At EHMT1 we observed a total of two de novos, three additional exonic CNVs in cases and one in a control. EHMT1 haploinsufficieny has been implicated as the cause of the 9q subtelomeric deletion syndrome (9qSTDS) characterised by moderate-to-severe mental retardation, childhood hypotonia and facial dysmorphisms, as well as a high prevalence of psychiatric symptoms in adulthood.31 A recent study has also reported strong evidence that deletions at EHMT1 are highly penetrant for phenotypes comprising developmental delay and a range of congenital anomalies.32 With this additional evidence for the involvement of this gene in neurodevelopmental phenotypes, our data point to EHMT1 as a schizophrenia susceptibility gene. Intriguingly, in Drosophila, ehmt coordinates epigenetic changes important in regulating cognition.33 Our findings at this locus thus suggest a role for epigenetic mechanisms in at least some cases of schizophrenia, and potentially point the way to novel therapeutic opportunities as the developmental effects of ehmt mutation on cognition are reversible.31
