Children and adolescents with intellectual disabilities studied with genetic tests according to their clinical phenotype

• Published in: Andes pediatrica : revista Chilena de pediatría Vol. 92; no. 6; pp. 879 - 887
• Main Authors: Santander, Paola, Pedemonte, María José, Troncoso, Mónica, Yáñez, Carolina, Cárdenas, María Alejandra, Guajardo, Karen, Silva, Carolina, Neves, Macarena, López, Claudia, Lagos, Paola, Barrios, Andrés, Troncoso, Ledia
• Format: Journal Article
• Language: Spanish
• Published: Chile 01.12.2021
• ISSN: 2452-6053
• DOI: 10.32641/andespediatr.v92i6.2866

Intellectual disability (ID) is a neurodevelopmental disorder characterized by limitations in intellec tual and adaptive functioning, of various etiologies, including genetic causes. to describe genetic studies carried out in a series of children and adolescents with ID of previously undetermined etiology, considering their phenotypic characteristics. Descriptive study of a series of patients with ID aged 6 to 18 years. Clinical records, cognitive assessment results (Wechsler -TADI), and genetic study performed were reviewed. They were classified according to phenotypic characteristics into Group 1 patients without a specific phenotype, Group 2: patients with Angel- man- and Rett-like neurodevelopmental disorders phenotype, and Group 3: patients with difficult- to-control seizures. Group 1 was studied with CMA and Groups 2 and 3 with specific genetic panels. 18 patients were described, average age 11 years, male predominance, non-consanguineous parents, and with history of psychomotor retardation. Common comorbidities were epilepsy, autism spectrum disorder (ASD), and behavioral difficulties. Most had a neurological examination without focus and had TADI with very poor developmental ages. In Group 1, there was one patient with a 16p11.2 microdeletion and in Group 3 a duplication of the IQSEC2 gene was found in a patient with difficult-to-control seizures. The phenotypic characteristics allow to guide the choice of specific genetic studies in children and adolescents with ID of previously undetermined etiology to approach the etiological diagnosis.