Neuromuscular involvement in various types of Ehlers-Danlos syndrome.
OBJECTIVE
Ehlers-Danlos syndrome (EDS) is a clinically and genetically heterogeneous group of heritable connective tissue disorders characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. Muscle involvement is plausible based on recently discovered interactions between muscle cells and extracellular matrix molecules; however, muscle symptoms are only sporadically reported. We designed a cross-sectional study to find out whether neuromuscular features are part of EDS.


METHODS
Standardized questionnaires, physical examination, nerve conduction studies, electromyography, muscle ultrasound, and muscle biopsy were performed in 40 EDS patients with the vascular, classic, tenascin-X (TNX)-deficient type EDS, and hypermobility type of EDS caused by TNXB haploinsufficiency.


RESULTS
Muscle weakness, myalgia, and easy fatigability were reported by the majority of patients. Mild-to-moderate muscle weakness (85%) and reduction of vibration sense (60%) were common. Nerve conduction studies demonstrated axonal polyneuropathy in five patients (13%). Needle electromyography myopathic features in nine patients (26%) and a mixed neurogenic-myopathic pattern in most (60%). Muscle ultrasound showed increased echo-intensity (48%) and atrophy (50%). Mild myopathic features were seen on muscle biopsy of five patients (28%). Overall, patients with the hypermobility type EDS caused by TNXB haploinsufficiency were least affected.


CONCLUSIONS
Mild-to-moderate neuromuscular involvement is common in various types of EDS, with a remarkable relation between residual TNX level and degree of neuromuscular involvement, compatible with a dose-effect relation. The findings of this study should increase awareness of neuromuscular symptoms in EDS patients and improve clinical care. They also point to a role of the extracellular matrix in muscle and peripheral nerve function.
Voermans
Nicol C
NC
Department of Neurology, Neuromuscular Centre Nijmegen, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. n.voermans@neuro.umcn.nl
van Alfen
Nens
N
Pillen
Sigrid
S
Lammens
Martin
M
Schalkwijk
Joost
J
Zwarts
Machiel J
MJ
van Rooij
Iris A
IA
Hamel
Ben C J
BC
van Engelen
Baiel G
BG
D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D004535:Ehlers-Danlos Syndrome / Q000145:classification* / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D018908:Muscle Weakness / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology* / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology; D009469:Neuromuscular Junction / Q000473:pathology* / Q000502:physiology; D011795:Surveys and Questionnaires; D055815:Young Adult