Patients with a milder phenotype of MOPD1 have also been recently described15, 16, 17, 18; they exhibit severe microcephaly, with poorly developed gyri and agenesis of corpus callosum, and typical dysmorphic features (striking micrognathia, absent eye brows, large prominent nose, dysplastic nails and, in some, agenesis of ear lobes). This evidence concerns the gene RNU4ATAC and microcephaly.