A multinational study on motor function in early-onset FSHD
Jean K Mah1, Jia Feng2, Marni B Jacobs2
1From the University of Calgary (J.K.M.), Alberta Children's Hospital, Canada; Children's National Medical Center (J.F., M.B.J., C.L.C., L.M., M.T., A.C., Y.-W.C.), Washington, DC; Stanford University (T.D.), CA; Royal Children's Hospital (K.C., K.d.V., M.M.R.), Melbourne, Australia; Newcastle Upon Tyne Hospitals (M.G.), UK; University of Pittsburgh (P.R.C.) and the Department of Veteran Affairs Medical Center, PA; Children's Hospital at Westmead (R.W.), Sydney, Australia; Duke Medical Center (E.S.), Durham, NC; Washington University (A.M.C.), St. Louis, MO; University of California at Davis Medical Center (C.M.M.), Sacramento; University of Minnesota (P.K.), Minneapolis; Gothenburg University (M.T.), Queen Silvia Children's Hospital, Sweden; Carolinas Medical Center (A.H.), Charlotte, NC; and Therapeutic Research in Neuromuscular Disorders Solutions (L.P.M.), LLC, Kensington, MD. jkmah@ucalgary.ca.
Objectives:
To investigate motor function associations with age, sex, and D4Z4 repeats among participants with early-onset facioscapulohumeral muscular dystrophy (FSHD) type 1 as defined by weakness onset before 10 years of age.
Methods:
We collected standardized motor assessments, including manual muscle testing (MMT), quantitative muscle testing, functional motor evaluations, and clinical severity scores (CSSs), at 12 Cooperative International Neuromuscular Research Group centers. To measure associations, we used linear regression models adjusted for sex, evaluation age, age at onset of weakness, and D4Z4 repeats.
Results:
Among 52 participants (60% female, mean age 22.9 ± 14.7 years), weakness was most pronounced in the shoulder and abdominal musculature. Older enrollment age was associated with greater CSSs (p = 0.003). When adjusted for enrollment age, sex, and D4Z4 repeats, younger age at onset of facial weakness was associated with greater CSSs, slower velocities in timed function tests, and lower MMT scores (p < 0.05).
Conclusion:
Significant clinical variability was observed in early-onset FSHD. Earlier age at onset of facial weakness was associated with greater disease severity. Longitudinal assessments are needed to determine the rate of disease progression in this population.
Related Concept Videos
01:24Serum Studies: Renal Function Tests
00:46Motor Units
01:13Motor Units
Motor units come in different sizes, with smaller units...
01:20Motor Unit Stimulation
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
01:18Hierarchy of Motor Control
01:11Direct Motor Pathways
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and...