A report on a girl of Noonan syndrome 9 presenting with bilateral lower limbs lymphedema

Gene mutations identified in individuals with the NS, regulate impertinently the Ras/MAPK signal transduction pathway and they can currently explain 70% of the NS cases. [...]it is very important for genetic counseling and life management. Similar to tumourigenesis, all genes responsible for RASopathies (developmental syndromes of Ras/MAPK pathway dysregulation) that have been described so far, cause dysregulation of the Ras/MAPK pathway by increasing extracellular signal-regulated kinase (ERK) signaling, either by gain-of-function mutations in RAS genes and RAS-GEFs, such as PTPN11 and SOS1, or by loss-of-function mutations in GTPase activating proteins, such as NF1. [...]according to a recent study,[8] which included 15 prepubertal NS children who received long-term recombinant human growth hormone (rhGH) therapy (rhGH subcutaneously at a dose of 50 to 75 μg/kg/day for 6 days a week for at least >3 years) were safe and effective at improving height, growth velocity, and serum insulin-like growth factor-1 (IGF-1) levels.