Phenotypes associated with the disease Severe X-linked mitochondrial encephalomyopathy (ORPHA:238329):
- 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: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Areflexia (HP:0001284): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Skeletal muscle atrophy (HP:0003202): The presence of skeletal muscular atrophy (which is also known as amyotrophy). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Generalized muscle weakness (HP:0003324): Generalized weakness or decreased strength of the muscles, affecting both distal and proximal musculature. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Sensory axonal neuropathy (HP:0003390): An axonal neuropathy of peripheral sensory nerves. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- 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: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Severe muscular hypotonia (HP:0006829): A severe degree of muscular hypotonia characterized by markedly reduced muscle tone. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Peripheral neuropathy (HP:0009830): Peripheral neuropathy is a general term for any disorder of the peripheral nervous system. The main clinical features used to classify peripheral neuropathy are distribution, type (mainly demyelinating versus mainly axonal), duration, and course. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Abnormal corpus striatum morphology (HP:0010994): Abnormality of the striatum, which is the largest nucleus of the basal ganglia, comprising the caudate, putamen and ventral striatum, including the nucleus accumbens. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Moderate global developmental delay (HP:0011343): A moderate delay in the achievement of motor or mental milestones in the domains of development of a child. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:238329)
- Irritability (HP:0000737): An emotional state characterized by negative feelings of heightened frustration, annoyance, or feeling upset, often triggered by internal factors (e.g., fatigue, hunger, unfulfilled desires) or external factors (e.g., social or environmental challenges). Irritability may be unpredictable, and is accompanied by a lowered threshold for emotional reactivity and observable features (speech, facial expressions, or psychomotor activity). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Tongue fasciculations (HP:0001308): Fasciculations or fibrillation affecting the tongue muscle. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Respiratory insufficiency (HP:0002093). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Respiratory distress (HP:0002098): Respiratory distress is objectively observable as the physical or emotional consequences from the experience of dyspnea. The physical presentation of respiratory distress is generally referred to as labored breathing, while the sensation of respiratory distress is called shortness of breath or dyspnea. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- 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: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Hypokinesia (HP:0002375): Abnormally diminished motor activity. In contrast to paralysis, hypokinesia is not characterized by a lack of motor strength, but rather by a poverty of movement. The typical habitual movements (e.g., folding the arms, crossing the legs) are reduced in frequency. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Increased CSF lactate (HP:0002490): Increased concentration of lactate in the cerebrospinal fluid. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Increased circulating pyruvate concentration (HP:0003542): The concentration of pyruvate in the blood circulation is above the upper limit of normal. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Involuntary movements (HP:0004305): Involuntary contractions of muscle leading to involuntary movements of extremities, neck, trunk, or face. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Increased connective tissue (HP:0009025): The presence of an abnormally increased amount of connective tissue. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:238329)
- Feeding difficulties in infancy (HP:0008872): Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:238329)