MED29 and microcephaly: Here we present a novel homozygous variant in MED29 (OMIM 612914), which has been previously unrelated to human disease, associated with severe GDD, microcephaly, pontocerebellar hypoplasia, cataracts and variably epilepsy, including functional and structural modeling in Morpholino-knockdown (Mok) zebrafish, transfected mouse primary hippocampal cultures and knockdown mouse embryos.