- Vitiligo (HP:0001045). Evidence: IEA. (OMIM:184850)
- Opisthotonus (HP:0002179): Opisthotonus is defined as a dramatic abnormal posture due to spastic contraction of the extensor muscles of the neck, trunk, and lower extremities that produces a severe backward arching from neck to heel. In most cases, the trunk is elevated off the ground by a few inches. It is usually sudden in onset and can be sustained or repetitive. It can be considered a variant of decerebrate posturing involving a hyperextension of the neck, back, and limbs. Evidence: IEA. (OMIM:184850)
- Exaggerated startle response (HP:0002267): An exaggerated startle reaction in response to a sudden unexpected visual or acoustic stimulus, or a quick movement near the face. Evidence: IEA. (OMIM:184850)
- Autoimmunity (HP:0002960): The occurrence of an immune reaction against the organism's own cells or tissues. Evidence: TAS. (OMIM:184850)
- Rigidity (HP:0002063): Continuous involuntary sustained muscle contraction. When an affected muscle is passively stretched, the degree of resistance remains constant regardless of the rate at which the muscle is stretched. This feature helps to distinguish rigidity from muscle spasticity. Evidence: IEA. (OMIM:184850)
- Adult onset (HP:0003581): Onset of disease manifestations in adulthood, defined here as at the age of 16 years or later. Evidence: IEA. (OMIM:184850)
- Diabetes mellitus (HP:0000819): A group of abnormalities characterized by hyperglycemia and glucose intolerance. Evidence: IEA. (OMIM:184850)
- Depression (HP:0000716): Frequently experiencing feelings of being down, miserable, and/or hopeless; struggling to recover from these moods; having a pessimistic outlook on the future; feeling a pervasive sense of shame; having a low self-worth; experiencing thoughts of suicide and engaging in suicidal behavior. Evidence: IEA. (OMIM:184850)
- Anemia (HP:0001903): A reduction in erythrocytes volume or hemoglobin concentration. Evidence: IEA. (OMIM:184850)
- Proximal limb muscle stiffness (HP:0007066): Stiffness of the limbs (a condition in which muscles cannot be moved quickly without accompanying pain or spasm) occurring in the proximal limb muscle. Evidence: IEA. (OMIM:184850)
- Anxiety (HP:0000739): Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control. Evidence: IEA. (OMIM:184850)
- Lumbar hyperlordosis (HP:0002938): An abnormal accentuation of the inward curvature of the spine in the lumbar region. Evidence: IEA. (OMIM:184850)
- Agoraphobia (HP:0000756): A type of anxiety disorder characterized by the avoidance of public places, especially where crowds gather. Evidence: IEA. (OMIM:184850)
- Hypertension (HP:0000822): The presence of chronic increased pressure in the systemic arterial system. Evidence: IEA. (OMIM:184850)
- Asymmetric limb muscle stiffness (HP:0007156): Stiffness of the limbs (a condition in which muscles cannot be moved quickly without accompanying pain or spasm) occurring in an asymmetric pattern. Evidence: IEA. (OMIM:184850)
- Hyperhidrosis (HP:0000975): Abnormal excessive perspiration (sweating) despite the lack of appropriate stimuli like hot and humid weather. Evidence: IEA. (OMIM:184850)
- Myoclonic spasms (HP:0003739). Evidence: TAS. (OMIM:184850)
- Tachycardia (HP:0001649): A rapid heartrate that exceeds the range of the normal resting heartrate for age. Evidence: IEA. (OMIM:184850)
- Fever (HP:0001945): Body temperature elevated above the normal range. Evidence: TAS. (OMIM:184850)
- Sporadic (HP:0003745): Cases of the disease in question occur without a previous family history, i.e., as isolated cases without being transmitted from a parent and without other siblings being affected. Evidence: IEA. (OMIM:184850)
- Frequent falls (HP:0002359). Evidence: IEA. (OMIM:184850)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: IEA. (OMIM:184850)
- Axial muscle stiffness (HP:0006921): Stiffness (a condition in which muscles cannot be moved quickly without accompanying pain or spasm) of the axial musculature. Evidence: IEA. (OMIM:184850)
These phenotypes are associated with the disease stiff-person syndrome (OMIM:184850).