Novel donor splice site mutation in the KVLQT1 gene is associated with long QT syndrome

TY - JOUR

T1 - Novel donor splice site mutation in the KVLQT1 gene is associated with long QT syndrome

AU - Kanters, Jørgen K.

AU - Larsen, Lars Allan

AU - Orholm, Marianne

AU - Agner, Erik

AU - Andersen, Paal Skytt

AU - Vuust, Jens

AU - Christiansen, Michael

PY - 1998/1/1

Y1 - 1998/1/1

N2 - Introduction: Inherited long QT syndrome (LQTS) recently has been associated with mutations in genes coding for potassium (KVLQT1, KCNE1, and HERG) or sodium (SCN5A) ion channels involved in regulating either sodium inward or potassium outward currents of heart cells, resulting in prolongation of the repolarization period. We describe a new mutation, a -1 donor splice site mutation in a kindred with two affected members (QTc = 0.61 and 0.54 sec). Methods and Results: Single stranded conformation polymorphism (SSCP) analyses were performed on DNA fragments amplified by polymerase chain reaction from DNA extracted from whole blood. Aberrant conformers were analyzed by DNA sequencing. SSCP analysis of the KVLQT1 gene revealed an aberrant conformer in the affected family members. DNA sequencing confirmed the presence of a G→A change in the last nucleotide of codon 344. This mutation does not cause an amino acid change, but a change of the splice site characteristics at the 3' end of exon 6. The mutation may affect, through deficient splicing, the putative sixth transmembrane segment of the K+ channel, and this type of mutation has not previously been described in KVLQT1. Conclusion: The clinical course of LQTS in the affected family members, in whom no deaths occurred despite 20 to 30 syncopes, can be explained by the ability of the cellular machinery to perform partial correct splicing in the mutant allele. This type of mutation may be misinterpreted as a normal variant, since it is a point mutation causing neither an amino acid change nor the introduction of a stop codon.

AB - Introduction: Inherited long QT syndrome (LQTS) recently has been associated with mutations in genes coding for potassium (KVLQT1, KCNE1, and HERG) or sodium (SCN5A) ion channels involved in regulating either sodium inward or potassium outward currents of heart cells, resulting in prolongation of the repolarization period. We describe a new mutation, a -1 donor splice site mutation in a kindred with two affected members (QTc = 0.61 and 0.54 sec). Methods and Results: Single stranded conformation polymorphism (SSCP) analyses were performed on DNA fragments amplified by polymerase chain reaction from DNA extracted from whole blood. Aberrant conformers were analyzed by DNA sequencing. SSCP analysis of the KVLQT1 gene revealed an aberrant conformer in the affected family members. DNA sequencing confirmed the presence of a G→A change in the last nucleotide of codon 344. This mutation does not cause an amino acid change, but a change of the splice site characteristics at the 3' end of exon 6. The mutation may affect, through deficient splicing, the putative sixth transmembrane segment of the K+ channel, and this type of mutation has not previously been described in KVLQT1. Conclusion: The clinical course of LQTS in the affected family members, in whom no deaths occurred despite 20 to 30 syncopes, can be explained by the ability of the cellular machinery to perform partial correct splicing in the mutant allele. This type of mutation may be misinterpreted as a normal variant, since it is a point mutation causing neither an amino acid change nor the introduction of a stop codon.

KW - -1 donor splice site mutation

KW - KCNA9

KW - KVLQT1

KW - Long QT syndrome

UR - http://www.scopus.com/inward/record.url?scp=0031813504&partnerID=8YFLogxK

U2 - 10.1111/j.1540-8167.1998.tb00944.x

DO - 10.1111/j.1540-8167.1998.tb00944.x

M3 - Journal article

C2 - 9654228

AN - SCOPUS:0031813504

SN - 1045-3873

VL - 9

SP - 620

EP - 624

JO - Journal of Cardiovascular Electrophysiology

JF - Journal of Cardiovascular Electrophysiology

IS - 6

ER -