Table 4.
Summary of population screening studies of long QT syndrome
| Splawskiet al. 2000 | Tester et al. 2005 Tester et al. 2005a | Napolitano et al. 2005 | Berge et al. 2008 | Kapplinger et al. 2009 | This study | ||
|---|---|---|---|---|---|---|---|
| Number of unrelated index cases (n) |
|
262 |
541 |
430 |
169 |
2500 |
200 |
| Detection rate (%) All cases/more stringent criteria (*Schwartz score ≥ 4) |
|
51 |
50/72* |
72 |
32/71 |
36 |
52 |
| Novel mutations (%) |
|
60 |
59 |
59 |
54 |
60 |
28 |
| Multiple mutations (%) |
|
- |
10 |
5 |
0 |
9 |
4 |
| Mutated gene: |
KCNQ1 (%) |
39 |
42 |
49 |
43 |
43 |
58 |
| |
KCNH2 (%) |
51 |
42 |
39 |
46 |
32 |
24 |
| |
SCN5A (%) |
6 |
15 |
10 |
9 |
13 |
13 |
| |
KCNE1 (%) |
2 |
0.5 |
2 |
2 |
3 |
1 |
| |
KCNE2 (%) |
2 |
0.5 |
1 |
- |
1 |
1 |
| |
RYR2 (%) |
- |
- 269/6a |
- |
- 41/17 |
- |
3 36/8 |
|
RYR2 (n/%) | |||||||
| Mutation type: |
Missense (%) |
72 |
73 |
72 |
65 |
70 |
70 |
| |
Nonsense (%) |
6 |
6 |
5 |
14 |
6 |
8 |
| |
In-frame ins/del (%) |
5 |
2 |
14 |
3 |
3 |
5 |
| |
Frame shift (%) |
10 |
12 |
6 |
13 |
15 |
12.5 |
| |
Splice site (%) |
7 |
6 |
3 |
5 |
6 |
1.5 |
| |
Large ins/del (%) |
- |
- |
- |
- |
- |
3 |
| Mutation region: |
N-terminal (%) |
22 |
16 |
8 |
22 |
8 |
25 |
| |
Transmembrane (%) |
54 |
49 |
64 |
54 |
57 |
47 |
| C-terminal (%) | 24 | 35 | 28 | 24 | 35 | 28 |