ACTL6B and microcephaly: We find that DEE76, caused by the ACTL6B biallelic variant, is an early-onset drug-refractory epilepsy with global developmental delay<sup>HP:0001263</sup>, hypertonia<sup>HP:0001276</sup>, and microcephaly<sup>HP:0000252</sup>, and imaging is characterized by brain delayed myelination<sup>HP:0012448</sup>.