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A potassium channel mutation in neonatal human epilepsy
C Biervert1, B C Schroeder, C Kubisch
1Institute for Human Genetics, University of Bonn, Bonn, Germany.
Science (New York, N.Y.)
|February 7, 1998
Summary
Benign familial neonatal convulsions (BFNC) is linked to a potassium channel gene (KCNQ2). Mutations in this gene impair potassium currents, causing this infant epilepsy syndrome.
Area of Science:
- Genetics
- Neuroscience
- Molecular Biology
Background:
- Benign familial neonatal convulsions (BFNC) is an inherited epilepsy affecting infants.
- Genetic loci for BFNC have been identified on chromosomes 20q13.3 and 8q24.
Purpose of the Study:
- To identify the gene responsible for BFNC.
- To understand the molecular mechanism underlying BFNC.
Main Methods:
- Positional cloning to isolate genes at the BFNC locus.
- Gene expression studies in Xenopus laevis oocytes.
- Analysis of KCNQ2 gene mutations in BFNC patients.
Main Results:
- The potassium channel gene KCNQ2, located on chromosome 20q13.3, was identified and found to be expressed in the brain.
- KCNQ2 expression in oocytes produced slow-activating potassium currents.
- A five-base pair insertion mutation in KCNQ2 was identified in a BFNC family, leading to a truncated protein lacking measurable current.
Conclusions:
- KCNQ2 mutations impair potassium-dependent repolarization.
- This impairment is the likely cause of benign familial neonatal convulsions.