Turcot's syndrome evidence for autosomal dominant inheritance

Abstract

A case of Turcot's syndrome (colonic polyposis plus a malignant central nervous system tumor) occurring in a kindred with autosomal dominant colonic polyposis is presented. It is proposed that Turcot's syndrome patients can be classified into Type I where only siblings are affected and Type II where two or more generations have colonic polyposis. A third nonfamilial group cannot be classified into Type I or II based on available information. Evidence is presented suggesting Turcot's syndrome is best considered an additional phenotype of familial polyposis and is most likely inherited in an autosomal dominant manner.

Molecular alterations in a patient with Turcot's syndrome

“…The case presented here are that of a 15-year-old girl with polyposis coli, colonic carcinoma metastasising to lymph nodes, the liver and the skin, and a high grade astrocytoma, representing a Turcot's syndrome, type III in the Lewis classification system (Lewis et al, 1983).…”

Evidence for a recessive inheritance of Turcot's syndrome caused by compound heterozygous mutations within the PMS2 gene

“…The more than 130 cases described to date include such types of brain tumors as glioma, medulloblastoma and astrocytoma, associated with a broad spectrum of colorectal ®ndings, from adenoma to typical adenomatous polyposis (Mastronardi et al, 1991;Itoh et al, 1993;Dupuis and Verellen-Dumoulin, 1995). It has yet to be established whether the mode of inheritance of typical Turcot's syndrome is dominant or recessive (Lewis et al, 1983;Itoh et al, 1993;Matsui et al, 1998). Dominantly inherited cases have been associated with germline mutations either within the tumor suppressor adenomatous polyposis coli (APC) gene, which is usually mutated in FAP, or within the mismatch repair (MMR) genes, which are usually mutated in HNPCC (Tops et al, 1992;Mori et al, 1994;Hamilton et al, 1995).…”

An unusual case of Turcot’s syndrome associated with ileal adenocarcinoma, intestinal non-Hodgkin’s lymphoma, and duodenal adenocarcinoma. Review of the classification and genetic basis of Turcot’s syndrome

“…TS may be an extra-colonic variant of Familial Adenomatous Polyposis (FAP) [8][9][10], with autosomal dominant inheritance and characterised by the development of numerous small (<1 cm) colonic polyps from late childhood, leading to colon cancer at around 40 years of age if left untreated. Extra-colonic involvement is recognised, particularly in tumours of the proximal GI tract.…”