by Assunta Ginanneschi
This blog post tells the story of Noemi B.* and Filamin C myopathy. Noemi is a friend I met via a social networking site. Though we originally met to get practice speaking each other’s language, we soon became good friends. We met quite regularly for travels around Europe or just shopping and a cup of coffee. It never occurred to me that she had a rare disease, let alone a debilitating one. Then, one day while hiking in the mountains, she suddenly got very tired. I couldn’t imagine how she could get so tired so quickly. That was when she told me she has a rare disease: Filamin C myopathy. I never heard of it before and actually it’s so rare that it wasn’t yet in the Checkorphan database, though thanks to Noemi it is now.
In Noemi’s case, the genetic mutation causes a dominant and autosomal disorder, meaning that the gene in question is located on one of the numbered, or non-sex, chromosomes, and that a single copy of the disease-associated mutation is enough to cause the disease.
Filamin C is a type of muscle protein found in skeletal and cardiac muscle tissue. Filamin C myopathy therefore primarily affects skeletal muscles, the muscles that the body uses for movement.
Muscle weakness begins the furthest from the heart, slowly progressing to the inability to walk or grasp things, then to respiratory weakness due to inability to expand the lungs, and cardiac abnormalities. For a more detailed, scientific description, click here.
Filamin C myopathy is a very rare disease indeed. There are just a few a dozen cases in the medical literature, and it was just recently that the symptoms were directly related to a genetic cause.
Interestingly, distribution appears random, occurring in many different ethnicities and population distributions. For example, cases have been found in a large German family, in 18 members of a single Macedonian family, and in three members of a Chinese family. It has been found also in a large Australian family and a smaller Italian one.
My friend’s father has also been affected, and the disease has progressed to the point where he is in a wheelchair. Since filamin C myopathy is hereditary, it was important that Noemi got tested, understood potential life-threatening circumstances and got appropriate counseling to make necessary preparations. Diagnosis is made through a genetic test. Unfortunately, Noemi’s test came back positive. And that was when her race against time began.
At the moment, her therapy is limited to symptomatic treatment. The physicians recommend that she perform regular aerobic training and to try creatine supplementation, since this has proven to be safe and beneficial in various muscle diseases.
Besides creatine, I wonder what else she could try, maybe some other empowerment drugs or biochemicals (like EPO or L-Carnitine)?
Noemi gave me a nice article to read, that explains the matter in detail. Dr. Kley suggests a new therapeutic strategy: prevent the protein aggregation via early induction of chaperones or specific E3 ligases. Put in other words, the muscle degradation occurs only in the fibers harboring protein aggregates, so the idea is to hinder the aggregations using specific enzymes. What do the experts think about that?
Also, work has begun on stem cell therapy in the treatment of myopathies and Duchenne muscular dystrophy . The question now is which approaches (pharmacological, stem cell, etc.) show the most promise for effective therapies? Why?
The Filamin C myopathy is so rare that currently there are no specific advocacy organizations, but the patients can address muscular dystrophy associations.
I know I’ve got a lot of questions, but if we could get answers just to one of them it would be great for Noemi! At the time of writing, my friend is in her early 30s, so there is some time left to do something. Thanks guys, also on Noemi’s behalf.
*Name changed to protect the patient’s identity.
Filamin C-related myopathies: pathology and mechanisms, Acta Neuropathologica 2013 Jan;125(1):33-46.
Myofibrillar myopathy by NORD National Organization for Rare Disorders