This compound heterozygous mutation in the VPS13B gene (NM_017890.4) was validated by Sanger sequencing (c.3582delT, p.A1149fs + c.6295_6296delAT, p.M2124 fs) (Fig. 2b) inherited from healthy heterozygous parents confirms the diagnosis of CS. The gene discussed is VPS13B; the disease is Cowden syndrome 1.