Phenotypes associated with the disease long QT syndrome 2 (OMIM:613688):
- Ventricular fibrillation (HP:0001663): Uncontrolled contractions of muscles fibers in the left ventricle not producing contraction of the left ventricle. Ventricular fibrillation usually begins with a ventricular premature contraction and a short run of rapid ventricular tachycardia degenerating into uncoordinating ventricular fibrillations. Evidence: TAS. (OMIM:613688)
- Early young adult onset (HP:0025708): Onset of disease at an age of greater than or equal to 16 to under 19 years. Evidence: PCS. Frequency: 1/1. (PMID:34502138)
- Cardiac arrest (HP:0001695): An abrupt loss of heart function. Evidence: PCS. Frequency: 1/4. (PMID:34357002)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 1/4. (PMID:34357002)
- Adult onset (HP:0003581): Onset of disease manifestations in adulthood, defined here as at the age of 16 years or later. Evidence: PCS. Frequency: 4/5. (PMID:34901807;PMID:34357002)
- Prolonged QT interval (HP:0001657): Increased time between the start of the Q wave and the end of the T wave as measured by the electrocardiogram (EKG). Evidence: PCS. Frequency: 4/4. (PMID:34357002)
- Prolonged QTc interval (HP:0005184): A longer than normal interval (corrected for heart rate) between the Q and T waves in the heart's cycle. Prolonged QTc can cause premature action potentials during late phase depolarizations thereby leading to ventricular arrhythmias and ventricular fibrillations. Evidence: PCS. Frequency: 1/1. (PMID:34901807)
- Notched T wave (HP:0034303): A bifid T-wave with a notch duration between the 2 peaks at least 0.04 sec and an amplitude at least 0.05 mV. Evidence: PCS. Frequency: 3/3. (PMID:34357002)
- Torsade de pointes (HP:0001664): A type of ventricular tachycardia characterized by polymorphioc QRS complexes that change in amplitue and cycle length, and thus have the appearance of oscillating around the baseline in the EKG. Evidence: TAS. (OMIM:613688)
- Syncope (HP:0001279): A transient loss of consciousness (i.e., characterized by a rapid onset, a short duration, and a spontaneous and complete recovery) due to cerebral hypoperfusion. Evidence: PCS. Frequency: 3/4. (PMID:34357002)
- Sudden cardiac death (HP:0001645): The heart suddenly and unexpectedly stops beating resulting in death within a short time period (generally within 1 h of symptom onset). Evidence: PCS. Frequency: 2/5. (PMID:34502138;PMID:34357002)
- Autosomal dominant inheritance (HP:0000006): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:7889573)