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Late onset muscular dystrophy with cerebral white matter changes due to partial merosin deficiency
1Department of Adult Neurology, Hacettepe University Hospitals, Ankara, Turkey.
Abstract:
Merosin-deficient congenital muscular dystrophy (CMD) is an autosomal recessive condition usually with onset at birth or within the first months of life. Affected children are severely disabled and usually do not achieve the ability to walk without support. They invariably have white matter abnormalities on brain magnetic resonance imaging (MRI). We report a 29-year-old man with a late childhood onset limb-girdle type muscular dystrophy and cerebral white matter changes on MRI. Immunocyto-chemical studies of the patient's muscle biopsy showed a reduction in expression of the laminin alpha 2 chain of merosin. The patient had three affected siblings, and microsatellite genotyping confirmed linkage to the laminin alpha 2 locus (LAMA2) on chromosome 6q2 in this family. This case probably represents a milder allelic variant of classical merosin-deficient CMD. Merosin status should be assessed in patients with late-onset limb girdle muscular dystrophy.
Insights
This study identifies a milder variant of merosin-deficient congenital muscular dystrophy (CMD) presenting in late childhood. Assessing merosin status is crucial for diagnosing limb-girdle muscular dystrophy with white matter changes.
Area of Science:
- Neurology
- Genetics
- Muscular Dystrophy Research
Background:
- Merosin-deficient congenital muscular dystrophy (CMD) typically presents at birth with severe disability and white matter abnormalities.
- Classical CMD is linked to mutations in the LAMA2 gene, affecting laminin alpha 2 chain expression.
Purpose of the Study:
- To investigate a case of late-onset limb-girdle muscular dystrophy with cerebral white matter changes.
- To determine the genetic basis and merosin status in a family with muscular dystrophy.
Main Methods:
- Clinical assessment of a 29-year-old male with late-onset muscular dystrophy.
- Immunocytochemical analysis of muscle biopsy to assess merosin (laminin alpha 2 chain) expression.
- Microsatellite genotyping to confirm genetic linkage to the LAMA2 locus.
Main Results:
- The patient exhibited limb-girdle muscular dystrophy with cerebral white matter changes on MRI.
- Muscle biopsy revealed reduced expression of the laminin alpha 2 chain of merosin.
- Genetic analysis confirmed linkage to the LAMA2 gene on chromosome 6q2 in the affected family.
Conclusions:
- This case represents a milder allelic variant of merosin-deficient CMD with late-onset presentation.
- Merosin status assessment is recommended for patients diagnosed with late-onset limb-girdle muscular dystrophy and white matter changes.