SGCE and Neurodevelopmental delay: In 2 of 5 patients with missense FOXG1 mutations, the combination of myoclonus and dystonia was a prominent clinical feature (videos 6–8), and reminiscent of SGCE mutation–positive myoclonus-dystonia syndrome (MDS) caused by DYT11 mutations.16, –, 18 MDS is reported to show genetic heterogeneity,17 and we propose that FOXG1 mutations should be included in the differential diagnosis when investigating SGCE mutation–negative MDS, especially in the context of neurodevelopmental delay.