Among these, 14 patients with RASopathy features presented causative variants in PTPN11 (8/14), SOS1 (2/14), PPP1CB (1/14), and NF1 (1/14), 14 patients diagnosed with tuberous sclerosis complex (TSC) showed variants in TSC1 (3/14) and TSC2 (5/14), five patients with Neurofibromatosis type 2 or Schwannomatosis presented causative variants in NF2 (3/5) and LZTR1 (1/5), while a variant in PTEN and KIT was identified in two other cases with a clinical diagnosis of Cowden syndrome and Piebaldism. The gene discussed is PPP1CB; the disease is Cowden disease.