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.
Bowen
T
T
Division of Psychological Medicine, University of Wales College of Medicine, Cardiff, UK.
Ashworth
L
L
Kirov
G
G
Guy
C A
CA
Jones
I R
IR
McCandless
F
F
Craddock
N
N
O'Donovan
M C
MC
Owen
M J
MJ
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