<scp> <i>MED27</i> </scp> Variants Cause Developmental Delay, Dystonia, and Cerebellar Hypoplasia

The Mediator multiprotein complex functions as a regulator of RNA polymerase II–catalyzed gene transcription. In this study, exome sequencing detected biallelic putative disease-causing variants in MED27, encoding subunit 27, 16 patients from 11 families with novel neurodevelopmental syndrome. Patient phenotypes are highly homogeneous, including global developmental delay, intellectual disability, axial hypotonia distal spasticity, dystonic movements, and cerebellar hypoplasia. Seizures cataracts were noted severely affected individuals. Identification multiple MED27 supports the critical role normal human neural development, particularly for cerebellum. ANN NEUROL 2021;89:828–833