Facioscapulohumeral muscular dystrophy, or FSHD, is among the most prevalent of the nine primary types of muscular dystrophy affecting adults and children. Muscular dystrophy describes a genetic, hereditary muscle disease that causes progressive muscle weakness. The term neuromuscular disease encompasses diseases that affect neurons (nerves) and muscles; thus, FSHD and other forms of muscular dystrophy are also described as neuromuscular diseases. The different forms of muscular dystrophy are alike in that they cause defects in the biochemical, physical and structural components of muscle, the death of muscle cells and tissue, and progressive and debilitating skeletal muscle weakness. However, with the exception of the Duchenne and Becker forms—which arise from different defects within the same dystrophin gene—each form of muscular dystrophy is a unique, distinct disease with a distinct genetic origin.
The name facioscapulohumeral derives from the muscle groups in which symptoms often first appear: facio – the muscles of the face; scapulo – the muscles of the shoulder blades (the scapulae); and humeral – the muscles of the upper arm (from humerus, the upper arm bone). Let me stress, however, that while weakness in these muscle groups may be the first to appear, the disease progresses to affect all skeletal muscle.
During an initial visit to a physician, facial weakness might appear as difficulty in keeping the eyes open or closed when the examining physician applies a minimal force, and a patient may find it difficult to whistle, blow up a balloon, or even to smile. Weakness in the trapezius muscle presents as a winging of the shoulder blade when the arm is held out forward and difficulty in raising the arms overhead. The biceps and triceps may be also be weak, although this may initially be dismissed as being within the range of variability in strength among different individuals.
Early symptoms of FSHD also include abdominal muscle weakness, which may appear as difficulty in doing sit-ups. The lower abdominal muscles are usually more affected than the upper muscles, giving rise to what is known as a positive Beevor’s sign, where the navel can be seen to move toward the head when the abdominal muscles are flexed during a sit-up. This results from asymmetric weakness in the abdominal muscles: the upper muscles contract with more force than the lower abdominal muscles. This particular sign is not observed in other neuromuscular disorders, and, therefore, it is an observation that can support a diagnosis of FSHD. The progressive loss of abdominal support affects posture, causing abdominal protuberance and an inward curvature of the lumbar spine (lordosis). Foot drop is also a relatively early consequence of FSHD and may cause the tip of the shoe to catch on the ground unexpectedly as the foot swings forward while walking. Foot drop can develop quite gradually, and individuals will unconsciously compensate by lifting the leg slightly higher as the foot swings forward. As a result, foot drop may be more apparent to a clinician than to the affected individual or a family member.
It’s important to emphasize here that the age of onset (or at least, the age at which symptoms are first noticed, and there may be a difference between the two), the rate of progression, and the severity of FSHD are highly variable. In the infantile form symptoms appear in early childhood, but symptoms may not appear until late adulthood. In some instances there may be a recognized history of physical difficulty (e.g., “dad always had difficulty raising his arms to work overhead, and so did I, and we just assumed that it was just something peculiar about our family)”, with a diagnosis coming only years later. As I indicated above, although muscles of the face, the shoulder blades, and upper arms may be the first in which weakness appears, the dystrophic process progresses to affect all skeletal muscles (arms, legs, hands, feet, trunk muscles). Some individuals may experience a more aggressive progression, exhibiting as adolescents or young teens with a profound loss of tone in facial muscles affecting the ability to speak or show expression. Weakness of the trunk and large leg muscles , cause an exaggerated lordosis and an awkward gait. In severe cases, extreme weakness develops in respiratory muscles, and this can lead to death due to respiratory failure.
At the other end of the spectrum are affected individuals who remain ambulatory throughout their lifetime, showing only a hint of the typical symptoms, e.g., a life-long difficulty in blowing up a balloon. The variability in disease severity contributes to the difficulty in pinning down a specific upper age limit for the onset of FSHD.
Quality of Life
From the time of first diagnosis, FSHD presents quality-of-life challenges. The initial diagnosis put a grey cloud over my outlook for the future. On the one hand, it didn’t seem to me there was that much wrong…so my shoulder blade stuck out when I raised my right arm and I couldn’t puff my cheeks and hold it tightly. I still played baseball, football, and basketball as well or better(yes, I had to add the “or better”) as most of my friends. But I do remember wondering about the future and how it would limit my options. After a few years, when the foot drop began and I would trip for “no reason” as my foot caught on the ground on the forward stroke, it occurred to me that I would probably be in a wheelchair by age 40. (As it turned out, I missed it by 20 years, and at age 60 it was a scooter, not a wheelchair.)
I played baseball in high school through my junior year, but withdrew after my running became inexpicably slow. I say inexplicably because I couldn’t understand why I was so slow. My legs seemed to be really strong, and I could lift all the weights on the leg-press machine. I only figured out later the reason I could run fast had nothing to do with my legs; it was my shoulders. In order to run fast you have to be albe to pump your arms at the same speed as your legs, moving them forward and back around a shoulder pivot point that remains fixed in place. The problem is that with FSHD the weak shoulder muscles allow the shoulder itself to move around, throwing the entire motion out of whack and limiting the rate of the entire process.
I was active guy and enjoyed a wide variety of sports. I watched these fall by the wayside year after year. I suppose the same thing happens during the normal aging process, but with FSHD it is accelerated. I was last able to run–and I don’t mean run well, but simple the act of propelling oneself forward with both feet off the ground such that you must support your wight with on leg as you land with each stride–in 1989. I remember the night I was walking my dogs, Bert and Lucy, in Sunnyvale California, and I discovered it. Now I also remember that last time I could walk–May 23, 2014, when I fell in an awkward manner that tore my left hamstring.
Something else that stands out in my memory, the need to look at the ground while walking. I have a vivid memory of my first trip to London, England. I was a doctoral student studying pharmacology at the University of Houston, and was attending a meeting of the British Pharmacological Society, held a University College London near Russell Square. While attending the meetings, it was typical to head to a local pub for lunch and to do the same at the end of the day. This was where all the really interesting scientific discussions took place. I hung out with my mentor, David Clarke, and a number of his well known colleages from academia and industry. That was great. But what I remember also was that as we walked the streets of London, rather than looking at each other and at the sights of the city, I had to focus on where each foot step was to be placed, lest I trip on a cobblestone or an irregularity in the sidewalk. I did eventually trip, tear a hole in my trousers, and scrape my right knee so that it bled through the material. For someone with FSHD, this is commonplace.
There are too many small details that come to mind, and it’s not critical that I mention them all. As the weakness progresses, the ability to contribute physically must be replaced with the satisfaction of knowing that others are usally willing to help. Of course, actually asking for help is another matter altogether, and there is often a sense of not wanting to become a burden. I have been blessed with a resilient disposition, and I don’t really let things get me down. One thing that I do miss is the ability to hug my wife and my daughter. I would like to have been able to be the one who would lift our little girl out of the back seat of the car and carry her to her room, tuck her it, and kiss her good night. By that time, however, I couldn’t lift her. Now I have two adorable grand kids, but I have never been able to lift or hold them, and I would love to do that. In addition, they can’t be left with their grandpa, not because he is untrustworthy, but I’m not able to actually provide the care they need at their age.
My reference to my daughter above reminds me that I must mention a very important issue that arises for individuals with FSHD. The inheritance pattern for FSHD is autosomal dominant (not linked to the X chromosome, therefore occurring equally in both genders), meaning that the offspring of a couple where one parent is affected have a 50% chance of inheriting the genetic condition for FSHD, and a child inheriting the genetic condition for FSHD has a 100% chance of developing FSHD.(*) Ava is technically my step daughter, not my biological daughter. I made the decision while in my 20s that, while I could handle FSHD, it was not something I wanted to pass on to a son or daughter. This is a very personal issue that each person with FSHD must face. For many women with FSHD there is an addition concern, that is, “will I be able physically to handle a pregnancy and childbirth.”
These comments primarily reflect my own perspective on the FSHD. I figure my FSHD represents sort of an average-case scenario. Some individuals are much less affected. But many are affected to a much greater extent than I am now or was during my youth. For these young individuals, FSHD places another really heavy challenge during the very critical years when all adolescents are developing their self image and are developing their identities among their peers. A disease that can rob a young person of their ability to communicate through facial expression and cues places on him or her a great burden during these formative years.
(*) I have used the term “genetic condition” rather than “gene” because the genetics of FSHD are unique, as will become clear when you read more about this in another post or page. In addition,due to the unique genetics of FSHD, there are multiple other factors that can determine how severely the disease FSHD is expressed or whether is is expressed at all.