||Alpers’syndrome is a mitochondrial disease that is part of a larger group of conditions collectively known as mitochondrial DNA depletion disorders. It is most often caused by mistakes in the DNA of a gene called POLG and is part of a spectrum of POLG-related diseases. The major clinical features associated with Alpers’ syndrome are seizures, liver dysfunction, dementia, spasticity, blindness, and cerebral degeneration.
|Mitochondrial DNA Depletion Syndrome (MDDS)
||(1) Myopathy, with onset usually in infancy (floppy baby syndrome) or childhood (muscular dystrophy-like presentation). (2) Hepatocerebral syndrome, defined above as a combination of brain and liver dysfunctions. They are progressive disorders often fatal in childhood and for which no specific or effective therapy is available.
||Leigh syndrome (also known as Leigh disease) is a mitochondrial disease that usually affects young children. It is a severe neurological condition that typically affects the development of movement, posture, and mental abilities. Symptoms: Psychomotor regression (loss of acquired skills), abnormal respiration, vomiting, seizures, hypotonia, nystagmus (oscillation of the eyeballs), poor reflexes, eating and swallowing difficulties, ataxia, dystonia (abnormal posturing of the limbs). There is no cure for Leigh syndrome.
|Kearns-Sayre Syndrome (KSS)
||KSS is a progressive multi-system disease. it is usually caused by a single large deletion of mtDNA. Patients with KSS may have these problems, such as deafness, degeneration of the retina, dementia, kidney dysfunction, and muscle weakness. Endocrine abnormalities including growth retardation, short stature, diabetes, and deficiency of parathyroid hormone may also occur. There is no cure for KSS.
|Leber Hereditary Optic Neuropathy (LHON)
||LHON presents as blindness and is often associated with a cardiac conduction abnormality known as a pre-excitation syndrome or Wolff-Parkinson White syndrome. LHON is more common in men than in women and is usually caused by point mutations in mitochondrial DNA.
||(1) Encephalomyopathy, mental retardation, exercise intolerance, ragged-red fibers, and recurrent myoglobinuria (dark brown urine). (2) Isolated myopathy with ragged red fibers and excessive fat droplets. (3) Infantile multisystem diseases often involve brain and kidney. (4) Cerebellar ataxia (severe incoordination) and cerebellar atrophy.
|Mitochondrial Encephalopathy Lactic Acidosis with Stroke-like Episodes ( MELAS)
||MELAS is a progressive neurodegenerative disorder. The symptoms of MELAS are stroke-like episodes with focal neurological deficits, short stature, seizures, deafness, recurrent headaches, cognitive regression, diabetes, cardiopathy, gastrointestinal dysmotility, peripheral neuropathy. The most common cause is the point mutation of mitochondrial DNA. There is no cure or specific treatment for MELAS.