线粒体疾病

线粒体疾病的症状是什么？

由于线粒体在人体的每个细胞中，因此线粒体疾病会影响许多不同的身体系统，并在不同组合中引起各种症状。这可以使他们具有挑战性地诊断。

The parts of the body that tend to be most affected are those that need the most energy, such as the heart, brain, muscles and gastrointestinal tract. Symptoms can range from fatigue and exercise intolerance to hearing loss, seizures, strokes, heart failure, diabetes and kidney failure. A large majority but not all children with mitochondrial disorders have developmental delay.

Depending on the severity of the disorder, symptoms can appear at birth or they may not appear until adulthood. In some children, mitochondrial disease progresses quickly and can be severe. In others, it can be stable and well-managed for many years. Sometimes symptoms begin suddenly, triggered by another illness.

What causes mitochondrial disease

线粒体是人体所有细胞的“发电厂”，产生了身体需要发挥作用的能量。他们还参与了代谢，帮助我们的细胞建立，分解和回收所需的化合物。

In mitochondrial disorders, the mitochondria’s ability to do these jobs is impaired because of a genetic mutation — a “mistake” in the DNA. We all have two types of DNA in our bodies. The nuclear DNA (usually just called “DNA”) is found in the cell's nucleus and is inherited from both our mother and father. Mitochondria also have DNA, inherited from mothers. Because both types of DNA are responsible for the structure and function of the mitochondria, mutations in either can cause mitochondrial disorders. Mutations can be inherited from parents or can happen for the first time in a child (so-calledde novo突变）。

Inherited mutations in the mitochondrial DNA come from the mother. Mutations in nuclear DNA usually are recessive, meaning that one copy of the mutation comes from each parent. In this case, the parents are just carriers and do not have mitochondrial disease themselves. This also explains why some people with a mitochondrial disorder have a family history of the disorder, while others are the only one in their family to be affected.

For more on mitochondrial disease, visit our常见问题页面.

线粒体疾病诊断?

Becausesymptoms如此多样化，影响体内多个器官，诊断线粒体疾病可能具有挑战性。有时，其他不涉及线粒体的疾病被错误诊断为线粒体疾病。情况也恰恰相反：有时真正患有线粒体疾病的人被诊断为其他东西。

Many symptoms of mitochondrial disease, such as不壮成长, short stature, poor stamina,developmental delay,seizures, poor muscle tone, vomiting, severe便秘, or腹泻，还有多种其他原因。因此，它通常不是一个症状，而是两种，三个或更多不同的症状的组合，导致临床医生怀疑线粒体疾病。

Genetic testing is the most reliable way to diagnose and categorize a mitochondrial disorder. We may recommend genetic testing for your child (and sometimes for parents too) if any of these symptoms are present:

• developmental delay with involvement of other organs
• dardiomyopathy（心肌疾病）或无法解释的心脏障碍，或心脏中的电信号受损
• 当存在其他症状时，血液或脑脊液中的乳酸水平高
• certain abnormal findings on brain imaging
• ophthalmoplegia (impaired eye movement) or ptosis (drooping upper eyelid)
• hearing loss
• 严重的胃肠道不动障碍（肠道中的弱或肌肉收缩）或肠道伪腹（肠梗阻）（肠梗阻是由于肠道无法将食物推开而引起的）
• 在疾病环境中的重大发展回归

Genetic testing often begins with analyzing the mitochondrial DNA and, if results are negative, testing the nuclear DNA for genes known to be involved in mitochondrial disease. If these tests come up negative, the child’s nuclear DNA may need to be completely analyzed through whole exome sequencing (this is similar to whole genome sequencing, but analyzes just the genes that code for proteins).

The type and depth of genetic testing we recommend will depend on the child’s symptoms and how strongly we suspect mitochondrial disease. Unfortunately, at this writing, extensive genetic testing is not always covered by insurance. If you or your child is in need of testing, we will work with your insurance companies to help with the process of approval.

其他非遗传测试也有助于诊断线粒体疾病。他们包括：

• biochemical tests on urine, blood and spinal fluid
• 肌肉活检检查线粒体和测试酶水平
• magnetic resonance imaging (MRI)of the brain and spine

如果怀疑或确定线粒体疾病，我们可能会向您的孩子转介您的孩子进行进一步的测试和咨询。测试取决于症状，可能包括：

• echocardiogram
• electrocardiogram (EKG)
• eye examinations
• hearing tests

Managing your child's condition

虽然线粒体疾病无法治愈，但当症状被发现并提早解决时，孩子通常会做得更好。您的孩子将受到仔细的遵循，并筛查与线粒体疾病有关的各种疾病，例如心脏，视力和听力问题。通常可以通过保持良好的一般健康来缓解症状，包括仔细注意营养以及避免感染和脱水。

Exercise is one of the few proven methods for improving mitochondrial functioning and can help preserve your child’s strength and endurance. Exercise regimens should be supervised, should build up very gradually in intensity and should be suspended during illness.

线粒体疾病有哪些治疗选择？

目前,补充维生素和mainstay of treatment for mitochondrial disorders. They are thought to help mitochondria produce energy and reduce accumulation of toxic compounds inside cells. These supplements and cofactors are sometimes given together in “cocktails.” At present, the compounds that have been most well tested include coenzyme Q10 and creatine, but we also use a great variety of other supplements.

Regimens for specific mitochondrial disorders may include compounds that are deficient because of the disease, such as arginine (in MELAS) and folinic acid (in Kearns-Sayre syndrome). At Boston Children’s, we are testing dichloroacetate (DCA), which counters the high levels of lactic acid found in some mitochondrial disorders. In certain disorders, we may prescribe a special diet.

支持ive care

由于线粒体疾病的儿童往往对感冒和发烧（感冒）造成的压力非常敏感，因此您的临床医生有时会在儿童生病时开出其他支持疗法。这些可以包括维生素，辅助因子，可能发生的生化失衡的药物，含有电解质的饮料，有时是静脉内（IV）水合和IV抗生素。在某些情况下，您的孩子可能需要在医院接受监测。

Children with mitochondrial disease also are known to be sensitive to a variety of drugs, as well as anesthetics used for surgical procedures.