Our previous studies revealed that homozygous Dars1-null mutation is embryonically lethal in mice [8] and that the hypomorphic Dars1D367Y mutation in combination with the Dars1-null mutation leads to developmental delay, hydrocephalus, hypomyelination, white matter vacuolization and late onset motor deficits [9]. The gene discussed is DARS1; the disease is Hydrocephalus.