- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 4/7. (PMID:32776697)
- Pyloric stenosis (HP:0002021): Pyloric stenosis, also known as infantile hypertrophic pyloric stenosis, is an uncommon condition in infants characterized by abnormal thickening of the pylorus muscles in the stomach leading to gastric outlet obstruction. Clinically infants are well at birth. Then, at 3 to 6 weeks of age, the infants present with projectile vomiting, potentially leading to dehydration and weight loss. Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- 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. Frequency: 7/7. Onset: Congenital onset (HP:0003577). (PMID:32776697)
- Weakness of facial musculature (HP:0030319): Reduced strength of one or more muscles innervated by the facial nerve (the seventh cranial nerve). Evidence: PCS. Frequency: 7/7. (PMID:32776697)
- Thin corpus callosum (HP:0033725): An abnormally thin corpus callous, due to atrophy, hypoplasia or agenesis. This term is intended to be used in situations where it is not known if thinning of the corpus callosum (for instance, as visualized by magnetic resonance tomography) is due to abnormal development (e.g. a leukodystrophy) or atrophy following normal development (e.g. neurodegeneration). Evidence: PCS. Frequency: 2/7. (PMID:32776697)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: PCS. Frequency: 2/7. Onset: Infantile onset (HP:0003593). (PMID:32776697)
- Reduced forced vital capacity (HP:0032341): An abnormal reduction in the amount of air a person can expel following maximal inspiration. Evidence: PCS. Frequency: 2/7. (PMID:32776697)
- Fetal onset (HP:0011461): Onset prior to birth but after 8 weeks of embryonic development (corresponding to a gestational age of 10 weeks). Evidence: PCS. Frequency: 3/7. (PMID:32776697)
- Slow saccadic eye movements (HP:0000514): An abnormally slow velocity of the saccadic eye movements. Evidence: PCS. Frequency: 3/14. (PMID:32776697)
- Tongue fasciculations (HP:0001308): Fasciculations or fibrillation affecting the tongue muscle. Evidence: PCS. Frequency: 2/7. (PMID:32776697)
- Limited extraocular movements (HP:0007941): Limited mobility of the eye within its socket. Evidence: PCS. Frequency: 4/7. (PMID:32776697)
- Weak voice (HP:0001621): Reduced intensity (volume) of speech. Evidence: PCS. Frequency: 3/7. (PMID:32776697)
- Abnormally high-pitched voice (HP:0001620): A persistent (minutes to hours) abnormal increase in the pitch (frequency) of the voice for the context or social situation or significantly different from baseline of the individual. Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- 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: 4/7. (PMID:32776697)
- Cerebellar vermis hypoplasia (HP:0001320): Underdevelopment of the vermis of cerebellum. Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- Subvalvular aortic stenosis (HP:0001682): A fixed form of obstruction to blood flow across the left-ventricular outflow tract related to stenosis (narrowing) below the level of the aortic valve. Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- Cerebral atrophy (HP:0002059): Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum. Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: PCS. Frequency: 3/7. (PMID:32776697)
- Easy fatigability (HP:0003388): Increased susceptibility to fatigue. Evidence: PCS. Frequency: 2/7. (PMID:32776697)
- Dysarthria (HP:0001260): Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed. Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: PCS. Frequency: 6/7. (PMID:32776697)
- Knee flexion contracture (HP:0006380): A type of knee joint contracture in which the knee is in a fixed bent (flexed) configuration such that it cannot be straightened actively or passively. Evidence: PCS. Frequency: 4/7. (PMID:32776697)
- Mitral stenosis (HP:0001718): An abnormal narrowing of the orifice of the mitral valve. Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- 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:32776697)
- Decreased fetal movement (HP:0001558): An abnormal reduction in quantity or strength of fetal movements. Evidence: PCS. Frequency: 3/7. Onset: Fetal onset (HP:0011461). (PMID:32776697)
- Ankle flexion contracture (HP:0006466). Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- Respiratory insufficiency due to muscle weakness (HP:0002747). Evidence: PCS. Frequency: 2/7. (PMID:32776697)
- Elbow flexion contracture (HP:0002987): An elbow contracture that limits the ability of the elbow joint to be extended (straightened), meaning that the elbow is fixed in an flexed (bent) position. Evidence: PCS. Frequency: 1/7. (PMID:32776697)
- Weak cry (HP:0001612). Evidence: PCS. Frequency: 2/7. (PMID:32776697)
- Hypernasal speech (HP:0001611): A type of speech characterized by the presence of an abnormally increased nasal airflow during speech associated with structural abnormality of the nasal passages. Evidence: PCS. Frequency: 2/7. (PMID:32776697)
- 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: 1/7. (PMID:32776697)
These phenotypes are associated with the disease myasthenic syndrome, congenital, 7B, presynaptic, autosomal recessive (OMIM:619461).