Study Report

Reference	Serretti, A.,2001(a) PMID: 11472792
Citation	Serretti, A., R. Lilli, et al. (2001). "Tryptophan hydroxylase gene and major psychoses." Psychiatry Res 103(1): 79-86.
Disease Type	Bipolar Disorder & Schizophrenia & Major Depressive Disorder
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	inpatients affected by bipolar(n=627), major depressive (n=511), schizophrenic (n =210), and 380 controls
SNP/Region/Marker Size	1 variant
Predominant Ethnicity	Caucasian
Population	Italian
Age Group	Adults

Sample Diagnosis	DSM
Sample Status	One thousand four-hundred and twenty-four psychiatric inpatients (consecutively admitted to the Department of Neuropsychiatry at the Institute H. San Raffaele (DSNP-HSR., were included in this study.) Patients were collected for the European Collaborative Project on Affective Disorders(Souery et al., 1998. A sub-sample of 963 patients was evaluated using the Operational Criteria for Psychotic Illness Checklist OPCRIT (McGuffin et al., 1991) The presence of concomitant diagnoses of mental retardation or drug dependence, together with somatic or neurological illnesses that impaired psychiatric evaluation, represented exclusion criteria.Three-hundred and eighty control subjects were recruited among both healthy department personnel and people attending the general lab of our hospital (age:46.46,SD=13.67, males 50.2%) Before blood samples were drawn, controls were closely investigated to determine whether they or their first-degree relatives had psychiatric disturbances or previous psychiatric treatment, through interviews with subjects and relatives when possible.Only unaffected subjects with negative family histories were included in the study.
Technique	PCR and RFLP
Statistical Method	chi-square tests
Result Summary	TPH variants were not associated with major psychoses, but a trend was observed toward an excess of TPH*A/A in bipolar disorder. The analysis of symptomatology factors did not show any significant difference either; however, a trend was observed for males with the TPH*A genotype to have lower depressive symptoms compared with TPH*C subjects. Possible stratification factors such as current age and age of onset did not affect the observed results. TPH A218C variants are not, therefore, a major liability factor for the symptoms of major psychoses to have in the present sample. TPH*A containing variants may be a protective factor for depressive symptoms among male subjects with mood disorders or for a subtype of mood disorders characterized by a mainly manic form of symptomatology.