- Juvenile onset (HP:0003621): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: PCS. Frequency: 3/3. (PMID:12021217)
- 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:608751)
- Cardiac arrest (HP:0001695): An abrupt loss of heart function. Evidence: TAS. (OMIM:608751)
- T-wave inversion (HP:0010872): An inversion of the T-wave (which is normally positive). Evidence: PCS. Frequency: 1/1. (PMID:12021217)
- Reduced left ventricular ejection fraction (HP:0012664): A diminution of the volumetric fraction of blood pumped out of the ventricle with each cardiac cycle. Evidence: PCS. Frequency: 0/1. (PMID:12021217)
- Hypertrophic cardiomyopathy (HP:0001639): Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality. Evidence: PCS. Frequency: 13/13. (PMID:8673105)
- Left atrial enlargement (HP:0031295): Increase in size of the left atrium. Evidence: PCS. Frequency: 1/2. (PMID:12021217)
- Autosomal recessive inheritance (HP:0000007): 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 individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:12021217)
- Restrictive cardiomyopathy (HP:0001723): Restrictive left ventricular physiology is characterized by a pattern of ventricular filling in which increased stiffness of the myocardium causes ventricular pressure to rise precipitously with only small increases in volume, defined as restrictive ventricular physiology in the presence of normal or reduced diastolic volumes (of one or both ventricles), normal or reduced systolic volumes, and normal ventricular wall thickness. Evidence: PCS. (PMID:12021217)
- Congestive heart failure (HP:0001635): The presence of an abnormality of cardiac function that is responsible for the failure of the heart to pump blood at a rate that is commensurate with the needs of the tissues or a state in which abnormally elevated filling pressures are required for the heart to do so. Heart failure is frequently related to a defect in myocardial contraction. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:608751)
- Left ventricular hypertrophy (HP:0001712): Enlargement or increased size of the heart left ventricle. Evidence: PCS. Frequency: 3/3. (PMID:12021217)
- Endocardial fibrosis (HP:0006685): The presence of excessive connective tissue in the endocardium. Evidence: PCS. (PMID:12021217)
- Palpitations (HP:0001962): A sensation that the heart is pounding or racing, which is a non-specific sign but may be a manifestation of arrhythmia. Evidence: TAS. (OMIM:608751)
- 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:8673105)
- 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: TAS. (OMIM:608751)
- Exertional dyspnea (HP:0002875): Perceived difficulty to breathe that occurs with exercise or exertion and improves with rest. Evidence: TAS. (OMIM:608751)
These phenotypes are associated with the disease hypertrophic cardiomyopathy 8 (OMIM:608751).