0 avis
Severe axial muscular involvement in Laing distal myopathy with a thumbprint finding on MRI
Archive ouverte
International audience. Mutations in the MYH7 gene are implicated in a heterogeneous group of diseases including Laing distal myopathy. We present 8 patients (M:F ratio = 5:3) with different mutations in the MYH7 gene with early-onset distal myopathy, typical abnormal gait and severe axial muscular involvement without cardiomyopathy. All patients had normal developmental milestones then started having gait abnormalities. 7 of them were ambulant at last follow up (two at 12 years and the others at adulthood) and one wheel chair bound at 33 years. Spinal deformity was always present and was characterized by scoliosis, cervical hyperextension, and spine bending forward thus giving them the “sphinx” phenotype. Clear weakness and muscle atrophy affected predominantly distal portions of limbs and cervical flexors, wrist and finger extensors in the upper limb, and hip extensors, foot dorsiflexors in the lower limbs muscles.8 MRIs were performed, 6 of them were whole body muscular MRIs and showed atrophy and fatty infiltration in thoracic and lumbar erector spinae in all. Fatty infiltration was also seen mainly in gluteus minimus, short head of the biceps femoris, tibialis anterior, soleus, and extensor digitorum longus. The most important finding on WBMRI was the presence of an abnormal signal at the central part of the muscles with “in bands” intramuscular striation and relative sparing of the periphery (inverted collagen pattern) seen in the soleus mainly but also in more muscles as the disease progressed. Muscle biopsy findings were variable showing occasionally cores, fiber size disproportion (could be type 1 or type 2), neurogenic signs, or normal aspect. Myogenic pattern was seen on EMG in all cases, however in 2 patients previous EMG that was done in early childhood showed a neurogenic pattern. Our series extends the spectrum of MYH7-related phenotypes to add the “sphinx” phenotype. WBMRI showed a characteristic finding with inverted collagen sign that seem specific for this condition.
Consulter en ligne
Suggestions
Du même auteur
