This is a rare multiorgan disorder caused by alterations in the DNA of mitochondria. Mitochondria are small cellular organelles which are responsible for providing energy for cells to function.
Most patients have symptoms at birth with anemia and metabolic dysfunctions affecting the balance of electrolytes. Infants have difficulty fighting infections and evidence of liver and kidney malfunction. Scarring in these organs may lead to their failure and many infants do not survive beyond the first year or two of life. Failure to thrive, gastrointestinal difficulties with chronic diarrhea and fatty stools are common. Others who live to adulthood can experience muscular weakness. There may be drooping of the eyelids and difficulty moving the eyes.
Mutations in the DNA of mitochondria are transmitted only by mothers since sperm do not transmit these organelles. The clinical manifestations are highly variable with some patients having severe disease in early childhood while those who live to adulthood experience mainly muscle weakness.
The diagnosis requires a multidisciplinary team of specialists such as hematologists, pediatricians, and gastroenterologists. The prognosis is always guarded and patients require lifelong monitoring with acute intervention for infections and metabolic alterations. Many infants require blood transfusions early in life.