Ring chromosome 22 and mood disorders.

The case of a 21-year-old man with severe developmental disabilities, ring chromosome 22 and rapid-cycling bipolar illness is presented. This is the first reported occurrence of mood disorder in a person with ring chromosome 22. Previously published case reports describing behavioural problems associated with this chromosome disorder suggest that severe hyperactivity is typical and that affected individuals may have an excited mood state. These symptoms are consistent with atypical bipolar disorder and raise the possibility that ring chromosome 22 increases the risk for atypical bipolar disorder.