Type I neurofibromatosis (NF-1) and Noonan syndrome (NS) are two fairl
y common genetic disorders. Patients with features of both disorders h
ave been described, but considerable variability of phenotypic express
ion occurs. As a result, the correct nosology of this syndrome is unce
rtain. We present a patient with full expression of both NF-1 and NS p
henotypes, and discuss the debate regarding the genetics of the combin
ed syndrome.