An autosomal dominant disorder with an acronym of its seven features (lentigo; ELECTROCARDIOGRAM abnormalities; ocular hypertelorism; PULMONARY STENOSIS; abnormal genitalia; retardation of growth; and deafness or SENSORINEURAL hearing loss). This syndrome is caused by mutations of PTPN11 gene encoding the non-receptor PROTEIN tyrosine PHOSPHATASE, type 11, and is an allelic to noonan syndrome. Features of leopard syndrome overlap with those of neurofibromatosis 1 which is caused by mutations in the neurofibromatosis 1 genes.