Table. Demographic and Clinical Characteristics of Patients Confirmed to Have LOF and GOF Variants In Vitro.
| Characteristic | Patient groupa | |||
|---|---|---|---|---|
| LOF variant (n = 19) | GOF variant (n = 4) | |||
| Probands (n = 6) | Relatives (n = 13) | Probands (n = 3) | Relatives (n = 1) | |
| Age, median (IQR), y | 22 (8-34) | 20 (10-53) | 11 | 14 |
| Sex | ||||
| Male | 1 (17) | 6 (46) | 3 (100) | 1 (100) |
| Female | 5 (83) | 7 (54) | 0 | 0 |
| Arrhythmic event(s) at diagnosis | 6 (100) | 3 (23) | 3 (100) | 1 (100) |
| Exertion/emotion trigger | 3 (50) | 0 | 3 (100) | 1 (100) |
| No trigger | 2 (33) | 3 (100) | 0 | 0 |
| Unknown trigger | 1 (17) | 0 | 0 | 0 |
| Exercise stress testing performed | 4 (67) | 11 (84) | 3 (100) | 1 (100) |
| Normal | 3 (75) | 7 (64) | 0 | 1 (100) |
| PVCs only | 0 | 4 (36) | 3 (100) | 0 |
| Monomorphic couplet | 1 (25) | 0 | 0 | 0 |
| β-Blocker treatmentb | 4 (100) | 12 (92) | 3 (100) | 1 (100) |
| ICD implantb | 3 (50) | 1 (8) | 3 (100) | 1 (100) |
| Atrial arrhythmias | 3 (50) | 0 | 1 (33) | 0 |
| Deceased | 3 (50) | 0 | 0 | 0 |
Abbreviations: GOF, gain-of-function; ICD, implantable cardioverter-defibrillator; LOF, loss-of-function; PVC, premature ventricular complex.
a
Unless otherwise indicated, data are expressed as number (%) of patients. Note that 1 of the 24 patients (4%) is not included because the variant was wild-type–like during caffeine stimulation (proband 10, with the RyR2-p.I4867T variant). No patient with an LOF variant had abnormal cardiac imaging at presentation, but 2 had minimally abnormal electrocardiograms (nonspecific ST/T wave changes and incomplete right bundle branch block with poor R wave progression).
b
Excludes patients with sudden unexpected death at presentation.