Phenotypes associated with the disease congenital myopathy 2b, severe infantile, autosomal recessive (OMIM:620265):
- 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: 7/7. (PMID:17187373)
- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 10/10. (PMID:17187373;PMID:15236405;PMID:10508519)
- Generalized muscle weakness (HP:0003324): Generalized weakness or decreased strength of the muscles, affecting both distal and proximal musculature. Evidence: PCS. Frequency: 3/3. (PMID:15236405;PMID:10508519)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: PCS. Frequency: 6/7. (PMID:17187373)
- Bradycardia (HP:0001662): A slower than normal heart rate (in adults, slower than 60 beats per minute). Evidence: PCS. Frequency: 2/7. (PMID:17187373)
- 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: 9/9. (PMID:17187373;PMID:10508519)
- 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: 3/3. (PMID:15236405;PMID:10508519)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: PCS. Frequency: 7/7. (PMID:17187373)
- Respiratory insufficiency (HP:0002093). Evidence: PCS. Frequency: 2/2. (PMID:10508519)
- 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: 14/14. (PMID:17187373)
- Increased endomysial connective tissue (HP:0100297): An increased volume of the endomysium, which is a connective tissue sheath that surrounds each muscle fiber. Together, bundles of muscle fibers form a fasciculus, surrounded by another layer of connective tissue called the perimysium. Evidence: PCS. Frequency: 1/1. (PMID:15236405)
- Mildly elevated creatine kinase (HP:0008180). Evidence: PCS. Frequency: 2/7. (PMID:17187373)
- Death in childhood (HP:0003819): Death in during childhood, defined here as between the ages of 2 and 10 years. Evidence: PCS. Frequency: 1/7. (PMID:17187373)
- 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:10508519)
- Delayed ability to sit (HP:0025336): A failure to achieve the ability to sit at an appropriate developmental stage. Most children sit with support at 6 months of age and sit steadily without support at 9 months of age. Evidence: PCS. Frequency: 7/7. (PMID:17187373)
- Neonatal death (HP:0003811): Death within the first 28 days of life. Evidence: PCS. Frequency: 2/2. (PMID:10508519)
- Death in infancy (HP:0001522): Death within the first 24 months of life. Evidence: PCS. Frequency: 4/7. (PMID:17187373)
- Nemaline bodies (HP:0003798): Nemaline rods are abnormal bodies that can occur in skeletal muscle fibers. The rods can be observed on histological analysis of muscle biopsy tissue or upon electron microscopy, where they appear either as extensions of sarcomeric Z-lines, in random array without obvious attachment to Z-lines (often in areas devoid of sarcomeres) or in large clusters localized at the sarcolemma or intermyofibrillar spaces. Evidence: PCS. Frequency: 3/3. (PMID:15236405;PMID:10508519)
- 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: 1/1. (PMID:15236405)
- Respiratory failure requiring assisted ventilation (HP:0004887): A state of respiratory distress that requires a life saving intervention in the form of gaining airway access and instituting positive pressure ventilation. Evidence: PCS. Frequency: 1/1. (PMID:15236405)