- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- High palate (HP:0000218): Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Abnormality of eye movement (HP:0000496): An abnormality in voluntary or involuntary eye movements or their control. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Ptosis (HP:0000508): The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Ophthalmoparesis (HP:0000597): Ophthalmoplegia is a paralysis or weakness of one or more of the muscles that control eye movement. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Diminished deep tendon reflex (HP:0001315): A reduction (hyporeflexia) or complete absence (areflexia) of the involuntary muscle contraction normally elicited by a reflex stimulus, such as tapping a deep tendon. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Abnormality of the musculature of the upper limbs (HP:0001446). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Skeletal muscle atrophy (HP:0003202): The presence of skeletal muscular atrophy (which is also known as amyotrophy). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Easy fatigability (HP:0003388): Increased susceptibility to fatigue. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Decreased miniature endplate potentials (HP:0003402): An abnormal reduction in the amplitude of the miniature endplate potentials, i.e. the postsynaptic response to transmitter released from an individual vesicle at the neuromuscular junction. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- EMG: decremental response of compound muscle action potential to repetitive nerve stimulation (HP:0003403): A compound muscle action potential (CMAP) is a type of electromyography (EMG). CMAP refers to a group of almost simultaneous action potentials from several muscle fibers in the same area evoked by stimulation of the supplying motor nerve and are recorded as one multipeaked summated action potential. This abnormality refers to a greater than normal decrease in the amplitude during the course of the investigation. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Decreased size of nerve terminals (HP:0003443): A reduction in the size of nerve terminals. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- EMG: myopathic abnormalities (HP:0003458): The presence of abnormal electromyographic patterns indicative of myopathy, such as small-short polyphasic motor unit potentials. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Upper limb muscle weakness (HP:0003484): Weakness of the muscles of the arms. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Shoulder girdle muscle weakness (HP:0003547): The shoulder, or pectoral, girdle is composed of the clavicles and the scapulae. Shoulder-girdle weakness refers to lack of strength of the muscles attaching to these bones, that is, lack of strength of the muscles around the shoulders. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Neck flexor weakness (HP:0003722): Weakness of the muscles involved in neck flexion (sternocleidomastoid, longus capitus, longus colli, and scalenus anterior). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Type 1 muscle fiber predominance (HP:0003803): An abnormal predominance of type I muscle fibers (in general, this feature can only be observed on muscle biopsy). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Weakness of the intrinsic hand muscles (HP:0009005). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Facial palsy (HP:0010628): Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Fatigable weakness of neck muscles (HP:0030199): A type of weakness of a skeletal muscle in the neck that occurs after a muscle group is used and lessens if the muscle group has some rest. That is, there is diminution of strength with repetitive muscle actions. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Abnormality of masticatory muscle (HP:0410011): Any abnormality of the masticatory muscle. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98913)
- Diplopia (HP:0000651): Diplopia is a condition in which a single object is perceived as two images, it is also known as double vision. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Cyanosis (HP:0000961): Bluish discoloration of the skin and mucosa due to poor circulation or inadequate oxygenation of arterial or capillary blood. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Restrictive ventilatory defect (HP:0002091): A functional defect characterized by reduced total lung capacity (TLC) not associated with abnormalities of expiratory airflow or airway resistance. Spirometrically, a restrictive defect is defined as FEV1 (forced expiratory volume in 1 second) and FVC (forced vital capacity) less than 80 per cent. Restrictive lung disease may be caused by alterations in lung parenchyma or because of a disease of the pleura, chest wall, or neuromuscular apparatus. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Delayed gross motor development (HP:0002194): A type of motor delay characterized by a delay in acquiring the ability to control the large muscles of the body for walking, running, sitting, and crawling. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Drowsiness (HP:0002329): Abnormal feeling of sleepiness or difficulty staying awake. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Reduced vital capacity (HP:0002792): An abnormal reduction on the vital capacity, which is defined as the total lung capacity (volume of air in the lungs at maximal inflation) less the residual volume (i.e., volume of air in the lungs following maximal exhalation) of the lung. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Exertional dyspnea (HP:0002875): Perceived difficulty to breathe that occurs with exercise or exertion and improves with rest. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Respiratory failure (HP:0002878): A severe form of respiratory insufficiency characterized by inadequate gas exchange such that the levels of oxygen or carbon dioxide cannot be maintained within normal limits. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Thoracic kyphoscoliosis (HP:0005659). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Weakness of long finger extensor muscles (HP:0009077). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Hip flexor weakness (HP:0012515): Reduced ability to flex the femur, that is, to pull the knee upward. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Orthopnea (HP:0012764): A sensation of breathlessness in the recumbent position, relieved by sitting or standing. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Fatigable weakness of respiratory muscles (HP:0030196): A type of weakness of the muscles involved in breathing (respiration) that occurs after a muscle group is used and lessens if the muscle group has some rest. That is, there is diminution of strength with repetitive muscle actions. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Triceps weakness (HP:0031108): A lack of strength in the triceps muscle, which normally is responsible for extending (straightening) the elbow and mediating certain shoulder movements. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
- Ankle weakness (HP:0031374): Reduced strength of the muscles that lift or otherwise move the foot at the ankle. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98913)
These phenotypes are associated with the disease Postsynaptic congenital myasthenic syndrome (ORPHA:98913).