Abstract
RATIONALE: Sotos syndrome is a rare genetic disorder characterized by rapid growth during infancy and childhood; ≥2 SD for height and head circumference; distinctive facial appearance and developmental delay.Ten clinically diagnosed cases have been reported from Saudi Arabia; none of them was genetically confirmed. PATIENT CONCERNS: A male Saudi patient, who had a birth length and head circumference above 97th centile, presented with abnormal rapid growth, delayed motor and mental milestones, aggressive behavior, obsession to close doors, nail biting, defective attention, and hyperactivity. DIAGNOSES: Sotos syndrome was suspected INTERVENTIONS:: Molecular genetic analysis for NSD1 gene was carried for the patient. OUTCOMES: A novel heterozygous deletion of all exons 1 to 23 of the NSD1 gene was detected. Genetic counseling was carried for the family with extended genetic testing for the parents and his siblings with normal results. LESSONS: Despite its worldwide distribution, Sotos syndrome may be under-reported. Besides its characteristic clinical picture, molecular genetic testing is also extremely recommended.