Bi-allelic germline mutations in the MUTYH gene give rise to multiple adenomas and an increased incidence of colorectal cancer. In addition, duodenal adenomas and other extra-colonic manifestations have been described in MUTYH-associated polyposis (MAP) patients. We describe two patients with bi-allelic MUTYH gene mutations with duodenal carcinoma. The tumour in Patient A was detected during evaluation of non-specific abdominal complaints. Patient B was already diagnosed with tens of adenomas and a colon carcinoma, when a duodenal neoplasm was detected. The identification of somatic G>T mutations in codon 12 of the K-RAS2 gene provides evidence that the duodenal lesions were induced by MUTYH deficiency. Studies in larger series of MAP patients are needed to investigate the risk of upper-gastro-intestinal malignancies and to determine further guidelines for endoscopical surveillance.
- AFAP, attenuated familial adenomatous polyposis
- CRC, colorectal cancer
- FAP, familial adenomatous polyposis
- MAP, MUTYH-associated polyposis
- PCR, polymerase chain reaction
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↵* These authors contributed equally.
Published Online First 30 August 2006
This study was funded by the Dutch Digestive Diseases Foundation, grant MWO 0355 (http://jcp.bmjjournals.com/misc/ifora/licenceform.shtml).
Competing interests: None.