Human fetal brain tissue was acquired from the Human Developmental Biology Resource (HDBR) (http://www.hdbr.org) and MRC Brain Banks network (http://www.mrc.ac.uk/research/facilities/brain-banks/access-for-research). Ethical approval for the HDBR was granted by the Royal Free Hospital research ethics committee under reference 08/H0712/34 and Human Tissue Authority (HTA) material storage licence 12220; ethical approval for MRC Brain Bank was granted under reference 08/MRE09/38. A detailed description of these samples can be found in Spiers et al (2015)6. Briefly 173 fetal brain samples (94 male, 79 female) ranging from 56 to 169 days post-conception were used for DNA methylation and SNP profiling. Brain tissue was obtained frozen and had not been dissected into regions. Half of the brain tissue from each individual fetus was homogenized for subsequent genomic DNA extraction. Postnatal prefrontal cortex (PFC), striatum (STR) and cerebellum (CER) samples were obtained from the MRC London Neurodegenerative Disease Brain Bank and the Douglas Bell-Canada Brain Bank (DBCBB) (www.douglasbrainbank.ca) and included both schizophrenia and controls. Postmortem brain specimens were collected postmortem following consent obtained with next of kin, dissected by neuropathology technicians, snap-frozen and stored at −80°C.
