Myotonic muscular dystrophy (MMD) is the most common adult-onset form of muscular dystrophy (MD). The name refers to a symptom, myotonia — prolonged spasm or stiffening of muscles after use. The disease causes muscle weakness and also affects the central nervous system, heart, gastrointestinal tract, eyes, and hormone-producing glands. Symptoms include weakness of all muscle groups accompanied by delayed relaxation of muscles after contraction; areas affected early include face, feet, hands, and neck.
MMD is sometimes referred to as “Steinert’s Disease,” after the Germon doctor who originally described the disorder in 1909. It is found in both men and women, and it usually appears any time from early childhood to adulthood. In rare cases, it appears in newborns (congenital MMD). Generally, the earlier MMD1 begins, the more profound the symptoms tend to be. That’s the case with Jordan Gattis.
Jordan was diagnosed with MMD at birth, at which time his mother Jody was tested and also diagnosed. Jody was 29 at the time and had no serious symptoms, although she had pain in her hands since she was a little girl. She is now in her 50’s and still has minor issues, but the disease is starting to progress. She inherited the disease from her father who was diagnosed at age 60 after 20 years of symptons. He lived to be 72 and never lost the ability to walk on his own.
In most cases, daily living isn’t restricted for many years, yet most have a decreased life expectancy. The progression of MMD varies greatly among individuals, but in general, symptoms progress slowly, sometimes spanning 50 to 60 years.
The progression has varied greatly in the Gattis family. Jordan has been on a ventilator since he was 10 years old, has issues with his eyesight, and fatigues easily. Nonetheless, his arms have remained relatively strong. In contrast, his mother didn’t have very noticeable issues until her 50s starting with balance, eyesight issues and pain in her feet and legs. Her father, Jordan’s grandfather, was even older before having serious issues. Jody says the disease runs rampant in her family with 4 of her father’s 6 siblings all having adult onset Mytonic MD, and one of her cousins having 9 of 10 children with childhood onset of of Mytonic MD, showing only mild symptoms thus far. Unfortunately, when the disease was passed on to Jordan, it presented in a much more severe form than anyone else in the family with issues from birth, preventing Jordan from ever walking on his own.
The most common type of MMD1 — the “adult-onset” form — begins in adolescence or young adulthood, often with weakness in the muscles of the face, neck, fingers and ankles. When MMD1 begins earlier in life than adolescence — the congenital-onset and juvenile-onset forms of the disease — it may be quite different in progression from the adult-onset type. Children with congenital-onset MMD1, once they survive the crucial neonatal period of respiratory muscle weakness with the help of assisted ventilation, usually show improvements in motor and breathing functions over the first year or so. They may have cognitive impairment, delayed speech, difficulty eating and drinking and various other developmental delays. Most will learn to walk, but unfortunately, this was not the case with Jordan. He relies on a ventilator and a feeding tube, and cannot control his facial muscles, leaving his right eyelid shut and difficulty keeping his left eye open.
MMD2 is, in general, a milder disease than type 1. It does not appear to have a congenital-onset form and rarely begins in childhood. This is likely the type that Jordan’s grandfather and his siblings had. In contrast to type 1 MMD, the muscles affected first in MMD2 are the proximal muscles — those close to the center of the body — particularly those around the hips. However, some finger weakness may be seen early as well. The disorder progresses slowly, but mobility may be impaired early because of weakness of the large, weight-bearing muscles. MMD2 is quite rare, except in Germany and in people of German descent.
Because of the rareness of this type of MD, research is slow. Studies have focused on mice, and human trials are on the near horizon. While the Gattis family is anxious for any answers or treatment that might slow Jordan’s progression, they feel frustrated that there isn’t more progress. In the meantime, Jody wants to pursue ways to expand MD Awareness, with hopes that there will be more interest in helping others with Myotonic MD, especially her son Jordan.