- 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: 1/1. (PMID:31469168)
- 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: 1/1. (PMID:31469168)
- Myopathy (HP:0003198): A disorder of muscle unrelated to impairment of innervation or neuromuscular junction. Evidence: PCS. Frequency: 1/1. (PMID:31469168)
- Delayed ability to stand (HP:0025335): A failure to achieve the ability to stand up at an appropriate developmental stage. Most children begin to walk alone at 11 to 15 months of age. On average, children can stand while holding on at the age of 9 to 10 months, can pull up to stand and walk with one hand being held at 12 months, and can stand alone and walk well at 18 months. Evidence: PCS. Frequency: 1/1. (PMID:31469168)
- Highly elevated creatine kinase (HP:0030234): An increased CPK level between 4X and 50X above the upper normal level. Evidence: PCS. Frequency: 1/1. (PMID:31469168)
- Generalized non-motor (absence) seizure (HP:0002121): A generalized non-motor (absence) seizure is a type of a type of dialeptic seizure that is of electrographically generalized onset. It is a generalized seizure characterized by an interruption of activities, a blank stare, and usually the person will be unresponsive when spoken to. Any ictal motor phenomena are minor in comparison to these non-motor features. Evidence: PCS. Frequency: 1/1. (PMID:31469168)
- 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:31469168)
- Abnormal periventricular white matter morphology (HP:0002518): A structural abnormality of the myelinated axons (white matter) located near the cerebral ventricles. Evidence: PCS. Frequency: 1/1. (PMID:31469168)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 1/1. (PMID:31469168)
- 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:31469168)
These phenotypes are associated with the disease muscular dystrophy-dystroglycanopathy (congenital with impaired intellectual development), type B, 15 (OMIM:618992).