Fish with 50%–75% fmr1 knockdown may be related to fragile X tremor/ataxia syndrome (FXTAS), which expresses a moderate increase of r(CGG) expansion (~120 copies) and often displays elevated fmr1 mRNA but not FMRP protein levels, accordingly. The gene discussed is FMR1; the disease is fragile X-associated tremor/ataxia syndrome.