPE in two Chinese families with FAP . Methods Genomic DNA of available members of two unrelated Chinese FAP famil ies was investigated for sequence alteration in the APC gene by polymerase chain reaction and direct sequencing. All subjects were examined by binocul ar indirect ophthalmoscopy (BIO) for CHRPE. Results A mutation in exon 6, Arg216Stop, was identified in one patient wit h FAP and CHRPE. An Arg283Stop mutation in exon 8 was found in 5 members in another family; 4 of them had FAP and all had small hypopigmented white le sions, probably a new type of CHRPE. Conclusions We found two mutations, Arg216Stop and Arg283Stop, upstream of codon 413 in FAP patients presenting with CHRPE. Arg283Stop has not previou sly been reported in such patients. A large-scale study on CHRPE and APC mu tations in Chinese FAP patients is required to affirm their interrelationsh ips and the significance of the hypopigmented white lesions.