Bipolar Genetics Studies

Studies have shown us that depression and bipolar disorder tend to run in families.  First-degree relatives of bipolar patients (their parents, siblings, and children) are at a 10-fold increased risk for bipolar disorder and are also at increased risk for depression.  However, because family studies cannot tease apart genetic susceptibility and environmental susceptibility, both of which may be shared within a family, twin studies have provided us with additional insight.  Monozygotic (identical) twins, who share 100% of their genetic information (DNA), are more likely to both have a mood disorder than dizygotic (fraternal) twins, who share, on average, 50% of their genetic information.  This difference is evidence for a genetic susceptibility for bipolar disorder.  The proportion of the liability to bipolar disorder that is thought to be genetic about 75%.

At Johns Hopkins, we are actively searching for susceptibility genes for bipolar disorder.  Finding the genes responsible for bipolar disorder will help us to understand what goes wrong in the brain and should yield better treatments, better diagnoses, and techniques for illness prevention.

No.  All interviews can be conducted by telephone, and we have interview times available throughout the day and evening to accommodate different time zones.  We mail kits with blood tubes and shipping materials so participants can have their blood drawn at their doctor’s office or at a local lab and mail the blood to a storage facility at Rutgers University in New Jersey.

All of your identifying information will be kept in a locked filing cabinet or in a secure database.  Your blood, which will be shipped to our facility at Rutgers University in New Jersey, will only be labeled with your numerical study identification, not your name.  Our research is collaborative, meaning that researchers at other universities will have access to your clinical and genetic information, but all of this information will be de-identified and anonymous.

Psychiatrists at Johns Hopkins have been looking for the genes for bipolar disorder since 1988. Highlights of our research findings to date include:

• The systematic study of the distribution and genetic salience of bipolar II disorder.
• The identification of two regions that likely harbor bipolar disorder genes on chromosomes 8 and 18.
• The finding that inheritance of bipolar disorder susceptibility may include a parent-of-origin effect (may differ depending on whether transmission comes from fathers or from mothers).
• The demonstration of familial clustering of psychotic bipolar disorder and localization of genes for this subtype of illness to two regions of chromosomes 13 and 22.
• The demonstration of familial clustering of early-onset bipolar disorder and localization of a gene for this form of illness to a region of chromosome 21.
• A role in the identification of the two strongest candidate genes for bipolar disorder, BDNF (brain-derived neurotrophic factor) and DAOA (d-amino acid oxidase activator).