What question did this study set out to answer?

Determine the genetic cause and evaluate clinical variability of Romano-Ward long QT syndrome across five related families.

July 1, 1996Journal of Medical GeneticsOpen Access

Evidence of a long QT founder gene with varying phenotypic expression in South African families.

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Population

Five South African families of northern European descent with Romano-Ward long QT syndrome.

Design

Cohort

Authors

TJTertia De JagerUniversity of Utah CCClive CorbettPanorama Research (United States)JBJ. BadenhorstGroote Schuur Hospital

Discussion

Member takes

Implication

Supports targeted KVLQT1 screening in founder populations; leaves open mechanisms driving variable LQTS expressivity.

Key Points

Determine the genetic cause and evaluate clinical variability of Romano-Ward long QT syndrome across five related families.
Conducted genetic linkage analysis on chromosome 11p15.5 markers and constructed haplotypes across five multigenerational families of northern European descent.
Identified gene carriers by screening for the Ala212Val mutation in the KVLQT1 potassium channel gene and assessed electrocardiographic QTc intervals and clinical severity.
Linkage mapping and haplotype construction demonstrated a shared Ala212Val mutation in KVLQT1 on chromosome 11p15.5 across all five pedigrees, establishing a founder gene effect (maximum lod score 15.43 at D11S922).
Mean QTc intervals differed between pedigrees, measuring 0.48 s in carriers and 0.39 s in non-carriers in pedigree 161 versus 0.52 s in carriers and 0.42 s in non-carriers in pedigree 162.
Clinical symptoms varied substantially in severity between family lineages despite the presence of the identical founder mutation.

Structured PICO

Population

Five South African families of northern European descent (pedigrees 161, 162, 163, 164, and 166) with Romano-Ward long QT syndrome.

Comparator

Non-carriers within the same families

Outcome

Genetic linkage (lod scores), identification of the causal mutation, and QTc interval differences between carriers and non-carriers.surrogate

Identifies a founder Ala212Val mutation in the KVLQT1 gene responsible for Romano-Ward long QT syndrome in South African families, highlighting variable phenotypic expression.

Cite This Study

Jager et al. (1996) studied this question.

synapsesocial.com/papers/6a7089fd5d37378ac1dda6fe https://doi.org/10.1136/jmg.33.7.567

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Evidence of a long QT founder gene with varying phenotypic expression in South African families.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Evidence of a long QT founder gene with varying phenotypic expression in South African families.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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