We identified FGF14 structural variants in two families with early onset nystagmus and variable neurological and behavioural features: a partial duplication of FGF14 in a two-generation family and a heterozygous 161 kb deletion disrupting FGF14 and ITGBL1 in a previously described four-generation pedigree. The gene discussed is FGF14; the disease is pathologic nystagmus.