MELAS syndrome

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes – abbreviated to MELAS – is one of the family of mitochondrial cytopathies, which also include MERRF, and Leber's hereditary optic neuropathy. It was first characterized under this name in 1984. A feature of these diseases is that they are caused by defects in the mitochondrial genome which is inherited purely from the female parent. However, it is important to know that some of the proteins essential to normal mitochondrial function are produced by the nuclear genome, and are subsequently transported to the mitochondria for use. As such, mutations in these proteins can result in mitochondrial disorders, but can be inherited from both male and female parent in the typical fashion. The disease can manifest in both sexes.