KCNQ1 Variant L374H

Summary of observed carriers, functional annotations, and structural context for KCNQ1 L374H. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT1 penetrance

62%

10/17 effective observations

Total carriers

7

6 LQT1 · 1 unaffected

Functional studies

0

Publications with functional data

L374H is present in 1 alleles in gnomAD. This residue resides in a Hotspot region for LQT1.

Variant features alone are equivalent to phenotyping 4 individuals with LQT1 and 6 unaffected individuals.

In silico predictors

Variant-level computational predictors.
PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density LQT1 (%)
-6.59 1.0 -1 0.973 56

PROVEAN scores below -2 suggest deleterious impact. REVEL scores above 0.5–0.75 are often interpreted as likely pathogenic. PolyPhen-2 scores above 0.85 are typically pathogenic. BLAST-PSSM reflects evolutionary conservation; more negative values indicate rarer substitutions. Penetrance density summarises neighbouring residue risk (Kroncke et al. 2019).

Reported carrier data

Observed carriers by publication or cohort.
Source Year Carriers Unaffected LQT1 Other Disease
31899541 2020 6 None 6 None
23631430 2013 1 None None None
19716085 2009 1 None 1 None
Literature, cohort, and gnomAD 7 1 6
Variant features alone 15 6 4

Totals may differ from individual publications due to duplicate patients removed during curation.

Nearby variants

Neighbouring residues within 15 Ångström provide structural context. Variants listed in the right-most column have been observed clinically or in gnomAD.

Previously observed variants near L374H.
Neighbour residue Distance (Å) Observed variants
374 0 L374H, L374F,
373 5 S373P,
375 5
525 5 A525T, A525V,
371 5 A371T,
377 5
522 6 Y522S,
372 6
378 6 A378T,
529 6
370 6 A370V,
526 7 K526Q, K526E,
376 7
524 9 V524G,
528 9
523 9
369 10
530 10
380 10 R380S, R380S, R380G,
521 10
381 10 C381Y,
527 11
379 11 W379R, W379R, W379C, W379C, W379G
368 11
367 11 Q367H, Q367H,
532 12
533 12 R533W, R533Q,
519 13 R519H, R519C,
518 13 R518Q, R518G,
531 13
382 13
520 13 M520R,
383 14
534 15
517 15 I517T,