Complex Neurological Phenotype Associated with a De Novo Mutation in a Boy with Intellectual Disability, Refractory Epilepsy, and Movement Disorder.

Mutations in the gene (MIM: 617836), encoding a subunit of dehydrodolichyl diphosphate synthase complex, have been recently implicated in very rare neurodevelopmental diseases. In total, five individuals carrying two mutations in have been reported so far, but genotype-phenotype correlations remain elusive. We reported a boy with a mutation in (NM_205861.3: c.G632A; p.Arg211Gln) featuring a complex neurological phenotype, including mild intellectual disability, impaired speech, complex hyperkinetic movements, and refractory epilepsy. We defined the electroclinical and movement disorder phenotype associated with the monoallelic form of the -related neurodevelopmental disease and possible underlying dominant-negative mechanisms.