Prior research [22,23] has shown that the VNTR regulates the alternative splicing of a brain-unique isoform AS3MTd2d3 lacking arsenite methyltransferase activity; this isoform has higher levels in individuals with schizophrenia compared to controls; it is upregulated during human stem cell differentiation toward neuronal fates; and it reduces densities of mushroom dendritic spines in cultured primary hippocampal neurons. The gene discussed is AS3MT; the disease is schizophrenia.