STK11 is a 433 residue serine threonine protein kinase that controls the activity of AMP-activated protein kinase family members and has roles in cell metabolism, cell polarity, chromatin remodeling, cell cycle arrest, apoptosis, and DNA damage responses.3 Reportedly, half of the mutations in STK11 have been identified as point mutations; however, a large genomic deletion has also been found in 30% of patients with PJS.4 Direct sequencing and multiplex ligation-dependent probe amplification are both recommended in the analysis of subjects with PJS. This evidence concerns the gene STK11 and Peutz-Jeghers syndrome.