The other two patients, PHTS2 and PHTS3 (both affected by CS), showed a significant decrease in the PTEN mRNA expression when analysed by Real Time quantitative RT-PCR (Figure 1a) (unpaired two-tailed t test, confident intervals 99% p: 0,0002); this statistic result was the same when calculated with the twenty healty controls separately and with the four mixes of healty subject (data not shown). This evidence concerns the gene PTEN and Cowden syndrome 1.