No evidence of association from transmission disequilibrium analysis of the hKCa3 gene in bipolar disorder.
OBJECTIVE
A recent case control study has suggested that modest enlargements of a highly polymorphic CAG repeat in exon 1 of the gene encoding potassium channel hKCa3 may be associated with bipolar disorder (BPD). We have examined this hypothesis by genotyping this locus in a family-based association study.


METHODS
One hundred and twenty-eight parent offspring trios of British Caucasian origin were examined where the proband was diagnosed with the American Psychiatric Association's Diagnostic and Statistical Manual (DSM)-IV BPD I (n = 123) or II (n = 5). An improved assay was used, with redesigned polymerase chain reaction (PCR) primers, permitting quicker and higher resolution genotyping. The resultant genotypes were analysed using the extended transmission/ disequilibrium test (ETDT).


RESULTS
The experimental data did not provide evidence for the preferential transmission of large alleles to bipolar cases (chi2 = 11.12, df = 10, p = 0.349).


CONCLUSIONS
Our data provide no support for the hypothesis that variation at the hKCa3 gene contributes to susceptibility to BPD.
Division of Psychological Medicine, University of Wales College of Medicine, Cardiff, UK.
T
T
Bowen
L
L
Ashworth
G
G
Kirov
C A
CA
Guy
I R
IR
Jones
F
F
McCandless
N
N
Craddock
M C
MC
O'Donovan
M J
MJ
Owen
D000328:Adult; D000368:Aged; D000483:Alleles; D001714:Bipolar Disorder / Q000235:genetics*; D016009:Chi-Square Distribution; D005260:Female; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010290:Parents; D011110:Polymorphism, Genetic; D015221:Potassium Channels / Q000235:genetics*; D024681:Potassium Channels, Calcium-Activated; D051640:Small-Conductance Calcium-Activated Potassium Channels; D019680:Trinucleotide Repeat Expansion / Q000235:genetics*
C406328:KCNN3 protein, human; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D051640:Small-Conductance Calcium-Activated Potassium Channels