J Korean Neuropsychiatr Assoc.  2001 Sep;40(5):955-964.

CAG Repeats of KCNN3 Gene in the Patients with Schizophrenia

• Kim DK
• Lim SW
• Koh HJ
• Seo MY
• Sohn SE
• Lee S
• Hwang HZ
• Jin DK
• Kim BL

Abstract

OBJECTS:We investigated a possible association between the polymorphic trinucleotide repeat(TNR) expansion in neuronal potassium channel gene KCNN3 and schizophrenia.
METHODS
CAG/CTG repeat distribution in KCNN3, CTG18.1 and ERDA1 was examined and the copy number of ligation product in repeat expansion detection(RED) was measured in Korean patients with schizophrenia(n=245) and ethnically matched healthy controls(n=116).
RESULTS
Longer alleles in the KCNN3 gene were over-represented in patients. The frequency of alleles with CAG repeats longer than 19 copy in the KCNN3 gene was higher in the patients with schizophrenia as compared to controls(73.3% vs. 65.1%;p=0.029, Fisher's exact test). And this difference was more prominent in schizophrenic patients with familial background(p=0.03, Fisher's exact test). We found no difference in the frequency of longer alleles between negative and positive subtypes of schizophrenia. Ligation product size in RED and alleles with CAG repeat number in the CTG18.1 gene was not increased in the patients. The copy number of ligation product in RED was highly correlated with CAG/CTG copies of ERDA1 in the patient group(r=0.45, p<0.001) as well as in the control group(r=0.44, p<0.001). However, CAG repeat length in the KCNN3 gene was not correlated with ERDA1 score.
CONCLUSIONS
Our results support the hypothesis that the longer allele of KCNN3 may be considered as a candidate gene for schizophrenia, especially in the case with familial background. And the RED assay results was affected by the CAG copy number of ERDA1.

Keyword

Schizophrenia; Trinucleotide repeat(TNR); Repeat expansion detection(RED); KCNN3; CTG18.1; ERDA1

MeSH Terms

Alleles
Humans
Ligation
Neurons
Potassium Channels
Schizophrenia*
Potassium Channels