Mitochondrial disease is an umbrella heading that covers a multitude of sub-types of very specific diseases and many others less well-defined. Specific subtypes include Leigh disease, MELAS, MERRF, CPEO all associated with a variety of mitochondrial gene mutations. There are a total of approximately 1500 different genes that regulate mitochondrial function. 37 of those genes are strictly maternally inherited. The remainder are inherited through both parents. In the pediatric population, 75% to 90% of mitochondria disease is inherited in an autosomal recessive fashion. As such, if the gene mutation is unknown in a specific pediatric patient, parents will often be given empiric recurrence risks of 25% for each and every subsequent pregnancy they consider. These numbers are, therefore, based on the fact that most of the genes that regulate mitochondrial functioning are inherited through both parents.Always remember, though, that if the gene mutation for you or your child is UNKNOWN your quoted recurrence risks are merely an educated guess and could be quite different than your actual risk.
Fran Kendall, M.D.
This post is not meant to be a recommendation or a substitute for professional advice and services rendered by qualified doctors, allied medical personnel, and other professional services. The responsibility for any use of this information, or for proper medical treatment, rests with you.