Duplications of a given DNA sequence on chromosome 16 are associated with schizophrenia, according to a study published online in this week's Nature Genetics. Deletions and duplications of this same DNA sequence on the chromosome have previously been associated with autism spectrum disorders.
Schizophrenia is a serious mental disorder that affects approximately 24 million people worldwide and is characterized by an altered sense of reality. Common symptoms include hallucinations, delusions, and disorganized speech and cognitive processing.
Jonathan Sebat and colleagues analyzed a distinct region on chromosome 16 in nearly 2000 individuals with schizophrenia and found that small duplications in this region were found in 0.63% of cases, compared to in only 0.03% of nearly 4000 individuals without schizophrenia. The duplication at this region includes 28 genes, many of which have potential roles in neurodevelopment, and is associated with a 14.5-fold increase in risk of schizophrenia.
An integrated analysis of the scientists' data with four publicly available datasets found that this duplication is associated with schizophrenia and bipolar disorder, while the reciprocal deletions are more specifically associated with autism spectrum disorders.