Phenotypes associated with the disease myopathy, reducing body, X-linked, early-onset, severe (OMIM:300717):
- Hyporeflexia (HP:0001265): Reduction of neurologic reflexes such as the knee-jerk reaction. Evidence: IEA. (OMIM:300717)
- 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: 1/2. (PMID:18274675)
- Elevated circulating creatine kinase activity (HP:0003236): The activity of creatine kinase in the blood circulation is above the upper limit of normal. Evidence: PCS. Frequency: 2/2. (PMID:18274675)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: PCS. Frequency: 1/2. (PMID:18274675)
- Flexion contracture (HP:0001371): A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints. Evidence: IEA. (OMIM:300717)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: IEA. (OMIM:300717)
- Death in adolescence (HP:0011421): Death during adolescence, the period between childhood and adulthood (roughly between the ages of 10 and 16 years). Evidence: PCS. Frequency: 1/2. (PMID:18274675)
- Muscle fiber intracytoplasmic reducing inclusion bodies (HP:0034320): Intracytoplasmic inclusions in myofibers that reduce nitro-blue tetrazolium (NBT) and thus stain strongly with the menadione-NBT stain. Evidence: PCS. Frequency: 2/2. (PMID:18274675)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 2/2. (PMID:18274675)
- 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: PCS. Frequency: 1/2. (PMID:18274675)
- Loss of ambulation (HP:0002505): Inability to walk in a person who previous had the ability to walk. Evidence: PCS. Frequency: 2/2. (PMID:18274675)
- Respiratory insufficiency due to muscle weakness (HP:0002747). Evidence: PCS. Frequency: 2/2. (PMID:18274675)
- Proximal muscle weakness (HP:0003701): A lack of strength of the proximal muscles. Evidence: PCS. Frequency: 2/2. (PMID:18274675)
- X-linked dominant inheritance (HP:0001423): A mode of inheritance that is observed for dominant traits related to a gene encoded on the X chromosome. In the context of medical genetics, X-linked dominant disorders tend to manifest very severely in affected males. The severity of manifestation in females may depend on the degree of skewed X inactivation. Evidence: PCS. (PMID:18274675)
- Spinal rigidity (HP:0003306): Reduced ability to move the vertebral column with a resulting limitation of neck and trunk flexion. Evidence: PCS. Frequency: 1/2. (PMID:18274675)
- 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: IEA. (OMIM:300717)
- Rapidly progressive (HP:0003678): Applies to a disease manifestation that quickly increases in scope or severity over the course of time. Evidence: PCS. (PMID:18274675)