Rare Endocrinology News
Disease Profile
Mitochondrial complex II deficiency
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
<1 >
Age of onset
Neonatal
ICD-10
G71.3
Inheritance
Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.
Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.
X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.
Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.
Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.
Not applicable
Other names (AKA)
Complex 2 mitochondrial respiratory chain deficiency; Succinate CoQ reductase deficiency; Mitochondrial respiratory chain complex II deficiency;
Categories
Congenital and Genetic Diseases; Metabolic disorders; Nervous System Diseases
Summary
Complex II deficiency is a
Symptoms
The signs and symptoms of mitochondrial complex II deficiency can vary greatly from severe life-threatening symptoms in infancy to muscle disease beginning in adulthood.[1] Many factors affect symptom and symptom severity, including what
Much of what we know today about the signs and symptoms of complex II deficiency are based on articles which describe individual patients. Due to the rarity of this condition and the complexity of its cause, it is very difficult to predict how a person will be affected. We strongly recommend that you work with your or your child’s healthcare provider to learn more about how the deficiency is affecting your or your child’s health. In the meantime, we have summarized symptoms of complex II deficiency which have been described in case reports:
Inheriting two SDHA gene mutations has caused myoclonic seizures and Leigh’s
Inheriting two SDHB gene mutations can cause leukodystrophy.[2] Leukodystrophies affect the
Inheriting two SDHAF1 gene mutations can cause severe progressive leukoencephalopathy beginning in infancy. Leukoencephalopathy refers to the degeneration of the white matter of the brain. It is usually diagnosed by
Inheriting two SDHD gene mutations can cause progressive loss of mental and movement abilities (psychomotor retardation), and
Complex II deficiency has also been described in association with dilated cardiomyopathy (and heart failure in childhood),[4] hemolytic uremic syndrome and rhabdomyolysis,
Case reports have also demonstrated that people who have only a single mutation in one of these genes may also be at risk for health problems:
Having one SDHA gene mutation caused optic atrophy,
Having one mutation in the SDHA, SDHB, SDHC, SDHAF2, or SDHD gene can cause an increased risk for paragangliomas and/or pheochromocytomas.[1]
This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.
Medical Terms | Other Names |
Learn More:
HPO ID
|
---|---|---|
30%-79% of people have these symptoms | ||
Abnormal left ventricular function | 0005162 | |
Babinski sign | 0003487 | |
Loss of developmental milestones
Mental deterioration in childhood
[ more ] |
0002376 | |
Distal amyotrophy |
Distal muscle wasting
|
0003693 |
Easy fatigability | 0003388 | |
Generalized muscle weakness | 0003324 | |
Generalized myoclonic seizure | 0002123 | |
Hyperactive deep tendon reflexes | 0006801 | |
Hyperactive patellar reflex |
Overactive knee reflex
|
0007083 |
Hyperreflexia in upper limbs | 0007350 | |
Hypertrophic |
Enlarged and thickened heart muscle
|
0001639 |
Left ventricular hypertrophy | 0001712 | |
Motor delay | 0001270 | |
Motor deterioration |
Progressive degeneration of movement
|
0002333 |
Progressive psychomotor deterioration | 0007272 | |
Proximal muscle weakness |
Weakness in muscles of upper arms and upper legs
|
0003701 |
Severe |
Dwarfism
Proportionate dwarfism
Short stature, severe
[ more ] |
0003510 |
Skeletal myopathy | 0003756 | |
Weight loss | 0001824 | |
5%-29% of people have these symptoms | ||
Abnormal atrioventricular conduction | 0005150 | |
Ataxia | 0001251 | |
Expressive language delay | 0002474 | |
Feeding difficulties in infancy | 0008872 | |
Focal myoclonic seizure | 0011166 | |
Frequent falls | 0002359 | |
Generalized |
Decreased muscle tone
Low muscle tone
[ more ] |
0001290 |
Intrauterine growth retardation |
Prenatal growth deficiency
Prenatal growth retardation
[ more ] |
0001511 |
Irritability |
Irritable
|
0000737 |
Knee flexion |
0006380 | |
Lower limb hypertonia | 0006895 | |
Mild |
0040196 | |
Moderate global |
0011343 | |
Noncompaction cardiomyopathy | 0012817 | |
Spastic paraparesis | 0002313 | |
Spastic tetraparesis | 0001285 | |
1%-4% of people have these symptoms | ||
Blindness | 0000618 | |
Dementia |
Dementia, progressive
Progressive dementia
[ more ] |
0000726 |
External ophthalmoplegia |
Paralysis or weakness of muscles within or surrounding outer part of eye
|
0000544 |
Loss of ability to walk | 0006957 | |
Involuntary, rapid, rhythmic eye movements
|
0000639 | |
Pigmentary retinopathy | 0000580 | |
Poor head control | 0002421 | |
Vesicoureteral reflux | 0000076 | |
Percent of people who have these symptoms is not available through HPO | ||
Abnormal |
0008316 | |
0000007 | ||
Cognitive impairment |
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment
[ more ] |
0100543 |
Decreased activity of mitochondrial complex II | 0008314 | |
Dilated cardiomyopathy |
Stretched and thinned heart muscle
|
0001644 |
0001332 | ||
Exercise intolerance |
Decreased ability to exercise
Inability to exercise
[ more ] DiagnosisMaking a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional. Testing Resources
Treatment Treatment options for complex II deficiency may be similar to those for other
OrganizationsSupport and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD. Organizations Supporting this Disease
Organizations Providing General Support
Learn moreThese resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional. In-Depth Information
Selected Full-Text Journal Articles
References
Rare Endocrinology News |