Fragile dopamine

摘要

Dopamine dysfunction, which is implicated in Parkinson's disease and drug addiction, seems an unlikely culprit in fragile X syndrome. A surprising set of findings means a rethink is required. Fragile X syndrome is the commonest inherited form of mental retardation, with the patients often also having autism and attention-deficit hyperactivity disorder. It is usually caused by the absence of the protein FMRP, which is encoded by FMR1, a gene on the X chromosome. Although FMRP function is not well understood, most studies concur that it is a selective RNA-binding protein that modulates the translation of its target messenger RNAs. But this deceptively simple description of FMRP function omits any role for the neurotransmitter dopamine, despite the fact that some of the clinical and behavioural features of fragile X syndrome are reminiscent of dysfunction in dopamine-secreting neurons. Writing in Neuron, Wang et al.