White matter microstructural impairments and genetic liability to familial bipolar I disorder.
BACKGROUND
Subtle abnormalities in frontal white matter have been reported in bipolar disorder.


OBJECTIVE
To assess whether impaired integrity of white matter tracts is associated with bipolar disorder and genetic liability for the disorder.


METHODS
A total of 19 patients with psychotic bipolar I disorder from multiply affected families, 21 unaffected first-degree relatives and 18 comparison individuals (controls) underwent diffusion tensor imaging. Whole brain voxel-based analyses compared fractional anisotropy between patients and relatives with controls, and its relationship with a quantitative measure of genetic liability.


RESULTS
Patients had decreased fractional anisotropy compared with controls in the genu of the corpus callosum, right inferior longitudinal fasciculus and left superior longitudinal fasciculus. Increased genetic liability for bipolar disorder was associated with reduced fractional anisotropy across distributed regions of white matter in patients and their unaffected relatives.


CONCLUSIONS
Disturbed structural integrity within key intra- and interhemispheric tracts characterises both bipolar disorder and genetic liability for this illness.
Chaddock
Christopher A
CA
Department of Psychiatry, PO 63, Division of Psychological Medicine, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK. chris.chaddock@iop.kcl.ac.uk
Barker
Gareth J
GJ
Marshall
Nicolette
N
Schulze
Katja
K
Hall
Mei Hua
MH
Fern
Adele
A
Walshe
Muriel
M
Bramon
Elvira
E
Chitnis
Xavier A
XA
Murray
Robin
R
McDonald
Colm
C
D000328:Adult; D016880:Anisotropy; D001714:Bipolar Disorder / Q000235:genetics* / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010375:Pedigree