Regulation of alpha7-nicotinic receptor subunit and alpha7-like gene expression in the prefrontal cortex of patients with bipolar disorder and schizophrenia.
OBJECTIVE
The alpha7-nicotinic receptor subunit gene (CHRNA7) is located at chromosome 15q13-14, a region previously linked with schizophrenia. Genetic association and mRNA expression studies also implicate CHRNA7 in schizophrenia. The CHRNA7 gene has a partial duplication that constitutes the alpha7-like nicotinic receptor gene (CHRFAM7A). We hypothesized that major psychoses could affect the expression of both CHRNA7 and CHRFAM7A.


METHODS
CHRNA7 and CHRFAM7A mRNA levels were measured in postmortem prefrontal cortex (donated by the Stanley Foundation) from subjects with schizophrenia, bipolar disorder and unaffected controls (n = 35 each).


RESULTS
The mRNA levels of alpha7 and alpha7-like genes have a positive correlation overall (r = 0.25; P = 0.009), however, there is no significant difference in the expression of CHRNA7 among the three diagnostic groups.


CONCLUSIONS
This correlation is driven by the bipolar group (r = 0.43; P = 0.009), and is absent in schizophrenia and unaffected controls, suggesting an alteration in the CHRNA7:CHRFAM7A ratio in bipolar disorder.
De Luca
V
V
Department of Psychiatry, Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada.
Likhodi
O
O
Van Tol
H H M
HH
Kennedy
J L
JL
Wong
A H C
AH
D000328:Adult; D001714:Bipolar Disorder / Q000235:genetics* / Q000473:pathology; D002884:Chromosomes, Human, Pair 15; D005260:Female; D020440:Gene Duplication; D015870:Gene Expression / Q000502:physiology*; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics; D011978:Receptors, Nicotinic / Q000235:genetics*; D012016:Reference Values; D012307:Risk Factors; D012559:Schizophrenia / Q000235:genetics* / Q000473:pathology; D013223:Statistics as Topic
C498540:CHRNA9 protein, human; D012333:RNA, Messenger; D011978:Receptors, Nicotinic