PLAA and Hypsarrhythmia: In three consanguineous families, seven infants presented with a severe neurodevelopmental disorder—originally diagnosed as either PEHO (progressive encephalopathy with edema, hypsarrhythmia, and optic atrophy [MIM: 260565]) or acrocallosal-like syndrome (MIM: 200990)—and were independently found to carry an identical c.68G>T (p.Gly23Val) missense substitution in PLAA (Phospholipase A2-activating protein [GenBank: NM_001031689.2]) (Figures 1 and S1), encoding a highly conserved ubiquitin binding protein.