A NOVEL DELETION MUTATION OF KCNQ1 THAT CAUSES LONG QT SYNDROME IN A NEAR-DROWNING PATIENT'S FAMILY

Title:

A NOVEL DELETION MUTATION OF KCNQ1 THAT CAUSES LONG QT SYNDROME IN A NEAR-DROWNING PATIENT'S FAMILY
This work was supported by a Grand-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan.

DOI No:

10.1142/9789812702234_0076

Source:

ADVANCES IN ELECTROCARDIOLOGY 2004 (pp 283-286)

Author(s):

HARUYUKI YAMAZAKI
Department of Pediatrics, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan
KUNIO OHTA
Department of Pediatrics, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan
AKIKO ISHIZAKI
Department of Pediatrics, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan
NAMI NAKAMURA
Department of Pediatrics, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan
TAKEKATSU SAITO
Department of Pediatrics, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan
YO NIIDA
Department of Pediatrics, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan
SHOICHI KOIZUMI
Department of Pediatrics, Graduate School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan

Abstract:

Congenital long QT syndrome (LQTS), caused by mutations in ion-channel genes, KCNQ1 (LQT1), HERG (LQT2), or SCN5A (LQT3), is characterized by a prolonged QT interval on the electrocardiogram, syncope and fatal ventricular arrhythmias. Factors triggering cardiac events differ among the three distinct forms of LQTS. We have investigated mutations of these three genes in a near-drowning patient's family. The proband is a 9-year-old female. DNA sequencing confirmed the presence of a 3-bp (TCT) deletion within the transmembrane domain S5 in the LQT1 gene. This 3-bp deletion results in a novel in-frame deletion of a single amino acid (phenylalanine), delF275. The identical mutation was confirmed in her sister and father, both of whom had no history of syncope. This is consistent with the notion that swimming appears to be a gene-specific (KCNQ1) anythmogenic trigger for LQTS. Analysis of LQTS genes will provide useful information for selection of the careers at risk. It is still unknown, however, why the clinical phenotype may vary considerably, even among the careers of the same mutation. We need to accumulate further clinical and laboratory evidences to answer this question.

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