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PMS2 mutations in childhood cancer
Michel De Vos1, Bruce E Hayward, Ruth Charlton
1University of Leeds, Yorkshire Regional Genetics Service, United Kingdom.
Journal of the National Cancer Institute
|March 2, 2006
Summary
Homozygous PMS2 deficiency presents a distinct cancer syndrome with café-au-lait spots and various tumors. This genetic condition, particularly the R802X mutation, has implications for early diagnosis and family screening.
Area of Science:
- Genetics
- Oncology
- Molecular Biology
Background:
- The PMS2 DNA mismatch repair gene was previously rarely linked to cancer susceptibility.
- Technical limitations and unusual genetic behavior (low heterozygote penetrance) of PMS2 mutations obscured its role.
Purpose of the Study:
- To describe the phenotype of homozygous PMS2 deficiency in Pakistani families.
- To identify specific mutations and their inheritance patterns.
- To differentiate this syndrome from similar conditions like neurofibromatosis type 1.
Main Methods:
- Clinical and genetic analysis of 13 patients from six families of Pakistani origin.
- Mutation analysis focusing on the PMS2 gene.
- Phenotypic characterization including skin pigmentation and tumor spectrum.
Main Results:
- Homozygous PMS2 deficiency is associated with café-au-lait pigmentation and a specific tumor spectrum (leukemias, lymphomas, cerebral malignancies, early-onset colorectal neoplasia).
- A founder effect was identified in five families with the R802X mutation in PMS2.
- The syndrome can be misdiagnosed as neurofibromatosis type 1.
Conclusions:
- Homozygous PMS2 deficiency defines a distinct cancer predisposition syndrome.
- Accurate diagnosis is crucial for family risk assessment and appropriate management.
- The R802X mutation is a significant founder mutation in the studied population.