The first solid genetic map of borderline personality disorder

The largest genetic study of borderline personality disorder so far compared 12,339 people with BPD to 1,041,717 people without it. It found 11 regions of the genome linked to the disorder, with common variants accounting for about 17.3% of underlying risk.

Borderline personality disorder is common and serious, but it has lagged far behind depression and schizophrenia in genetic research, mostly because nobody had assembled enough cases. An international team pooled data from many cohorts to build the largest genome-wide association study of BPD to date: 12,339 people with the diagnosis and 1,041,717 people without it, all of European ancestry, plus a separate replication sample of 685 cases and 107,750 controls. Scanning millions of common DNA variants, they identified 11 independent stretches of the genome associated with BPD and 9 candidate risk genes. Common variants together explained about 17.3% of the underlying liability, and a polygenic score built from the results accounted for roughly 4.6% of variation in who had the diagnosis. The genetic signal overlapped most strongly with post-traumatic stress disorder, depression, ADHD, antisocial behavior, and measures of suicide and self-harm. In two biobanks, higher BPD polygenic scores also tracked with physical conditions including obstructive pulmonary disease and diabetes. Two honest limits: every participant was of European ancestry, so the results may not carry over to other populations, and 4.6% of variance is nowhere near enough to say anything about an individual person's risk. What the study does establish is that BPD is polygenic, like other psychiatric conditions, and shares a good deal of its genetic footing with them.