What is the clinical evidence from this study?

Study design: Observational. Population: Long QT syndrome (LQTS). Intervention: KVLQT1 gene mutation (D188N) vs. Nonaffected individuals. Primary outcome: Mean QTc interval (p=<0.001).

What question did this study set out to answer?

To identify genetic mutations in the cardiac potassium channel gene KVLQT1 among individuals with long QT syndrome and evaluate phenotypic expression across an extended pedigree.

January 1, 1998Human Mutation

Molecular genetics of the long QT syndrome: Two novel mutations of the KVLQT1 gene and phenotypic expression of the mutant gene in a large kindred

Q: What are the key findings of this study?

Carriers of the D188N mutation in the KVLQT1 gene had a significantly longer mean QTc interval than nonaffected individuals (484 vs 406 ms, P<0.001).

Q: What question did this study set out to answer?

To identify genetic mutations in the cardiac potassium channel gene KVLQT1 among individuals with long QT syndrome and evaluate phenotypic expression across an extended pedigree.

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Key result

Carriers of the D188N mutation in the KVLQT1 gene had a significantly longer mean QTc interval than nonaffected individuals (484 vs 406 ms, P<0.001).

Key Points

To identify genetic mutations in the cardiac potassium channel gene KVLQT1 among individuals with long QT syndrome and evaluate phenotypic expression across an extended pedigree.
Screened 44 unrelated probands for mutations in the KVLQT1 gene using single-strand conformational polymorphism (SSCP) analysis followed by DNA sequencing.
Assessed genotype-phenotype cosegregation and measured QTc intervals in a large pedigree carrying the D188N mutation (30 affected and 43 nonaffected individuals).
Identified two novel mutations (T182I and D188N) in the pore-S6 domain that cosegregated with the disease in separate families, with no mutations detected at codon 212.
Mean QTc intervals were significantly longer in affected carriers compared to nonaffected family members (484 ± 38 ms vs. 406 ± 27 ms, P < 0.001), though individual values showed notable overlap.
QTc interval durations did not differ significantly between symptomatic and asymptomatic carriers of the D188N mutation.

Study Design

Type

Observational

Structured PICO

Population

44 unrelated probands with long QT syndrome and 73 individuals from a large pedigree (30 affected, 43 nonaffected) analyzed for KVLQT1 gene mutations.

Exposure

Genetic screening for KVLQT1 mutations using single-strand conformational polymorphism (SSCP) and DNA sequencing

Comparator

Nonaffected individuals within the pedigree (for phenotypic expression analysis)

Outcome

Identification of KVLQT1 gene mutations and phenotypic expression (QTc interval)surrogate

Main Result

Absolute Event Rate: 484% vs 406%

p-value: p=<0.001

The identification of two novel KVLQT1 mutations supports the functional significance of the pore-S6 domain and highlights the diagnostic utility of genetic testing in families with long QT syndrome.

Discussion

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Implication

D188N carriers may warrant closer LQTS surveillance; supports KVLQT1 testing in families but remains hypothesis-generating.

Cite This Study

Saarinen et al. (1998) conducted an observational in Long QT syndrome (LQTS). KVLQT1 gene mutation (D188N) vs. Nonaffected individuals was evaluated on Mean QTc interval (p=<0.001). Carriers of the D188N mutation in the KVLQT1 gene had a significantly longer mean QTc interval than nonaffected individuals (484 vs 406 ms, P<0.001).

synapsesocial.com/papers/6a94df89d44cea3cdd8279b6 https://doi.org/10.1002/(sici)1098-1004(1998)11:2<158::aid-humu9>3.3.co;2-3

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Molecular genetics of the long QT syndrome: Two novel mutations of the KVLQT1 gene and phenotypic expression of the mutant gene in a large kindred

Key Points

Study Design

Structured PICO

Main Result

Discussion

Implication

Cite This Study

Molecular genetics of the long QT syndrome: Two novel mutations of the KVLQT1 gene and phenotypic expression of the mutant gene in a large kindred

Key Points

Study Design

Structured PICO

Main Result

Discussion

Implication

Cite This Study

Also Consider

Also Consider