Clinical Heterogeneity in two patients with Noonan-like Syndrome associated with the same SHOC2 mutation

Noonan-like syndrome with loose anagen hair (NS/LAH; OMIM #607721) has been recently related to the invariant c.4A > G missense change in SHOC2. It is characterized by features reminiscent of Noonan syndrome. Ectodermal involvement, short stature associated to growth hormone (GH) deficiency (GHD), and cognitive deficits are common features. We compare in two patients with molecularly confirmed NS/LAH diagnosis, the clinical phenotype and pathogenetic mechanism underlying short stature. In particular, while both the patients exhibited a severe short stature, GH/IGFI axis functional evaluation revealed a different pathogenetic alteration, suggesting in one patient an upstream alteration (typical GHD) and in the other one a peripheral GH insensitivity.