- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 2/2. (PMID:17160903)
- 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: 0/2. (PMID:22560515)
- 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: 2/2. Onset: Congenital onset (HP:0003577). (PMID:17160903)
- 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: 1/2. (PMID:22560515)
- Fatty replacement of skeletal muscle (HP:0012548): Muscle fibers degeneration resulting in fatty replacement of skeletal muscle fibers. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- Limb muscle weakness (HP:0003690): Reduced strength and weakness of the muscles of the arms and legs. Evidence: PCS. Frequency: 2/2. (PMID:22560515)
- Abnormally low-pitched voice (HP:0010300): A persistent (minutes to hours) abnormal decrease in the pitch of the voice for the context or social situation or significantly different from the baseline of the individual. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 1/1. (PMID:22560515)
- Gowers sign (HP:0003391): A phenomenon whereby patients are not able to stand up without the use of the hands owing to weakness of the proximal muscles of the lower limbs. Evidence: PCS. Frequency: 2/2. (PMID:22560515)
- 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: 1/2. (PMID:22560515)
- 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: 1/2. (PMID:22560515)
- Muscle fibrillation (HP:0010546): Fine, rapid twitching of individual muscle fibers with little or no movement of the muscle as a whole as ascertained by electromyography (EMG). If a motor neuron or its axon is destroyed, the muscle fibers it innervates undergo denervation atrophy. This leads to hypersensitivity of individual muscle fibers to acetyl choline so that they may contract spontaneously. Isolated activity of individual muscle fibers is generally so fine it cannot be seen through the intact skin, although it can be recorded as a short-duration spike in the EMG. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 2/2. (PMID:22560515)
- Lower limb muscle weakness (HP:0007340): Weakness of the muscles of the legs. Evidence: PCS. Frequency: 2/2. (PMID:22560515)
- Genu recurvatum (HP:0002816): An abnormally increased extension of the knee joint, so that the knee can bend backwards. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- Lumbar hyperlordosis (HP:0002938): An abnormal accentuation of the inward curvature of the spine in the lumbar region. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- Waddling gait (HP:0002515): Weakness of the hip girdle and upper thigh muscles, for instance in myopathies, leads to an instability of the pelvis on standing and walking. If the muscles extending the hip joint are affected, the posture in that joint becomes flexed and lumbar lordosis increases. The patients usually have difficulties standing up from a sitting position. Due to weakness in the gluteus medius muscle, the hip on the side of the swinging leg drops with each step (referred to as Trendelenburg sign). The gait appears waddling. The patients frequently attempt to counteract the dropping of the hip on the swinging side by bending the trunk towards the side which is in the stance phase (in the German language literature this is referred to as Duchenne sign). Similar gait patterns can be caused by orthopedic conditions when the origin and the insertion site of the gluteus medius muscle are closer to each other than normal, for instance due to a posttraumatic elevation of the trochanter or pseudarthrosis of the femoral neck. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- 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: 1/2. (PMID:22560515)
- 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: PCS. Frequency: 2/2. (PMID:22560515)
- Frequent falls (HP:0002359). Evidence: PCS. Frequency: 2/2. (PMID:17160903)
- Minicore myopathy (HP:0003789): Multiple small zones of sarcomeric disorganization and lack of oxidative activity (known as minicores) in muscle fibers. Evidence: PCS. Frequency: 2/2. (PMID:17160903)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: PCS. Frequency: 2/2. (PMID:17160903)
- 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: PCS. Frequency: 2/2. (PMID:22560515)
- Pes planus (HP:0001763): A foot where the longitudinal arch of the foot is in contact with the ground or floor when the individual is standing; or, in a patient lying supine, a foot where the arch is in contact with the surface of a flat board pressed against the sole of the foot by the examiner with a pressure similar to that expected from weight bearing; or, the height of the arch is reduced. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- Z-band streaming (HP:0020203): Streaming or smearing of the Z band, which is then no longer confined to a narrow zone which bisects the I band. The Z disk may extend across the I band or the entire sarcomere in a zigzag manner. Focal thickening, smudging, and blurring of the Z band takes place concurrently. Myofibrillar disorganization is a frequent but not invariable accompanying change. Evidence: PCS. Frequency: 1/1. (PMID:22560515)
- Breech presentation (HP:0001623): A position of the fetus at delivery in which the fetus enters the birth canal with the buttocks or feet first. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- Kyphoscoliosis (HP:0002751): An abnormal curvature of the spine in both a coronal (lateral) and sagittal (back-to-front) plane. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- Centrally nucleated skeletal muscle fibers (HP:0003687): An abnormality in which the nuclei of sarcomeres take on an abnormally central localization (or in which this feature is found in an increased proportion of muscle cells). Evidence: PCS. Frequency: 2/2. (PMID:22560515)
- Delayed ability to walk (HP:0031936): A failure to achieve the ability to walk at an appropriate developmental stage. Most children learn to walk in a series of stages, and learn to walk short distances independently between 12 and 15 months. Evidence: PCS. Frequency: 2/2. (PMID:22560515)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: PCS. (PMID:22560515)
- Upper limb muscle weakness (HP:0003484): Weakness of the muscles of the arms. Evidence: PCS. Frequency: 2/2. (PMID:22560515)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- 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: PCS. Frequency: 4/4. (PMID:17160903;PMID:22560515)
- Knee contracture (HP:0034671): Lack of full passive range of motion (restrictions in flexion, extension, or other movements) of the knee joint resulting from structural changes of non-bony tissues, such as muscles, tendons, ligaments, joint capsules and/or skin. Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- 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:17160903)
- Respiratory insufficiency due to muscle weakness (HP:0002747). Evidence: PCS. Frequency: 1/2. (PMID:22560515)
- 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: 3/4. (PMID:17160903;PMID:22560515)
- Slowly progressive (HP:0003677): Applies to a disease manifestation that only slowly increases in scope or severity over the course of time. Evidence: PCS. (PMID:17160903)
- 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: 2/2. (PMID:22560515)
- Neck muscle weakness (HP:0000467): Decreased strength of the neck musculature. Evidence: PCS. Frequency: 2/2. (PMID:22560515)
These phenotypes are associated with the disease nemaline myopathy 7 (OMIM:610687).