Phenotypes associated with the disease mitochondrial complex IV deficiency, nuclear type 17 (OMIM:619061):
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: PCS. Frequency: 1/6. (PMID:25175347)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: PCS. Frequency: 5/6. (PMID:25175347)
- Seizure (HP:0001250): A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Evidence: PCS. Frequency: 2/6. (PMID:25175347)
- Dysarthria (HP:0001260): Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed. Evidence: PCS. Frequency: 2/6. (PMID:25175347)
- Spastic tetraparesis (HP:0001285): Spastic weakness affecting all four limbs. Evidence: PCS. Frequency: 5/6. (PMID:25175347)
- Ataxia (HP:0001251): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: PCS. Frequency: 2/6. (PMID:25175347)
- Cavitating leukodystrophy (HP:0033369): A type of leukodystrophy characterized by multiple small cavitations typically in the periventricular and deep cerebral white matter. The cavitations are visible as a central cavity with cerebrospinal fluid-like signal intensity. Evidence: PCS. Frequency: 6/6. (PMID:25175347)
- Sensorimotor neuropathy (HP:0007141). Evidence: PCS. Frequency: 3/6. (PMID:25175347)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 6/6. (PMID:25175347)
- 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:25175347)
- Decreased activity of mitochondrial complex IV (HP:0008347): A reduction in the activity of the mitochondrial respiratory chain complex IV, which is part of the electron transport chain in mitochondria. Evidence: PCS. Frequency: 6/6. (PMID:25175347)
- Intellectual disability (HP:0001249): The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence. Evidence: PCS. Frequency: 3/6. (PMID:25175347)
- Cytochrome C oxidase-negative muscle fibers (HP:0003688): An abnormally reduced activity of the enzyme cytochrome C oxidase in muscle tissue. Evidence: PCS. (PMID:25175347)