Table 1.
Phenotypic Characteristics by Source of Subjects, Location of Mutation, Type of Mutation, and Topology of Mutation
| Source of Subjects | Location of Mutation | Type of Mutation | Topology of Mutation | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Characteristics | Rochester | Netherlands | Japan | Mayo | Transmembrane (S1-S4) | Transmembrane (S5- loop -S6) | N-Terminus | C-Terminus | Missense | Frameshift/nonsense | Others | α-helices | β-sheet | Neither |
| # unique mutations | 14 | 52 | 46 | 50 | 100 | 58 | 4 | 66 | 17 | 79 | ||||
| # of Patients | 456 | 214 | 95 | 93 | 44 | 259 | 243 | 312 | 555 | 261 | 42 | 319 | 141 | 398 |
| Female, % | 57 | 59 | 66 | 57 | 57 | 59 | 56 | 60 | 60 | 56 | 55 | 57 | 55 | 61 |
| ECG at enrollment | ||||||||||||||
| Age†‡§, yr | 25±20 | 33±21 | 30±18 | 22±16 | 28±16 | 24±19 | 32±21 | 26±19 | 28±20 | 27±19 | 26±22 | 25±19 | 31±22 | 28±19 |
| QTc†‡¶§, sec | 0.49±0.06 | 0.47±0.05 | 0.49±0.05 | 0.47±0.05 | 0.48±0.05 | 0.50±0.06 | 0.47±0.06 | 0.48±0.05 | 0.49±0.06 | 0.47±0.05 | 0.47±0.06 | 0.49±0.05 | 0.48±0.05 | 0.48±0.06 |
| QTp†‡, sec | 0.34±0.07 | 0.33±0.05 | 0.38±0.06 | 0.34±0.06 | 0.37±0.07 | 0.36±0.07 | 0.34±0.06 | 0.34±0.07 | 0.35±0.07 | 0.34±0.06 | 0.34±0.08 | 0.35±0.07 | 0.33±0.07 | 0.34±0.06 |
| Therapy, % | ||||||||||||||
| β-blockers | 51 | 45 | 45 | 60 | 48 | 53 | 45 | 51 | 49 | 51 | 50 | 51 | 48 | 49 |
| Pacemaker† | 6.8 | 0.5 | 1.1 | 0 | 2.3 | 6.6 | 2.5 | 2.9 | 4.5 | 2.7 | 2.4 | 5.6 | 2.8 | 2.8 |
| Sympathectomy | 2 | 0.9 | 0 | 1.1 | 2.3 | 1.5 | 0 | 2.2 | 1.6 | 0.8 | 2.4 | 1.6 | 2.8 | 0.8 |
| Defibrillator† | 14 | 4.7 | 6.3 | 25 | 18 | 14 | 8.2 | 12 | 11 | 13 | 17 | 12 | 9.9 | 13 |
| 1st Cardiac | 50 | 34 | 52 | 31 | 34 | 58 | 40 | 38 | 45 | 44 | 29 | 54 | 30 | 41 |
| Event*†‡§, % | ||||||||||||||
| Syncope†‡§ | 42 | 31 | 52 | 28 | 32 | 49 | 36 | 34 | 39 | 39 | 29 | 45 | 26 | 38 |
| Aborted Cardiac Arrest | 0.7 | 1.9 | 0 | 3.2 | 2.3 | 1.2 | 1.2 | 1 | 1.3 | 1.1 | 0 | 1.6 | 0.7 | 1 |
| Death†‡§ | 7.7 | 0.5 | 0 | 0 | 0 | 7.7 | 2.9 | 2.9 | 5.0 | 3.1 | 0 | 7.2 | 2.8 | 2.3 |
| Ever Cardiac Event, % | ||||||||||||||
| Syncope†‡§ | 42 | 31 | 55 | 28 | 32 | 49 | 36 | 34 | 39 | 39 | 29 | 45 | 26 | 38 |
| Aborted Cardiac Arrest† | 4.6 | 7.5 | 16 | 7.5 | 11 | 6.9 | 6.2 | 6.7 | 6.1 | 8.4 | 7.1 | 7.8 | 4.3 | 7 |
| Death†‡¶§ | 18 | 3.3 | 0 | 2.2 | 4.5 | 17 | 11 | 6.7 | 14 | 5.7 | 7.1 | 16 | 8.5 | 7.8 |
Plus-minus values are means ±SD. Percentages greater than 10 are rounded to a whole number.
The 858 subjects in this table include 60 subjects from the Rochester-based registry who died suddenly at a young age, were from families with known KCNH2 mutation, and were assumed to have the family mutation. QTp, corrected Q-Tpeak interval.
First cardiac event was syncope, aborted cardiac arrest, or sudden death, whichever occurred first.
P<0.01 for the comparison of characteristics among the four sources of subjects.
P<0.01 for the comparison of characteristics among the four locations of the mutations.
P<0.01 for the comparison of characteristics among the three major type of mutations.
P<0.01 for the comparison of characteristics among the three major topology of mutations.