POMT2 mutation is known to cause Walker Warburg Syndrome and Muscle-Brain-Eye syndrome. Recently it has been connected to limb girdle muscular dystrophy (LGMD), a disorder characterized by muscle weakness and atrophy of the proximal muscles of the shoulder and pelvic girdles. LGMD is classified based on its inheritance pattern and genetic cause into more than 31 different types. LGMD with POMT2 mutations is a new phenotype - type 2N. Very few patients with the LGMD2N phenotype has been reported. In this study, the investigators examine five new cases with the LGMD phenotype. The primary aim is to examine the muscle involvement using MRI.
Study Type
OBSERVATIONAL
Enrollment
12
Copenhagen Neuromuscular Center, Rigshospitalet
Copenhagen, Denmark
MRI scan for qualitative analysis of muscle involvement
The MRI protocol include T1-weighted brain and whole body examination. Four cross-sectional slices at shoulder, lumbar back, thigh and calf are chosen for qualitative analysis using the grading scale from 1 to 4 developed by Mercuri et al. (2007) to evaluate the involvement of muscles by looking at the fat infiltration.
Time frame: One MRI scan per subject (exam lasts approximately 60 min.)
Muscle Biopsy
One muscle biopsy from each patient from the tibialis anterior muscle or the deltoid muscle will be analyzed for glycosylated α-dystroglycan, merosin and POMT2. (Concentration determined by standard biochemical analysis).
Time frame: One muscle biopsy per subject (last approximately 15 min.)
10 meter walk test
Measurement of the time it takes to walk 10 meters.
Time frame: Exam last approximately 5 min
Neurological examination and test of muscle strength
Muscle strength (in arms and legs) will be examined by the principal investigator based on the Medical Research Council (MRC) scale with values spanning from 5(=normal strength) to 1(=No contraction).
Time frame: Exam last approximately 15 min.
Questionnaires
Data will be collected using Minimal mental examination (MMSE)
Time frame: Data will be collected once for patients with LGMD2N (exam last approximately 45 min.)
Heart examination
Echocardiography and Electrocardiogram (ECG).
Time frame: Exam last approximately 45 min
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Forced Vital Capacity (FVC)
FVC is measured as the best of three attempts using a hand-held spirometer.
Time frame: Exam last approximately 15 min
Electromyography (EMG)
EMG is used for measuring nerve conducting velocity and neuromuscular activity with repetitive stimulation (3Hz).
Time frame: Exam last approximately 30 min