Disease burden and functional outcomes in congenital myotonic dystrophy: A cross-sectional study.
Herein, we describe the disease burden and age-related changes of congenital-onset myotonic dystrophy (CDM) in childhood.



Children with CDM and age-matched controls aged 0 to 13 years were enrolled. Participants were divided into cohorts based on the following age groups: 0-2, 3-6, and 7-13 years. Each cohort received age-appropriate evaluations including functional testing, oral facial strength testing, neuropsychological testing, quality-of-life measurements, and ECG. Independent-samples t test or Wilcoxon 2-sample test was used to compare the differences between children with CDM and controls. Probability values less than 0.05 are reported as significant.



Forty-one participants with CDM and 29 healthy controls were enrolled. The 6-minute walk was significantly different between CDM (258.3 m [SD 176.0]) and control participants (568.2 m [SD 73.2]). The mean lip force strength was significantly different in CDM (2.1 N [SD 2.8)] compared to control participants (17.8 N [SD 7.6]). In participants with CDM, the mean IQ (65.8; SD 18.4) was 3 SDs below the mean compared to standardized norms. Measurements of grip strength, sleep quality, and quality of life were also significantly different. Strength measures (oral facial strength, grip strength, and 6-minute walk) correlated with each other but not with participant IQ.



This work identifies important phenotypes associated with CDM during childhood. Several measures of strength and function were significantly different between participants with CDM and controls and may be useful during future therapeutic trials.
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada. Nicholas.johnson@hsc.utah.edu.
Nicholas E
NE
Johnson
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Russell
R
Butterfield
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Kiera
K
Berggren
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Man
M
Hung
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Wei
W
Chen
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Deanna
D
DiBella
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Melissa
M
Dixon
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Heather
H
Hayes
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Evan
E
Pucillo
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Jerry
J
Bounsanga
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Chad
C
Heatwole
From the Departments of Neurology (N.E.J., R.B., K.B., D.D., M.D., E.P.), Orthopaedics (M.H., J.B.), and Physical Therapy (H.H.), and Division of Epidemiology (M.H., W.C.), The University of Utah, Salt Lake City; Department of Neurology (C.H.), The University of Rochester, NY; and Departments of Pediatrics, Clinical Neurological Sciences, and Epidemiology (C.C.), Western University, London, Canada.
Craig
C
Campbell
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D005152:Facial Muscles / Q000503:physiopathology; D005260:Female; D006225:Hand / Q000503:physiopathology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007360:Intelligence; D008046:Lip / Q000503:physiopathology; D008297:Male; D053580:Muscle Strength; D009223:Myotonic Dystrophy / Q000503:physiopathology* / Q000628:therapy; D011788:Quality of Life; D012890:Sleep; D016896:Treatment Outcome