Table 1 Comparison of three recent genome-wide searches for CNV differences between large cohorts of people with schizophrenia and control populations

Stefansson et al. [21]

1,433 patients with schizophrenia; 33,250 controls. Follow-up with 3,285 cases and 7,951 controls

England, Finland, Germany, Iceland, Italy and Scotland

High-density SNP microarrays

Deletions at chromosomes 1q21.1, 15q11.2 and 15q13.3 associated with schizophrenia (findings in bold are those that are present in more than 1 study)

The International Schizophrenia Consortium [22]*

3,391 patients with schizophrenia (according to the DSM-IV or ICD-10 definitions^†); 3,181 ancestrally matched controls

Several sites: Bulgaria, England, Ireland, Portugal (Azores), Scotland and Sweden

High-density SNP microarrays

1.15× increase in schizophrenia for CNVs greater than 100 kb and in less than 5% of the sample. Deletions found in the VCSF region on chromosome 22, ad in chromosomes 15q13.3 and 1q21.1

Walsh et al. [20]

150 patients with schizophrenia; 268 ancestrally matched controls

USA (various locations)

CGH screen (85,000 probe arrays initially, and an Illumina 550 array for validation to identify microdeletions greater than 100 kb)

Novel deletions and duplications present in 15% of adult and 20% of COS patients versus 5% of controls. No one of these specifically associated with schizophrenia. In COS deletions in 2q31.2, 2p16.3 (NRXN1 gene), 16p11.2 were associated

Sutrala et al. [23]*

85 unrelated Caucasians with schizophrenia (DSM-IV definition); control DNA was from the CEPH^† collection

England and Ireland

CGH screen with oligonucleotide probes of 891 candidate genes, then allele quantification by DNA pooling for 15 genes

CGH screen yielded CNVs in six genes, but no excess in schizophrenia. No CNV was found by either method to be in excess in schizophrenia