What is Miyoshi myopathy?
Miyoshi myopathy is a severe inherited disease mainly characterized by weakness in the distal lower extremity posterior compartment (gastrocnemius and soleus muscles) and is associated with difficulties in standing on tip toes. The age of onset is adult.
Miyoshi myopathy follows an autosomal recessive pattern of inheritance. A couple is at risk of having affected offspring only when both members are carriers of the disease. When both members are carriers, the risk of having an affected child is 1 out of every 4 children.
What is the next step if I’m a carrier of Miyoshi myopathy?
If you are found to be a carrier of Miyoshi myopathy, it is important that your partner be tested for the same genetic disorder.
What if my partner is not a carrier?
If your partner’s test for Miyoshi myopathy is negative, the chance to have an affected child is low. However there is currently no test able to detect all existing mutations, so there is always a residual risk that the person who has done the test is a carrier of other less frequent mutations.
What if both me and my partner are carriers of Miyoshi myopathy?
When both parents are carriers of Miyoshi myopathy, the probability of having a child with this disease is 25%.
We recommend that you discuss your results with your doctor or genetic counselor in order to know more about reproductive options.