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[A pedigree of autosomal dominant limb-girdle myopathy with rimmed vacuole formation]
Abstract:
We describe a kindred with autosomal dominant myopathy with preferential proximal limb muscle involvement. This disorder is characterized clinically by early adult onset, slow progression, normal life expectancy, weakness and atrophy of proximal limb muscles, especially in the lower limbs. Laboratory examinations showed myopathic changes mixed with neuropathic components on needle electromyography, slight elevation of serum creatine kinase, and absent cardiac involvement. In biopsied muscle findings of two patients, the presence of rimmed vacuoles was the most striking finding to explain muscle degeneration, though a few necrotic fibers were present. The pathologic and clinical findings in the present family are almost similar to those seen in "adult-onset autosomal dominant limb-girdle muscular dystrophy" reported by Chutkow et al.
Insights
This study identifies an autosomal dominant myopathy causing progressive proximal limb muscle weakness. Key findings include rimmed vacuoles in muscle biopsies, suggesting a specific degenerative process in this limb-girdle muscular dystrophy variant.
Area of Science:
- Neurology
- Genetics
- Pathology
Background:
- Autosomal dominant myopathies represent a heterogeneous group of inherited muscle disorders.
- Limb-girdle muscular dystrophies (LGMDs) are characterized by progressive weakness and atrophy primarily affecting the shoulder and hip girdle muscles.
- Understanding the genetic and pathological basis of LGMD subtypes is crucial for diagnosis and potential therapeutic strategies.
Observation:
- A kindred presented with autosomal dominant myopathy featuring proximal limb muscle weakness, particularly in the lower limbs.
- Clinical onset was in early adulthood, with slow progression and normal life expectancy.
- Electromyography revealed mixed myopathic and neuropathic changes, with slightly elevated serum creatine kinase levels and no cardiac involvement.
Findings:
- Muscle biopsies from affected individuals showed prominent rimmed vacuoles, indicative of muscle degeneration.
- A few necrotic muscle fibers were also observed.
- The clinical and pathological features closely resemble previously reported cases of adult-onset autosomal dominant limb-girdle muscular dystrophy.
Implications:
- This description expands the known spectrum of autosomal dominant limb-girdle muscular dystrophies.
- The presence of rimmed vacuoles may serve as a diagnostic hallmark for this specific myopathy.
- Further research into the genetic underpinnings and molecular mechanisms of this disorder is warranted for improved patient management.