Familial leukoencephalopathy in bipolar disorder

Objective: Imaging studies of patients with bipolar disorder demonstrate changes in deep white matter and subcortical gray nuclei that are seen as focal hyperintensities on T₂-weighted magnetic resonance imaging (MRI). The objective of this study was to examine MRIs in a family with a strong history of bipolar disorder to look for possible MRI abnormalities in members with and without affective illness. Method: The authors obtained MRIs of 21 members of a family with a strong history of bipolar disorder. Eight of the family members studied had bipolar illness, one had symptoms of bipolar disorder but did not meet full DSM-III-R criteria, two had unipolar disorder, and 10 did not have bipolar disorder. Results: Fifteen of the 21 family members had MRI findings, including six of 10 family members who had no affective disorder and all of those with bipolar disorder. Lesions of both white matter and subcortical gray nuclei were found. Conclusions: Although the clinical significance of these MRI findings is unknown, the high prevalence of MRI findings in both affected and unaffected family members suggests that MRI findings may potentially serve as a biological marker for bipolar disorder. Recent genetic studies have established a link between familial leukoencephalopathy and chromosome 19. If leukoencephalopathy appears to be related to bipolar disorder, it may allow clearer characterization of the genetics of the disorder.