Effect of nonsense mutations on PTEN mRNA stability

Cowden disease is an autosomal dominant disorder associated with an elevated risk of breast, thyroid and skin cancers, in which germline mutations of a tumour suppressor gene (PTEN) have been identified. PTEN has a dual-specificity tyrosine phosphatase domain thought to be essential for tumour suppression. Previous genotype/phenotype correlations have identified several potential associations, for example that truncating mutations result in increased breast cancer risk. Such associations are useful in evaluating the phenotypic functions of PTEN sub-domains. However, genotype/phenotype correlations are likely to be complicated by nonsense mediated mRNA degradation. We report here that three out of four mutations do not significantly affect PTEN transcript stability. Furthermore, we show that manual sequencing methods are better than current dye-based sequencing technologies for detecting heterozygous mutations in PTEN transcripts.