A novel de novo heterozygous mutation in the SON gene associated to Septo-optic dysplasia: a new phenotype?

to date, SON pathogenic variants have been described as responsible for Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome, a multisystemic neurodevelopmental disorder mainly characterized by intellectual disability, facial dysmorphisms, visual abnormalities, brain malformations, feeding difficulties, and growth delay. The herein described case is the first recognized clinic-radiological occurrence of SOD syndrome with hypothalamic-pituitary dysfunction in a patient carrying a SON gene variant, considered responsible of ZTTK syndrome, suggesting a possible relationship between septo-optic dysplasia and SON gene alterations, never described so far, making the search for SON gene mutations advisable in patients with SOD.