EEF2-Related Neurodevelopmental Disorder Is Clinically Recognizable

Introduction: EEF2 encodes eukaryotic elongation factor 2 which catalyzes the elongation phase of protein translation. It is ubiquitously expressed and important for neuronal function. EEF2 was first associated with adult-onset spinocerebellar ataxia type 26 (SCA26). A novel neurodevelopmental disorder associated with de novo heterozygous variants in EEF2 has been described. Only 6 patients have been described in the literature thus far. A 9-year-old child with de novo novel missense variant is described here. EEF2-related neurodevelopmental disorder appears to be clinically recognizable. Case Presentation: A nine-year-old male with autism spectrum disorder was referred for genetic evaluation. On examination, he had relative macrocephaly and frontal prominence. Whole exome sequencing revealed a de novo c.1225 C>T: p. (R409W) variant in exon 9 of the EEF2 gene (NM-001961.3). Discussion: A comparison of clinical findings suggests that relative macrocephaly/macrocephaly and prominent forehead are consistent and easily identifiable clinical features of EEF2-related neurodevelopmental disorder. The clinical spectrum of this disorder is still emerging. EEF2-related neurodevelopmental disorder should be considered in a child with autism, developmental delays/ intellectual disability, macrocephaly/relative macrocephaly, and frontal prominence.