In this work, we found that rs4583255[T] also confers risk of reduced BMI (P = 0.0039 in GIANT, P = 0.00047 in additional Icelanders). This result supports the suggestion, made previously47, that the duplication’s effects on psychosis and BMI have a single origin, presumably in the brain. We did not find evidence of association of rs4583255[T] with autism, although we were somewhat underpowered to detect an effect of the same size as in psychosis, especially for sub-phenotypes.
