- Hyporeflexia (HP:0001265): Reduction of neurologic reflexes such as the knee-jerk reaction. Evidence: PCS. Frequency: 3/7. (PMID:20074522)
- Middle age onset (HP:0003596): A type of adult onset with onset of symptoms at the age of 40 to 60 years. Evidence: PCS. Frequency: 1/8. (PMID:20074522)
- Increased circulating T4 concentration (HP:0031506): An elevation above the normal concentration of thyroxine in the blood. Thyroxine (also known as T4) is the main hormone secreted by the thyroid gland into the blood. It can be converted into the active form triiodothyronine (also known as T3). Evidence: PCS. Frequency: 2/2. (PMID:20074522)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: PCS. Frequency: 3/7. (PMID:20074522)
- Hyperthyroidism (HP:0000836): An abnormality of thyroid physiology characterized by excessive secretion of the thyroid hormones thyroxine (i.e., T4) and/or 3,3',5-triiodo-L-thyronine zwitterion (i.e., triiodothyronine or T3). Evidence: PCS. (PMID:20074522)
- Increased circulating free T4 concentration (HP:0033077): An elevated concentration of free thyroxine (fT4) in the blood circulation. Evidence: PCS. Frequency: 6/7. (PMID:20074522)
- Young adult onset (HP:0011462): Onset of disease at the age of between 16 and 40 years. Evidence: PCS. Frequency: 7/8. (PMID:20074522)
- Decreased thyroid-stimulating hormone level (HP:0031098): Reduced amount of the thyroid-stimulating hormone (TSH), which is produced by the anterior pituitary gland and stimulates the function of the thyroid gland. Evidence: PCS. Frequency: 6/6. (PMID:20074522)
- Hypokalemia (HP:0002900): The concentration of potassium(1+) in the blood circulation is below the lower limit of normal. Evidence: PCS. Frequency: 8/8. (PMID:20074522)
- Tachycardia (HP:0001649): A rapid heartrate that exceeds the range of the normal resting heartrate for age. Evidence: PCS. Frequency: 7/8. (PMID:20074522)
- Weight loss (HP:0001824): Reduction of total body weight. Evidence: PCS. Frequency: 8/8. (PMID:20074522)
- Periodic paralysis (HP:0003768): Episodes of muscle weakness. Evidence: PCS. Frequency: 8/8. (PMID:20074522)
- 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:20074522)
- Goiter (HP:0000853): An enlargement of the thyroid gland. Evidence: PCS. Frequency: 6/8. (PMID:20074522)
- Tremor (HP:0001337): An unintentional, oscillating to-and-fro muscle movement about a joint axis. Evidence: PCS. Frequency: 7/8. (PMID:20074522)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: PCS. Frequency: 1/7. (PMID:20074522)
These phenotypes are associated with the disease thyrotoxic periodic paralysis, susceptibility to, 2 (OMIM:613239).