At 8 months old, Mikey Tighe suffered an unexplained seizure but recovered. Over the next two years, the San Diego boy “got every kind of test imaginable,” said his mother, Grace. “Everything came back negative,” reported the San Diego Union-Tribune in 2008.
Mikey was eventually diagnosed with Leigh’s syndrome, one of a diverse group of disorders that fall under the broad classification of mitochondrial disease (MD). It’s an inherited condition, the result of a defect or mutation in Mikey’s mitochondria – the tiny organelles found in every nucleated cell in the human body.
Children like Mikey now have some hope. In September 2009, researchers at Oregon Health and Science University published a study in Nature of a new kind of genetic therapy that’s meant to keep mitochondrial diseases from getting passed down from mother to child. The procedure uses techniques drawn from cloning. Working with rhesus macaque monkeys, researchers successfully substituted healthy donor mitochondria in place of a female’s defective genes. This allowed her to pass on her DNA to her baby, without passing on the defective mitochondria.