- Severe short stature (HP:0003510): A severe degree of short stature, more than -4 SD from the mean corrected for age and sex. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Cerebral atrophy (HP:0002059): Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Hearing impairment (HP:0000365): A decreased magnitude of the sensory perception of sound. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Rigidity (HP:0002063): Continuous involuntary sustained muscle contraction. When an affected muscle is passively stretched, the degree of resistance remains constant regardless of the rate at which the muscle is stretched. This feature helps to distinguish rigidity from muscle spasticity. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Caesarean section (HP:0011410): Delivery of a fetus through surgical incisions made through the abdominal wall (laparotomy) and the uterine wall (hysterotomy). Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Decreased activity of mitochondrial complex I (HP:0011923): A reduction in the activity of the mitochondrial respiratory chain complex I, which is part of the electron transport chain in mitochondria. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Aspiration pneumonia (HP:0011951): Pneumonia due to the aspiration (breathing in) of food, liquid, or gastric contents into the upper respiratory tract. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Small for gestational age (HP:0001518): Smaller than normal size according to sex and gestational age related norms, defined as a weight below the 10th percentile for the gestational age. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Nasogastric tube feeding (HP:0040288): The condition of inability to eat normally treated by placement of a thin tube through the nose into the stomach that is then used to carry food. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Focal T2 hyperintense thalamic lesion (HP:0012692): A lighter than expected T2 signal on magnetic resonance imaging (MRI) of the thalamus. This term refers to a localized hyperintensity affecting a particular region of the thalamus. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- 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:30607703)
- Optic atrophy (HP:0000648): Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- 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: 1/1. (PMID:30607703)
- Intrauterine growth retardation (HP:0001511): An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Growth delay (HP:0001510): A deficiency or slowing down of growth pre- and postnatally. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Neonatal respiratory distress (HP:0002643): Respiratory difficulty as newborn. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
- Myoclonus (HP:0001336): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: PCS. Frequency: 1/1. (PMID:30607703)
These phenotypes are associated with the disease combined oxidative phosphorylation deficiency 51 (OMIM:619057).