SUPV3L1 and epilepsy: SUPV3L1: In a pair of siblings (S19a, S19b) with similar phenotype consisting of SM (−3.1 and −4.3 SD, respectively), delayed myelination, white matter abnormalities, profound DD, epilepsy and axial hypotonia, we identified a homozygous variant NM_003171.4: c.1093C>T: p.(Arg365Trp) inherited from healthy carrier parents.