LS is an autosomal dominant genodermatosis. The characteristic lentigines usually develop during childhood and in the first months of life. Clinical diagnosis is primarily based on the typical facial features and the presence of hypertrophic cardiomyopathy and/or café-au-lait macules. The disorder is caused by mutations in the PTPN11 gene, coding for the protein tyrosine phosphatase SHP-2, and situated on chromosome 12. LS is allelic to Noonan syndrome and shares several clinical features