Overlapping phenotypes between SHORT and Noonan syndromes in patients with PTPN11 pathogenic variants

Overlapping syndromes such as Noonan, Cardio-Facio-Cutaneous, Noonan syndrome (NS) with multiple lentigines and Costello syndromes are genetically heterogeneous conditions sharing a dysregulation of the RAS/mitogen-activated protein kinase (MAPK) pathway and are known collectively as the RASopathies. PTPN11 was the first disease-causing gene identified in NS and remains the more prevalent. We report seven patients from three families presenting heterozygous missense variants in PTPN11 probably responsible for a disease phenotype distinct from the classical Noonan syndrome. The clinical presentation and common features of these seven cases overlap with the SHORT syndrome. The latter is the c…