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Mitochondrial complex III deficiency nuclear type 2(MC3DN2)

MedGen UID:
767519
Concept ID:
C3554605
Disease or Syndrome
Synonyms: MC3DN2; MITOCHONDRIAL COMPLEX III DEFICIENCY, NUCLEAR TYPE 2
 
Gene (location): TTC19 (17p12)
 
Monarch Initiative: MONDO:0014063
OMIM®: 615157

Definition

Mitochondrial complex III deficiency nuclear type 2 is an autosomal recessive severe neurodegenerative disorder that usually presents in childhood, but may show later onset, even in adulthood. Affected individuals have motor disability, with ataxia, apraxia, dystonia, and dysarthria, associated with necrotic lesions throughout the brain. Most patients also have cognitive impairment and axonal neuropathy and become severely disabled later in life (summary by Ghezzi et al., 2011). The disorder may present clinically as spinocerebellar ataxia or Leigh syndrome, or with psychiatric disturbances (Morino et al., 2014; Atwal, 2014; Nogueira et al., 2013). For a discussion of genetic heterogeneity of mitochondrial complex III deficiency, see MC3DN1 (124000). [from OMIM]

Additional description

From MedlinePlus Genetics
Mitochondrial complex III deficiency can be fatal in childhood, although individuals with mild signs and symptoms can survive into adolescence or adulthood.

Most people with mitochondrial complex III deficiency have a buildup of a chemical called lactic acid in the body (lactic acidosis). Some affected individuals also have buildup of molecules called ketones (ketoacidosis) or high blood glucose levels (hyperglycemia). Abnormally high levels of these chemicals in the body can be life-threatening.

The severity of mitochondrial complex III deficiency varies widely among affected individuals. People who are mildly affected tend to have muscle weakness (myopathy) and extreme tiredness (fatigue), particularly during exercise (exercise intolerance). More severely affected individuals have problems with multiple body systems, such as liver disease that can lead to liver failure, kidney abnormalities (tubulopathy), and brain dysfunction (encephalopathy). Encephalopathy can cause delayed development of mental and motor skills (psychomotor delay), movement problems, weak muscle tone (hypotonia), and difficulty with communication. Some affected individuals have a form of heart disease called cardiomyopathy, which can lead to heart failure. 

Mitochondrial complex III deficiency is a genetic condition that can affect several parts of the body, including the brain, kidneys, liver, heart, and the muscles used for movement (skeletal muscles). Signs and symptoms of mitochondrial complex III deficiency usually begin in infancy but can appear later.  https://medlineplus.gov/genetics/condition/mitochondrial-complex-iii-deficiency

Clinical features

From HPO
Limb fasciculations
MedGen UID:
381469
Concept ID:
C1854657
Finding
Fasciculations affecting the musculature of the arms and legs.
Dysphagia
MedGen UID:
41440
Concept ID:
C0011168
Disease or Syndrome
Difficulty in swallowing.
Hearing impairment
MedGen UID:
235586
Concept ID:
C1384666
Disease or Syndrome
A decreased magnitude of the sensory perception of sound.
Aggressive behavior
MedGen UID:
1375
Concept ID:
C0001807
Individual Behavior
Behavior or an act aimed at harming a person, animal, or physical property (e.g., acts of physical violence; shouting, swearing, and using harsh language; slashing someone's tires).
Anxiety
MedGen UID:
1613
Concept ID:
C0003467
Finding
Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control.
Apraxia
MedGen UID:
8166
Concept ID:
C0003635
Mental or Behavioral Dysfunction
A defect in the understanding of complex motor commands and in the execution of certain learned movements, i.e., deficits in the cognitive components of learned movements.
Cerebellar ataxia
MedGen UID:
849
Concept ID:
C0007758
Disease or Syndrome
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).
Coma
MedGen UID:
1054
Concept ID:
C0009421
Disease or Syndrome
The complete absence of wakefulness and consciousness, which is evident through a lack of response to any form of external stimuli.
Depression
MedGen UID:
4229
Concept ID:
C0011581
Mental or Behavioral Dysfunction
Frequently experiencing feelings of being down, miserable, and/or hopeless; struggling to recover from these moods; having a pessimistic outlook on the future; feeling a pervasive sense of shame; having a low self-worth; experiencing thoughts of suicide and engaging in suicidal behavior.
Dysarthria
MedGen UID:
8510
Concept ID:
C0013362
Mental or Behavioral Dysfunction
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.
Dystonic disorder
MedGen UID:
3940
Concept ID:
C0013421
Sign or Symptom
An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.
Hallucinations
MedGen UID:
6709
Concept ID:
C0018524
Mental or Behavioral Dysfunction
Perceptions in a conscious and awake state that, in the absence of external stimuli, have qualities of real perception. These perceptions are vivid, substantial, and located in external objective space.
Intellectual disability, mild
MedGen UID:
10044
Concept ID:
C0026106
Mental or Behavioral Dysfunction
Mild intellectual disability is defined as an intelligence quotient (IQ) in the range of 50-69.
Neurodegeneration
MedGen UID:
17999
Concept ID:
C0027746
Cell or Molecular Dysfunction
Progressive loss of neural cells and tissue.
Olivopontocerebellar atrophy
MedGen UID:
10435
Concept ID:
C0028968
Disease or Syndrome
Neuronal degeneration in the cerebellum, pontine nuclei, and inferior olivary nucleus.
Psychotic disorder
MedGen UID:
19568
Concept ID:
C0033975
Mental or Behavioral Dysfunction
A condition characterized by changes in personality and thought patterns, often accompanied by hallucinations and delusional beliefs, is known as psychosis.
Babinski sign
MedGen UID:
19708
Concept ID:
C0034935
Finding
Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract.
Spastic paraparesis
MedGen UID:
52432
Concept ID:
C0037771
Sign or Symptom
Mild or moderate loss of motor function accompanied by spasticity in the lower extremities. This condition is a manifestation of CENTRAL NERVOUS SYSTEM DISEASES that cause injury to the motor cortex or descending motor pathways.
Tremor
MedGen UID:
21635
Concept ID:
C0040822
Sign or Symptom
An unintentional, oscillating to-and-fro muscle movement about a joint axis.
Hyperreflexia
MedGen UID:
57738
Concept ID:
C0151889
Finding
Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.
Paraparesis
MedGen UID:
113150
Concept ID:
C0221166
Sign or Symptom
Weakness or partial paralysis in the lower limbs.
Bradykinesia
MedGen UID:
115925
Concept ID:
C0233565
Sign or Symptom
Bradykinesia literally means slow movement, and is used clinically to denote a slowness in the execution of movement (in contrast to hypokinesia, which is used to refer to slowness in the initiation of movement).
Dysmetria
MedGen UID:
68583
Concept ID:
C0234162
Finding
A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements.
Resting tremor
MedGen UID:
66697
Concept ID:
C0234379
Sign or Symptom
A resting tremor occurs when muscles are at rest and becomes less noticeable or disappears when the affected muscles are moved. Resting tremors are often slow and coarse.
Dysdiadochokinesis
MedGen UID:
115975
Concept ID:
C0234979
Sign or Symptom
A type of ataxia characterized by the impairment of the ability to perform rapidly alternating movements, such as pronating and supinating his or her hand on the dorsum of the other hand as rapidly as possible.
Cerebral atrophy
MedGen UID:
116012
Concept ID:
C0235946
Disease or Syndrome
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
Cognitive impairment
MedGen UID:
90932
Concept ID:
C0338656
Mental or Behavioral Dysfunction
Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering.
Abnormal diminished volition
MedGen UID:
96830
Concept ID:
C0456814
Finding
A reduction in willful and motivated goal-directed behavior that is considered the determinant of behavior and adaptation that allows individuals to get started, be energized to perform a sustained and directed action.
Incoordination
MedGen UID:
141714
Concept ID:
C0520966
Finding
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Compulsive behaviors
MedGen UID:
109373
Concept ID:
C0600104
Mental or Behavioral Dysfunction
Behavior that consists of repetitive acts, characterized by the feeling that one "has to" perform them, while being aware that these acts are not in line with one's overall goal.
Cerebellar atrophy
MedGen UID:
196624
Concept ID:
C0740279
Disease or Syndrome
Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event.
Limb ataxia
MedGen UID:
196692
Concept ID:
C0750937
Finding
A kind of ataxia that affects movements of the extremities.
Gait ataxia
MedGen UID:
155642
Concept ID:
C0751837
Sign or Symptom
A type of ataxia characterized by the impairment of the ability to coordinate the movements required for normal walking. Gait ataxia is characteirzed by a wide-based staggering gait with a tendency to fall.
Gait apraxia
MedGen UID:
266930
Concept ID:
C1510417
Disease or Syndrome
Gait apraxia affecting the ability to make walking movements with the legs.
Cognitive regression
MedGen UID:
815091
Concept ID:
C3808761
Finding
Loss of cognitive developmental skills, as manifested by loss of developmental cognitive milestones.
Peripheral axonal degeneration
MedGen UID:
871339
Concept ID:
C4025830
Finding
Progressive deterioration of peripheral axons.
Cerebral cortical atrophy
MedGen UID:
1646740
Concept ID:
C4551583
Disease or Syndrome
Atrophy of the cortex of the cerebrum.
Reduced social responsiveness
MedGen UID:
1841569
Concept ID:
C5826975
Finding
A reduced ability to participate in the back-and-forth flow of social interaction appropriate to culture and developmental level, which is normally characterized by an influence of the behavior of one person on the behavior of another person. This results in difficulty interacting with others through emotional, physical, or verbal communication.
Scoliosis
MedGen UID:
11348
Concept ID:
C0036439
Disease or Syndrome
The presence of an abnormal lateral curvature of the spine.
Muscle weakness
MedGen UID:
57735
Concept ID:
C0151786
Finding
Reduced strength of muscles.
Muscular atrophy
MedGen UID:
892680
Concept ID:
C0541794
Pathologic Function
The presence of skeletal muscular atrophy (which is also known as amyotrophy).
Central apnea
MedGen UID:
854403
Concept ID:
C3887548
Disease or Syndrome
Apnea resulting from depression of the respiratory centers in the medulla oblongata. There is a lack of respiratory effort rather than obstruction of airflow.
Dysphonia
MedGen UID:
282893
Concept ID:
C1527344
Mental or Behavioral Dysfunction
Difficulty in speaking due to a physical disorder of the mouth, tongue, throat, or vocal cords. Associated with a known physical or neurological cause.
Diplopia
MedGen UID:
41600
Concept ID:
C0012569
Disease or Syndrome
Diplopia is a condition in which a single object is perceived as two images, it is also known as double vision.
Nystagmus
MedGen UID:
45166
Concept ID:
C0028738
Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.
Decreased activity of mitochondrial complex III
MedGen UID:
460434
Concept ID:
C3149083
Finding
A reduction in the activity of the mitochondrial respiratory chain complex III, which is part of the electron transport chain in mitochondria.

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