Two recent studies have shed light on how rare and common genetic causes of schizophrenia seem to often disrupt the same biological processes that end up resulting in schizophrenia. According to Nature, one study used genome-wide association studies, also known as GWASs, to look at the genomes of approximately 77,000 people diagnosed with schizophrenia and approximately 244,000 healthy people as a control. This study was able to identify over 300 common genetic variants that very slightly increases risk of schizophrenia. Understanding these factors helps to understand what regions of the genome are affected, but not what genes exactly are affected. However, being able to narrow down the region and processes affected still gives us a lot of new knowledge that can be further studied going forward.
While this first study looked at common risk factors that slightly increased risk, the second study looked for rare risk factors that significantly increased risk. This study examined the sequenced protein-coding parts of roughly 24,000 people with schizophrenia and roughly 97,000 healthy control's genomes. This studies data combined with that of the first study revealed 10 genes that were major contributors to schizophrenia. Looking further into these 10 genes found that 6 of them were also linked to developmental delay and intellectual disability, and 3 were found linked only to schizophrenia as they caused protein blocking. More studies are still being done to further understand the overlap between the developmental disorders and schizophrenia as well as the biological processes that are disrupted and cause schizophrenia.