The promoter -194 C polymorphism of the nicotinic alpha 7 receptor gene has a protective effect against the P50 sensory gating deficit.
As suggested by several studies, abnormal sensory gating measured by the P50 paradigm could be an endophenotype predisposing to schizophrenia. In a previous work, we have shown a significant association between the presence of at least one -2 bp deletion located within exon 6 of the CHRNA7-like gene and the P50 abnormality in the general population. A recent study involved polymorphisms located in the core promoter region of the CHRNA7 gene as risk factors for the P50 inhibitory deficit. Screening for promoter variants in a large population of schizophrenic patients (n=111) and control subjects (85), for whom auditory-evoked potentials had been recorded did not allow us to replicate these results. By contrast, we showed a significant association between the -194 C allele and a T/C ratio <0.45, thus demonstrating a protective effect of this variant for the sensory gating deficit. Such conflicting results can be reconciled if we consider that the -194 C polymorphism has no causative effect, but is in linkage disequilibrium with other causal variations for the P50 sensory gating deficit, and that different alleles are in disequilibrium in different populations.
INSERM EMI 9906, IFRMP, Faculté de Médecine et de Pharmacie, Rouen, France.
E
E
Houy
G
G
Raux
F
F
Thibaut
A
A
Belmont
C
C
Demily
G
G
Allio
S
S
Haouzir
G
G
Fouldrin
M
M
Petit
T
T
Frebourg
D
D
Campion
D000328:Adult; D001483:Base Sequence; D017931:DNA Primers; D005072:Evoked Potentials, Auditory / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011978:Receptors, Nicotinic / Q000235:genetics*; D012559:Schizophrenia / Q000235:genetics*; D012678:Sensation Disorders / Q000235:genetics* / Q000517:prevention & control; D017384:Sequence Deletion; D064569:alpha7 Nicotinic Acetylcholine Receptor
C579167:Chrna7 protein, human; D017931:DNA Primers; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor