- Hearing impairment (HP:0000365): A decreased magnitude of the sensory perception of sound. Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Hydrocele testis (HP:0000034): Accumulation of clear fluid in the between the layers of membrane (tunica vaginalis) surrounding the testis. Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Increased circulating lactate concentration (HP:0002151): Abnormally increased level of blood lactate (2-hydroxypropanoic acid). Lactate is produced from pyruvate by lactate dehydrogenase during normal metabolism. The terms lactate and lactic acid are often used interchangeably but lactate (the component measured in blood) is strictly a weak base whereas lactic acid is the corresponding acid. Lactic acidosis is often used clinically to describe elevated lactate but should be reserved for cases where there is a corresponding acidosis (pH below 7.35). Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Tetraparesis (HP:0002273): Weakness of all four limbs. Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Multifocal epileptiform discharges (HP:0010841): An abnormality in cerebral electrical activity recorded along the scalp by electroencephalography (EEG) and being identified at multiple locations (foci). Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- 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:29211846)
- Dyskinesia (HP:0100660): A movement disorder which consists of effects including diminished voluntary movements and the presence of involuntary movements. Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Infantile spasms (HP:0012469): Infantile spasms represent a subset of "epileptic spasms". Infantile Spasms are epileptic spasms starting in the first year of life (infancy). Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Depletion of mitochondrial DNA in muscle tissue (HP:0009141). Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- 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:29211846)
- Microcytic anemia (HP:0001935): A kind of anemia in which the volume of the red blood cells is reduced. Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Spasticity (HP:0001257): A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes. Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Hypospadias (HP:0000047): Abnormal position of urethral meatus on the ventral penile shaft (underside) characterized by displacement of the urethral meatus from the tip of the glans penis to the ventral surface of the penis, scrotum, or perineum. Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- Focal-onset seizure (HP:0007359): A focal-onset seizure is a type of seizure originating within networks limited to one hemisphere. They may be discretely localized or more widely distributed, and may originate in subcortical structures. Evidence: PCS. Frequency: 1/1. (PMID:29211846)
- 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:29211846)
These phenotypes are associated with the disease mitochondrial DNA depletion syndrome 19 (OMIM:618972).