Phenotypic variation between parent-offspring trios and non-trios in genetic studies of schizophrenia.
BACKGROUND
Phenotypic differences between parent-offspring trios and non-trios have been reported for various psychiatric disorders, and it has been suggested that this may make comparisons of case-control and family-based results for gene-disease association studies inappropriate.


OBJECTIVE
To compare phenotypes between trios and non-trios with schizophrenia, and explore possible reasons for differences observed.


METHODS
Phenotypes were compared between trios (n=75) and non-trios (n=424) collected as part of a case-control study.


RESULTS
Differences were observed for most phenotypes investigated, although all were eliminated after adjusting for confounding.


CONCLUSIONS
Confounding, genetic heterogeneity or selection bias could result in differences in case-control and family-based results. However as we discuss, where adequately designed case-control studies are used, gene-disease association results would be incomparable between family-based and case-control studies only if genetic heterogeneity was present. These results do not support the presence of such genetic heterogeneity in schizophrenia.
Zammit
Stanley
S
Department of Psychological Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK. zammits@cardiff.ac.uk
Lewis
Glyn
G
Thapar
Anita
A
Owen
Richard
R
Jones
Gaynor
G
Jones
Susan
S
Sanders
Rob
R
Milham
Charis
C
Mahdi
Ameera
A
O'Donovan
Michael C
MC
Owen
Michael J
MJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics*