Etiology

More than 1 in 4,000 children born each year in the US will develop a mitochondrial disease by age 10. Because they are under-recognized, this figure may be grossly under-estimated. Most cases are inherited, the majority of which are probably through autosomal recessive inheritance (both parents contributing a defective gene). Another mode of transmission is maternal inheritance, which may be as common. There are other rarer modes of inheritance and even some sporadic cases in which the mutation is a new one. Males and females are equally affected.