Novel Variants in Patients with Intellectual Disability.

Intellectual disability (ID) occurs in approximately 1% of the population. Over the last years, broad sequencing approaches such as whole exome sequencing (WES) substantially contributed to the definition of the molecular defects underlying nonsyndromic ID. Pathogenic variants in , which encodes the human immunodeficiency virus type I enhancer binding protein 2, have recently been reported as a cause of ID, developmental delay, behavioral disorders, and dysmorphic features. HIVEP2 serves as a transcriptional factor regulating NF-ĸB and diverse genes that are essential in neural development. To date, only 8 patients with pathogenic de novo nonsense or frameshift variants and 1 patient with a pathogenic missense variant in have been reported. By WES, we identified 2 novel truncating variants, c.6609_6616delTGAGGGTC (p.Glu2204*) and c.6667C>T (p.Arg2223*), in 2 young adults presenting with developmental delay and mild ID without any dysmorphic features, systemic malformations, or behavioral issues.