SCN5A Variant R1644C

Summary of observed carriers, functional annotations, and structural context for SCN5A R1644C. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT3 penetrance

27%

3/18 effective observations

Estimated BrS1 penetrance

37%

6/18 effective observations

Total carriers

8

5 BrS1 · 2 LQT3 · 1 unaffected

R1644C is present in 1 alleles in gnomAD. This residue resides in a Mild_Hotspot region for Brugada syndrome and a Mild_Hotspot region for LQT3.

Variant features alone are equivalent to phenotyping 1 individuals for Brugada syndrome and 1 individuals for LQT3.

In silico predictors

Variant-level computational predictors.
PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-7.27 1 -5.97 0.939 22 38

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. Penetrance density summarises neighbouring residue risk (Kroncke et al. 2019).

Reported carrier data

Observed carriers by publication or cohort.
Source Year Carriers Unaffected LQT3 BrS1 Other Other Disease
16344400 2005 1 0 1 0
16414944 2005 1 1 0 0
19411664 2009 3 0 3 0
24721456 2014 1 0 1 0
28341781 2017 1 0 1 0
19716085 2009 1 1 0 0
Literature, cohort, and gnomAD 8 1 2 5
Variant features alone 15 13 1 1

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

Functional data

Peak and late/persistent current values are relative to wild-type (100% indicates no change). V1/2 activation and inactivation denote the membrane potentials (mV) at which half-maximal current is achieved.

Published electrophysiology measurements.
PubMed ID Year Cell Type Peak Current (% WT) V1/2 Activation (mV) V1/2 Inactivation (mV) Late/Persistent Current (% WT)
16344400 2005 HEK 126 8.3 -1
16414944 2005
19411664 2009
24721456 2014
28341781 2017
19716085 2009

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 R1644C.
Neighbour residue Distance (Å) Observed variants
1643 7 I1643L,
1778 12
1653 15
1635 10
1652 12 M1652T, M1652R,
1634 8 L1634P,
1650 11 L1650F,
1641 6
1639 7 G1639A,
1779 13 T1779M,
1787 10 S1787N,
1654 15
1786 14 c.5356_5357delCT, L1786Q, L1786R,
1648 7
1649 10 A1649V,
1644 0 R1644C, R1644H, R1644L,
1640 7
256 12
1793 11 M1793K,
1781 14 E1781G, E1781D, E1781D,
1789 6
1632 15 R1632C, R1632H, R1632L,
255 13
1645 5 T1645M,
1796 13
1788 10 c.5361_5364delTGAG,
1638 6 R1638X, R1638Q,
1651 9
259 14
1633 11
1791 13
1637 5
253 13
1792 10 D1792N, D1792Y, D1792V,
1636 9
407 15
1775 13 F1775V, p.F1775LfsX15,
1642 7 G1642E,
1790 10 D1790N, D1790G, p.D1790del,
1631 13 G1631D,
252 12
1647 6
1822 14 c.5464_5467delTCTG, c.5464-5467delTCTG
1646 8
1782 12