Phenotypes associated with the disease congenital myasthenic syndrome 19 (OMIM:616720):
- Poor head control (HP:0002421): Difficulty to maintain correct position of the head while standing or sitting. Infant head lag is observed when the head seems to flop around or lags posteriorly behind the trunk. Several articles have maintained that head lag should be absent by age 3 to 4 months. Evidence: PCS. Frequency: 1/3. (PMID:26626625)
- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 3/3. (PMID:26626625)
- 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: PCS. Frequency: 2/3. (PMID:26626625)
- Barrel-shaped chest (HP:0001552): A rounded, bulging chest that resembles the shape of a barrel. That is, there is an increased anteroposterior diameter and usually some degree of kyphosis. Evidence: PCS. Frequency: 1/3. (PMID:26626625)
- Recurrent lower respiratory tract infections (HP:0002783): An increased susceptibility to lower respiratory tract infections as manifested by a history of recurrent lower respiratory tract infections. Evidence: PCS. Frequency: 3/3. (PMID:26626625)
- Distal joint hypermobility (HP:0020152): Lack of stability of a distal joint (e.g., finger). Evidence: PCS. Frequency: 2/3. (PMID:26626625)
- Hypotonia (HP:0001252): Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist. Evidence: PCS. (PMID:26626625)
- Distal muscle weakness (HP:0002460): Reduced strength of the musculature of the distal extremities. Evidence: PCS. Frequency: 3/3. (PMID:26626625)
- Gastroesophageal reflux (HP:0002020): A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter. Evidence: PCS. Frequency: 1/3. (PMID:26626625)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: PCS. Frequency: 1/3. (PMID:26626625)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 1/3. (PMID:26626625)
- 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: PCS. Frequency: 3/3. (PMID:26626625)
- Axial muscle weakness (HP:0003327): Reduced strength of the axial musculature (i.e., of the muscles of the head and neck, spine, and ribs). Evidence: PCS. Frequency: 3/3. (PMID:26626625)
- Proximal muscle weakness (HP:0003701): A lack of strength of the proximal muscles. Evidence: PCS. Frequency: 2/3. (PMID:26626625)
- Retrognathia (HP:0000278): An abnormality in which the mandible is mislocalised posteriorly. Evidence: PCS. Frequency: 1/3. (PMID:26626625)
- Spinal rigidity (HP:0003306): Reduced ability to move the vertebral column with a resulting limitation of neck and trunk flexion. Evidence: PCS. Frequency: 2/3. (PMID:26626625)
- 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: PCS. Frequency: 2/2. (PMID:26626625)
- Exercise intolerance (HP:0003546): A functional motor deficit where individuals whose responses to the challenges of exercise fail to achieve levels considered normal for their age and gender. Evidence: PCS. Frequency: 3/3. (PMID:26626625)
- Increased jitter at single fiber EMG (HP:0030205): The variation in the time interval between the two action potentials of the same motor unit is called jitter. This term therefore applies to increased variability in the interval between successive action potentials of the same motor unit, which is measured by electromyography (EMG). Evidence: PCS. Frequency: 2/2. (PMID:26626625)
- Pes cavus (HP:0001761): An increase in height of the medial longitudinal arch of the foot that does not flatten on weight bearing (i.e., a distinctly hollow form of the sole of the foot when it is bearing weight). Evidence: PCS. Frequency: 1/3. (PMID:26626625)
- Bulbar palsy (HP:0001283): Bulbar weakness (or bulbar palsy) refers to bilateral impairment of function of the lower cranial nerves IX, X, XI and XII, which occurs due to lower motor neuron lesion either at nuclear or fascicular level in the medulla or from bilateral lesions of the lower cranial nerves outside the brain-stem. Bulbar weakness is often associated with difficulty in chewing, weakness of the facial muscles, dysarthria, palatal weakness and regurgitation of fluids, dysphagia, and dysphonia. Evidence: PCS. Frequency: 2/3. (PMID:26626625)
- Feeding difficulties (HP:0011968): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: PCS. Frequency: 3/3. (PMID:26626625)
- Respiratory insufficiency (HP:0002093). Evidence: PCS. Frequency: 2/3. (PMID:26626625)
- 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: PCS. Frequency: 3/3. (PMID:26626625)
- 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:26626625)
- Pectus carinatum (HP:0000768): A deformity of the chest caused by overgrowth of the ribs and characterized by protrusion of the sternum. Evidence: PCS. Frequency: 3/3. (PMID:26626625)
- Low-set ears (HP:0000369): Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the ear. Evidence: PCS. Frequency: 3/3. (PMID:26626625)
- Micrognathia (HP:0000347): Developmental hypoplasia of the mandible. Evidence: PCS. Frequency: 3/3. (PMID:26626625)
- Increased variability in muscle fiber diameter (HP:0003557): An abnormally high degree of muscle fiber size variation. This phenotypic feature can be observed upon muscle biopsy. Evidence: PCS. Frequency: 1/3. (PMID:26626625)