Identification of disease-causing variants in the EXOSC gene family underlying autosomal recessive intellectual disability in Iranian families.

Neurodevelopmental delay and intellectual disability (ID) can arise from numerous genetic defects. To date, variants in the EXOSC gene family have been associated with such disorders. Using next-generation sequencing (NGS), known and novel variants in this gene family causing autosomal recessive ID (ARID) have been identified in five Iranian families. By collecting clinical information on these families and comparing their phenotypes with previously reported patients, we further describe the clinical variability of ARID resulting from alterations in the EXOSC gene family, and emphasize the role of RNA processing dysregulation in ARID.

SZT2 mutation in a boy with intellectual disability, seizures and autistic features.

The seizure threshold 2 (SZT2) gene has been shown to confer a low seizure threshold and may enhance epileptogenesis in mice. However, its biological function is still not known. Mutations in SZT2 have been reported in very few patients and features range from mild to moderate intellectual disability without seizures to severe intellectual disability with epileptic encephalopathies with severe developmental delay. Here, we report a six-year-old boy with a novel homozygous mutation in SZT2 gene with intellectual disability, seizures, absent speech and autistic features. We are reporting the first patient with autistic features including very little or no eye contact, arm flapping and repetitive behaviour.