Limb Girdle Muscular Dystrophy LGMD
Limb Girdle Muscular Dystrophy (LGMD) is a group of genetic muscle disorders that primarily affect the muscles around the shoulders (pectoral girdle) and hips (pelvic girdle). It leads to progressive muscle weakness and wasting over time.
Types of LGMD
LGMD is classified into two major categories based on inheritance patterns:
1. LGMD Type 1 (Autosomal Dominant) – Less common, passed from one affected parent.
2. LGMD Type 2 (Autosomal Recessive) – More common, inherited when both parents are carriers.
Each type is further divided based on specific genetic mutations. Some common subtypes include:
LGMD2A (Calpainopathy) – The most common type, caused by mutations in the CAPN3 gene.
LGMD2B (Dysferlinopathy) – Linked to mutations in the DYSF gene.
LGMD2C, 2D, 2E, 2F (Sarcoglycanopathies) – Result from defects in sarcoglycan proteins.
LGMD2I (FKRP-related LGMD) – One of the milder forms but can still cause heart and breathing issues.
Causes of LGMD
LGMD is caused by genetic mutations that lead to defective proteins necessary for muscle function. These mutations affect:
Muscle structure and repair (e.g., CAPN3, DYSF, FKRP genes).
Proteins that connect muscle fibers to surrounding tissue (e.g., sarcoglycanopathies).
Metabolic or mitochondrial functions in some rare cases.
Signs and Symptoms
Symptoms vary depending on the type and severity but generally include:
Progressive weakness in the shoulders, upper arms, hips, and thighs.
Difficulty climbing stairs, standing from a sitting position, or walking.
Frequent falls and trouble maintaining balance.
Muscle wasting (atrophy) over time.
Weakness in respiratory muscles, leading to breathing difficulties in advanced stages.
Some types may also cause heart complications (cardiomyopathy) and contractures (joint stiffness).
Diagnosis of LGMD
A combination of tests is used to diagnose LGMD, including:
1. Clinical Examination – Assessing muscle weakness and movement difficulties.
2. Creatine Kinase (CK) Test – Measures CK enzyme levels, which are elevated in muscle damage.
3. Electromyography (EMG) – Evaluates muscle electrical activity.
4. Muscle Biopsy – Identifies structural muscle abnormalities.
5. Genetic Testing – Confirms the specific mutation responsible for LGMD.
6. Cardiac and Respiratory Tests – To check for heart and lung involvement.
Treatment for LGMD
There is no cure for LGMD, but treatments focus on managing symptoms and improving quality of life:
Physical Therapy – Helps maintain mobility and prevent contractures.
Assistive Devices – Braces, walkers, and wheelchairs support movement.
Respiratory Support – In severe cases, ventilators or BiPAP machines may be needed.
Medications – Some experimental treatments, corticosteroids (in select cases), and gene therapy trials are being explored.
Cardiac Monitoring – Regular check-ups for those at risk of heart complications.
