In the latest online edition of Nature Genetics, researchers at powerhouse genetics center Cold Springs Harbor Laboratory report that they have identified an important mutation that, while rare, significantly increases a person’s risk of developing schizophrenia. (If the Nature Genetics looks like only so much jargon, you can find a more readable overview here instead.)

In schizophrenia genetics, it’s becoming increasingly clear that numbers matter.

This recently-identified mutation comes in the form of a copy number variant — a place on the genome where the number of bases or genes differs from one individual to another. This latest schizophrenia-related mutation sits on chromosome 16, and people who have an extra copy of the relevant region of that chromosome appear to be almost 15 times more likely to develop schizophrenia, according to the study. The study augments previous work on the role of copy number variants in this condition.

In our book, we talk about genetics and a number of different mental health and developmental conditions in Chaper 7, and provide some background on copy number variants in Chapter 9.