Schizophrenia has long been known to be an illness with significant evidence for a genetic predisposition. The purpose of this study is to determine the genetic abnormalities that cause childhood and adult onset schizophrenia.
It is known from genetic linkage and gene expression studies that the alpha 7 nicotinic receptor gene is abnormally expressed in people with schizophrenia. The immediate objectives of this proposal support the long-term objectives of a comprehensive description of the pathophysiology of schizophrenia and new drug treatments by carefully defining the physiological genotype-phenotype relationship for a single candidate gene. Subjects and family members with a mental illness or who appear to have a mental illness will be asked to undergo an interview, perform some mental tests and have a blood, urine, and saliva sample taken one time.
Study Type
OBSERVATIONAL
Enrollment
538
Diagnostic evaluation for schizophrenia. Schizophrenia includes schizophrenia and schizoaffective disorder.
VA Eastern Colorado Health Care System, Denver
Denver, Colorado, United States
Genetic Linkage
Log of the Odds for Linkage, a standard genetic analysis metric. The number shown as a result is from a polymorphism in the promoter of the gene for the alpha7 nicotinic receptor on chromosome. Its presence in the individuals in this study, considering all three groups in one analysis, is compared to what of P50 sensory gating. P50 is a Positive wave in scalp-recorded auditory evoked potential that occurs 50 msec after the sound stimulus. P50 sensory gating is the decrement in this wave to the second of repeated sounds. The log of the odds is the common logarithm of the ratio of the odds that the gene polymorphism and P50 sensory gating are associated versus the odds that they are both distributed in the individuals at random. It is similar to the more common chi squared.
Time frame: ten years
Heritability Coefficient
h squared which ranges from 0 to 1. This number is similar to the more standard Pearson's correlation coefficient, except that the variable, in this case P50 sensory gating, is correlated across the statuses: schizophrenia proband (has the illness), schizophrenia relative (not ill but relative of someone who is), or control (not ill and has no known ill relative, P50 is a Positive wave in scalp-recorded auditory evoked potential that occurs 50 msec after the sound stimulus. P50 sensory gating is the decrement in this wave to the second of repeated sounds.
Time frame: 5 years
Log of the ODDS of Linkage
Log of the ODDS ratio of Linkage divided by the ODDS of no linkage from a maximum likelihood analysis conducted using the statistical program LINKAGE
Time frame: 1 day
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