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| News |
Indo-US
Meeting on
9-10, Dec
2011
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| FOR
PATIENTS |
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Mitochondria
A mitochondrion (singular of mitochondria) is part
of every cell in the body that contains genetic
material, other than nucleus. Mitochondria are
responsible for processing oxygen and converting
substances from the foods we eat into energy in the
form of adenosine triphosphate (ATP) for essential
cell functions.
Mitochondrial
disorders
The process of converting food and oxygen (fuel)
into energy requires hundreds of chemical
reactions, and each chemical reaction must run
almost perfectly in order to have a continuous
supply of energy. When one or more components of
these chemical reactions do not run perfectly,
there is an energy crisis, and the cells cannot
function normally. As a result, the incompletely
burned food might accumulate as poison inside the
body.
This poison can stop other chemical reactions
that are important for the cells to survive,
making the energy crisis even worse. In addition,
these poisons can act as free radicals (reactive
substances that readily form harmful compounds
with other molecules) that can damage the
mitochondria over time, causing the mitochondrial
disorders. There are about 40 mitochondrial
disorders, which affect multiple organs of our
body. |
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Symptoms of
mitochondrial disorders
The types of mitochondrial diseases are categorized
according to the organ systems affected and symptoms
present. Mitochondrial diseases might affect the
cells of the brain, nerves (including the nerves to
the stomach and intestines), muscles, kidneys,
heart, liver, eyes, ears, or pancreas. In some
patients, only one organ is affected, while in other
patients all the organs are involved. Depending on
how severe the mitochondrial disorder is, the
illness can range in severity from mild to fatal.
Depending on which cells of the body are affected,
symptoms might include: |
- Poor growth
- Loss of muscle coordination, muscle weakness
- Visual and/or hearing problems
- Developmental delays, learning disabilities
- Mental retardation
- Heart, liver, or kidney disease
- Gastrointestinal disorders, severe
constipation
- Respiratory disorders
- Diabetes
- Increased risk of infection
- Neurological problems, seizures
- Thyroid dysfunction
- Dementia (mental disorder characterized by
confusion, disorientation, and memory loss)
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Prevalence
of mitochondrial disorders
Current estimates place the incidence of
mitochondrial disorder at about 1 in 2000 to 1 in
5000 live births. In adults, many diseases of
aging have been found to have defects of
mitochondrial function. These include, but are not
limited to, type 2 diabetes, Parkinson's disease,
atherosclerotic heart disease, stroke, Alzheimer's
disease, and cancer. In addition, many medicines
can injure the mitochondria.
Diagnosis of
mitochondrial disorders
Diagnosis of mitochondrial disease can be invasive,
expensive, time-consuming, and labor-intensive.
Therefore, evaluation is not taken lightly. Doctors
experienced in diagnosing and treating these
diseases will take either a step-wise approach to
diagnosis or, in some centers, the evaluation takes
place over a few days. The evaluation includes a
combination of clinical observations and laboratory
tests.
Under ideal circumstances, the evaluation will
produce an answer. However, even after a multiple
evaluations, the doctor might not be able to confirm
a specific diagnosis or put a name to the disorder.
In many cases, however, the physician will be able
to identify which patient does and doesn't have
mitochondrial disease.
Mitochondrial disease is diagnosed by
- Evaluating the patient's family history
- Performing a complete physical examination
- Performing a neurological examination
- Performing a metabolic examination that
includes blood, urine, and optional cerebral
spinal fluid tests
- Performing other tests, depending on the
patient's specific condition and needs. These
tests might include:
- Magnetic resonance imaging (MRI) or scan
(MRS) if neurological symptoms are present
- Retinal exam or electroretinogram if
vision symptoms are present
- Electrocardiogram (EKG) or echocardiogram
if heart disease symptoms are present
- Audiogram or BAEP if hearing symptoms are
present
- Blood test to detect thyroid dysfunction
if thyroid problems are present.
- Blood test to perform genetic DNA testing
More invasive tests, such as a
skin or muscle biopsy, might be performed as needed
and recommended by your doctor. |
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Defined
mitochondrial disorders
Some of the defined mitochondrial diseases and
the disorders where mitochondrial defect is
confirmed include
Chronic Progressive External Ophthalmoplegia
(CPEO)
Diabetes Mellitus
Kearns Sayre Syndrome
Leber Hereditary Optic Neuropathy (LHON)
Mitochondrial Cardiomypathy
Mitochondrial myopathy
Mitochondrial Encephalomyopathy
Mitochondrial Encephalomyopathy, Lactic Acidosis,
and Stroke-like episodes (MELAS)
Myoclonic Epilepsy and Ragged Red Muscle Fibers
(MERRF)
Maternally Inherited Leigh Syndrome (MILS)
Neuropathy, Ataxia, and Retinitis
Pigmentosa(NARP)
Sensorineural Hearing Loss
Alzheimer's Disease |
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Treatment
of mitochondrial disorders
There are no cures for mitochondrial diseases, but
treatment can help reduce symptoms, or delay or
prevent the progression of the disease. Treatment is
individualized for each patient, as doctors
specializing in metabolic diseases have found that
every child and adult is "biochemically
different." That means that no two people will
respond to a particular treatment in a specific way,
even if they have the same disease.
- Certain vitamin and enzyme therapies,
along with occupational and physical therapy,
might be helpful for some patients.
Vitamins and supplements prescribed might
include:
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