What are the symptoms of mitochondrial disease?

With the advancement of modern science and technology, more and more diseases are diagnosed and treated. Among them, the number of diseases involving human genes has increased significantly. This is related to the destruction of the environment in which people live. Genetic diseases will also have an impact on future generations. For example, mitochondrial disease is a common modern disease. Let’s take a look at the symptoms of mitochondrial disease.

The diagnosis of mitochondrial myopathy relies on typical clinical symptoms: extreme intolerance of fatigue in the proximal limbs, short stature and sensorineural hearing loss, accompanied by clinical characteristics of various subtypes; increased serum lactate and pyruvate and the findings of RRF, mtDNA deletion or point mutation in muscle biopsy. CT or MRI examinations of patients with mitochondrial encephalomyopathy may reveal leukoencephalopathy, basal ganglia calcification, encephalomalacia, brain atrophy, and ventricular enlargement.

1. Mitochondrial myopathy usually begins at the age of 20. The clinical characteristics are that the skeletal muscles are extremely intolerant to fatigue, fatigue after mild activity, often accompanied by muscle soreness and tenderness, and muscle atrophy is rare. It is easily misdiagnosed as polymyositis, myasthenia gravis and progressive muscular dystrophy.

2. Mitochondrial encephalomyopathy includes:

(1) Chronic progressive extraocular ophthalmoplegia (CPEO) usually begins in childhood. The first symptom is ptosis, which slowly progresses to paralysis of all extraocular muscles, ocular movement disorders, symmetrical involvement of bilateral extraocular muscles, and diplopia is uncommon. Some patients have weakness of the pharyngeal muscles and limb muscles.

(2) Keams-Sayre syndrome (KSS): The disease begins before the age of 20 and progresses rapidly, manifesting as a triad of symptoms: CPEO, retinitis pigmentosa, and heart block. Other neurological abnormalities include cerebellar ataxia, increased cerebrospinal fluid (CSF) protein, sensorineural hearing loss, and mental retardation.

(3) Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome begins before the age of 40, with more cases occurring in childhood. Symptoms include sudden stroke-like attacks, such as hemiplegia, hemianopsia or cortical blindness, recurrent epileptic seizures, migraines and vomiting, and the condition gradually worsens.

(4) Myoclonic epilepsy with muscle fragmented red fibers (MERRF) syndrome usually occurs in childhood and is characterized by myoclonic epilepsy, cerebellar ataxia, and proximal limb weakness, and may be accompanied by multiple symmetrical lipomas.