U.S. flag

An official website of the United States government

Format

Send to:

Choose Destination

Cardioencephalomyopathy, fatal infantile, due to cytochrome c oxidase deficiency 1(MC4DN2)

MedGen UID:
1748867
Concept ID:
C5399977
Disease or Syndrome
Synonyms: Cardioencephalomyopathy, fatal infantile, due to cytochrome c oxidase deficiency; CYTOCHROME c OXIDASE DEFICIENCY, FATAL INFANTILE, WITH CARDIOENCEPHALOMYOPATHY; MC4DN2; MITOCHONDRIAL COMPLEX IV DEFICIENCY, NUCLEAR TYPE 2
 
Gene (location): SCO2 (22q13.33)
 
Monarch Initiative: MONDO:0011451
OMIM®: 604377

Definition

Mitochondrial complex IV deficiency nuclear type 2 (MC4DN2) is an autosomal recessive multisystem metabolic disorder characterized by the onset of symptoms at birth or in the first weeks or months of life. Affected individuals have severe hypotonia, often associated with feeding difficulties and respiratory insufficiency necessitating tube feeding and mechanical ventilation. The vast majority of patients develop hypertrophic cardiomyopathy in the first days or weeks of life, which usually leads to death in infancy or early childhood. Patients also show neurologic abnormalities, including developmental delay, nystagmus, fasciculations, dystonia, EEG changes, and brain imaging abnormalities compatible with a diagnosis of Leigh syndrome (see 256000). There may also be evidence of systemic involvement with hepatomegaly and myopathy, although neurogenic muscle atrophy is more common and may resemble spinal muscular atrophy type I (SMA1; 253300). Serum lactate is increased, and laboratory studies show decreased mitochondrial complex IV protein and activity levels in various tissues, including heart and skeletal muscle. Most patients die in infancy of cardiorespiratory failure (summary by Papadopoulou et al., 1999). For a discussion of genetic heterogeneity of mitochondrial complex IV (cytochrome c oxidase) deficiency, see 220110. [from OMIM]

Additional description

From MedlinePlus Genetics
Many individuals with cytochrome c oxidase deficiency do not survive past childhood, although some individuals with mild signs and symptoms live into adolescence or adulthood.

Many people with cytochrome c oxidase deficiency have a specific group of features known as Leigh syndrome. The signs and symptoms of Leigh syndrome include loss of mental function, movement problems, hypertrophic cardiomyopathy, eating difficulties, and brain abnormalities. Cytochrome c oxidase deficiency is one of the many causes of Leigh syndrome.

The severity of cytochrome c oxidase deficiency varies widely among affected individuals, even among those in the same family. People who are mildly affected tend to have muscle weakness (myopathy) and poor muscle tone (hypotonia) with no other related health problems. More severely affected people have problems in multiple body systems, often including severe brain dysfunction (encephalomyopathy). Approximately one-quarter of individuals with cytochrome c oxidase deficiency have a type of heart disease that enlarges and weakens the heart muscle (hypertrophic cardiomyopathy). Another possible feature of this condition is an enlarged liver (hepatomegaly), which may lead to liver failure. Most individuals with cytochrome c oxidase deficiency have a buildup of a chemical called lactic acid in the body (lactic acidosis), which can cause nausea and an irregular heart rate, and can be life-threatening.

Cytochrome c oxidase deficiency is a genetic condition that can affect several parts of the body, including the muscles used for movement (skeletal muscles), the heart, the brain, or the liver. Signs and symptoms of cytochrome c oxidase deficiency usually begin before age 2 but can appear later in mildly affected individuals.  https://medlineplus.gov/genetics/condition/cytochrome-c-oxidase-deficiency

Clinical features

From HPO
Hypertrophic cardiomyopathy
MedGen UID:
2881
Concept ID:
C0007194
Disease or Syndrome
Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality.
Cardiac arrest
MedGen UID:
5456
Concept ID:
C0018790
Finding
An abrupt loss of heart function.
Myofiber disarray
MedGen UID:
1615672
Concept ID:
C3671015
Finding
A nonparallel arrangement of cardiac myocytes.
Hepatomegaly
MedGen UID:
42428
Concept ID:
C0019209
Finding
Abnormally increased size of the liver.
Feeding difficulties
MedGen UID:
65429
Concept ID:
C0232466
Finding
Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.
Gliosis
MedGen UID:
4899
Concept ID:
C0017639
Pathologic Function
Gliosis is the focal proliferation of glial cells in the central nervous system.
Lethargy
MedGen UID:
7310
Concept ID:
C0023380
Sign or Symptom
A state of disinterest, listlessness, and indifference, resulting in difficulty performing simple tasks or concentrating.
Cerebral atrophy
MedGen UID:
116012
Concept ID:
C0235946
Disease or Syndrome
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
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.
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 dystonia
MedGen UID:
152944
Concept ID:
C0751093
Sign or Symptom
A type of dystonia (abnormally increased muscular tone causing fixed abnormal postures) that affects muscles of the limbs.
Sensorimotor neuropathy
MedGen UID:
207266
Concept ID:
C1112256
Disease or Syndrome
Increased CSF lactate
MedGen UID:
257904
Concept ID:
C1167918
Finding
Increased concentration of lactate in the cerebrospinal fluid.
Neuronal loss in central nervous system
MedGen UID:
342515
Concept ID:
C1850496
Finding
Neuronal loss in basal ganglia
MedGen UID:
413431
Concept ID:
C2750913
Finding
A reduction in the number of nerve cells in the basal ganglia.
Basal ganglia gliosis
MedGen UID:
416417
Concept ID:
C2750915
Finding
Focal proliferation of glial cells in the basal ganglia.
Focal cortical dysplasia
MedGen UID:
853938
Concept ID:
C2938983
Congenital Abnormality
A type of malformation of cortical development that primarily affects areas of neocortex. It can be identified on conventional magnetic resonance imaging as focal cortical thickening, abnormal gyration, and blurring between gray and white matter, often associated with clusters of heterotopic neurons.
Ventriculomegaly
MedGen UID:
480553
Concept ID:
C3278923
Finding
An increase in size of the ventricular system of the brain.
Brain atrophy
MedGen UID:
1643639
Concept ID:
C4551584
Disease or Syndrome
Partial or complete wasting (loss) of brain tissue that was once present.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Myopathy
MedGen UID:
10135
Concept ID:
C0026848
Disease or Syndrome
A disorder of muscle unrelated to impairment of innervation or neuromuscular junction.
Dolichocephaly
MedGen UID:
65142
Concept ID:
C0221358
Congenital Abnormality
An abnormality of skull shape characterized by a increased anterior-posterior diameter, i.e., an increased antero-posterior dimension of the skull. Cephalic index less than 76%. Alternatively, an apparently increased antero-posterior length of the head compared to width. Often due to premature closure of the sagittal suture.
Increased variability in muscle fiber diameter
MedGen UID:
336019
Concept ID:
C1843700
Finding
An abnormally high degree of muscle fiber size variation. This phenotypic feature can be observed upon muscle biopsy.
Irregular respiration
MedGen UID:
452504
Concept ID:
C0425492
Finding
Uneven rhythm of breathing.
Respiratory distress
MedGen UID:
96907
Concept ID:
C0476273
Sign or Symptom
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.
Inspiratory stridor
MedGen UID:
146165
Concept ID:
C0677600
Sign or Symptom
Inspiratory stridor is a high pitched sound upon inspiration that is generally related to laryngeal abnormalities.
Lactic acidosis
MedGen UID:
1717
Concept ID:
C0001125
Disease or Syndrome
An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids.
Increased circulating lactate concentration
MedGen UID:
332209
Concept ID:
C1836440
Finding
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).
Increased serum pyruvate
MedGen UID:
376596
Concept ID:
C1849488
Finding
An increased concentration of pyruvate in the blood.
Elevated lactate:pyruvate ratio
MedGen UID:
1717835
Concept ID:
C5397670
Finding
An abnormal increase in the molar ratio of lactate to pyruvate in the blood circulation.
High palate
MedGen UID:
66814
Concept ID:
C0240635
Congenital Abnormality
Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective).
Depressed nasal bridge
MedGen UID:
373112
Concept ID:
C1836542
Finding
Posterior positioning of the nasal root in relation to the overall facial profile for age.
Hypoplastic toenails
MedGen UID:
332409
Concept ID:
C1837279
Finding
Underdevelopment of the toenail.
Exotropia
MedGen UID:
4613
Concept ID:
C0015310
Disease or Syndrome
A form of strabismus with one or both eyes deviated outward.
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.
Limited extraocular movements
MedGen UID:
388060
Concept ID:
C1858427
Finding
Limited mobility of the eye within its socket.
Decreased activity of mitochondrial complex IV
MedGen UID:
866520
Concept ID:
C4020800
Finding
A reduction in the activity of the mitochondrial respiratory chain complex IV, which is part of the electron transport chain in mitochondria.

Supplemental Content

Recent activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...