Mitochondrial myopathies are conditions arising from dysfunction of the mitochondria Mitochondria Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive ribosomes, transfer RNAs; amino Acyl tRNA synthetases; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs. Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. The Cell: Organelles (the energy-producing structures) and are characterized by prominent muscular symptoms and accompanied by various symptoms from organs with high energy requirements. The organs disproportionately affected include the skeletal muscles Skeletal muscles A subtype of striated muscle, attached by tendons to the skeleton. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles. Muscle Tissue: Histology, brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification, and heart. Mitochondrial myopathies are caused by mutations in the nuclear DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure or mitochondrial DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure, which typically result in reduced production of energy needed by cells. Presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor can be an isolated myopathy Myopathy Dermatomyositis, encephalomyopathy, ophthalmoplegias, or a multisystem disease. Diagnosis involves in-depth medical and family history Family History Adult Health Maintenance, along with laboratory and genetic studies. On biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma, there is subsarcolemmal and intermyofibrillar proliferation of mitochondria Mitochondria Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive ribosomes, transfer RNAs; amino Acyl tRNA synthetases; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs. Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. The Cell: Organelles seen as “ragged-red fibers.” This condition indicates a compensatory response to energy failure. There is no definitive treatment. Management consists of physical therapy Physical Therapy Becker Muscular Dystrophy and a multidisciplinary approach in addressing accompanying symptoms.
Last updated: 29 Jan, 2022
Mitochondrial myopathies are diseases that arise from dysfunction of the mitochondria Mitochondria Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive ribosomes, transfer RNAs; amino Acyl tRNA synthetases; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs. Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. The Cell: Organelles (the energy-producing structures). These diseases are characterized by prominent muscular symptoms (such as muscle weakness) and accompanied by various symptoms from organs with high energy requirements.
Structure of a mitochondrion
Image: “Mitochondrion of the eukaryotic Eukaryotic Eukaryotes can be single-celled or multicellular organisms and include plants, animals, fungi, and protozoa. Eukaryotic cells contain a well-organized nucleus contained by a membrane, along with other membrane-bound organelles. Cell Types: Eukaryotic versus Prokaryotic cell” by Mariana Ruiz Villarreal. License: Public DomainSigns and symptoms correlate to organs or tissues affected:
Kearns-Sayre syndrome (KSS):
Patient with bilateral
ptosis
Ptosis
Cranial Nerve Palsies
Clinical features of myoclonic epilepsy Epilepsy Epilepsy is a chronic brain disorder marked by recurrent and unprovoked seizures. These seizures can be classified as focal or generalized and idiopathic or secondary to another condition. Clinical presentation correlates to the classification of the epileptic disorder. Epilepsy with ragged red fibers (MERRF) mutation Mutation Genetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations: hair thinning, bilateral ptosis Ptosis Cranial Nerve Palsies, facial diplegia with temporalis Temporalis A masticatory muscle whose action is closing the jaws; its posterior portion retracts the mandible. Jaw and Temporomandibular Joint: Anatomy muscle wasting Muscle Wasting Duchenne Muscular Dystrophy, jaw Jaw The jaw is made up of the mandible, which comprises the lower jaw, and the maxilla, which comprises the upper jaw. The mandible articulates with the temporal bone via the temporomandibular joint (TMJ). The 4 muscles of mastication produce the movements of the TMJ to ensure the efficient chewing of food. Jaw and Temporomandibular Joint: Anatomy weakness, neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess flexor muscle weakness, and neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess extensor muscle weakness
Image: “Clinical features of the MERRF mutation Mutation Genetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations” by Wellcome Trust Trust Confidence in or reliance on a person or thing. Conflict of Interest Centre for Mitochondrial Research Research Critical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws. Conflict of Interest, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne NE2 2HH, UK. License: CC BY 3.0Leber hereditary optic neuropathy Neuropathy Leprosy with disc hyperemia, retinal tortuosity, and swelling Swelling Inflammation of the peripapillary retinal nerve fiber layer
Image: “Acute fundal appearance in Leber hereditary optic neuropathy Neuropathy Leprosy” by Mitochondrial Research Research Critical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws. Conflict of Interest Group, The Medical School, Newcastle University, Newcastle upon Tyne, UK. License: CC BY 2.0Muscle
biopsy
Biopsy
Removal and pathologic examination of specimens from the living body.
Ewing Sarcoma in a patient with typical features of mitochondrial encephalomyopathy,
lactic acidosis
Lactic Acidosis
Oxazolidinones, and stroke-like episodes (MELAS):
Modified Gomori trichrome stain showing several ragged-red fibers (arrows)
Muscle biopsy of a patient with myoclonus and progressive cognitive decline:
Ragged-blue fibers noted on succinate dehydrogenase preparation