Trouble Spots
Ten gene variants implicated as risk factors for two widespread mental illnesses.
By Charles Schmidt // Fall 05
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A growing number of gene variants have been implicated as risk factors for mental illness. Here are 10 that seem to play a role in depression and schizophrenia.
DISORDER |
VARIANT |
SUSPECTED ROLE |
DEPRESSION | Serotonin transporter | May exacerbate lifelong tendency toward anxiety and vulnerability to stress. | Brain-derived neurotrophic factor (BDNF) | May interfere with development, survival and plasticity of neurons in brain regions related to mood. | Tryptophan hydroxylase 2 | Seems to produce sharply lower levels of serotonin, a neurotransmitter, but that finding has yet to be replicated. | SCHIZOPHRENIA | Catechol-O-methyl transferase (COMT) | Possibly interferes with the normal function of dopamine, a neurotransmitter involved in cognition and reward. | Dysbindin | Reduced expression may compromise normal functioning of synapses. (Many experts believe schizophrenia is at least in part a synaptic signaling disorder.) | Neuregulin 1 | May cause malformed synapses and may interfere with function of neurotransmitters such as glutamate. | RGS4 | Expression of this gene, which normally helps to reduce the activity of several neurotransmitters, may be lower in the brains of schizophrenics. | DISC1 | Linkage and association studies have implicated this gene, which may be related to hippocampal development and function. | GRM3 | May interfere with normal function of glutamate. | G72 | Studies in German, Han Chinese and other populations report associations between schizophrenia and this gene, which may disrupt synaptic function. |
