What Is Limb-Girdle Muscular Dystrophy (LGMD)?

Limb-girdle muscular dystrophy, or LGMD, refers to a group of different disorders that are characterized by muscle wasting at the shoulders and the hips. The disease’s name, first coined in 1954, refers to the characteristic weakness at the “shoulder girdle” and “hip girdle” — the bony structures surrounding the shoulders and hips, respectively.

LGMD is estimated to affect between one in 14,500 to one in 123,000 people worldwide.

Types and causes of LGMD

LGMD is caused by genetic mutations, which may be passed from parents to their biological children. The condition is broadly grouped into two types, based on the mode of inheritance. In type 1, LGMD is inherited in an autosomal dominant manner, meaning that one disease-causing mutation inherited from a parent is enough to cause the disease. In type 2, which is more common, LGMD is inherited following an autosomal recessive pattern, meaning that disease-causing mutations must be inherited from both parents for LGMD to develop.

The disorder is further grouped into subtypes based on the specific gene that is mutated. To date, more than 30 different genetic subtypes of LGMD have been described. Due to differences in classification systems, some subtypes have multiple names that may be used (for example, “2A” and “R1” refer to the same subtype). A full list of the current classification of LGMD types (and the associated mutated genes) is below.

  • 1A (MYOT gene)
  • 1B (LMNA gene)
  • 1C (CAV3 gene)
  • 1D/D1 (DNAJB6 gene)
  • 1F/D2 (TPNO3 gene)
  • D3 (4p21.22 region)
  • D4 (CAPN3 gene)
  • 2A/R1 (CAPN3 gene)
  • 2B/R2 (DYSF gene)
  • 2C/R5 (SGCG gene)
  • 2D/R3 (SGCA gene)
  • 2E/R4 (SGCB gene)
  • 2F/R6 (SGCD gene)
  • 2G/R7 (TCAP gene)
  • 2H/R8 (TRIM32 gene)
  • 2I/R9 (FKRP gene)
  • 2J/R10 (TTN gene)
  • 2K/R11 (POMT1 gene)
  • 2L/R12 (ANO5 gene)
  • 2M/R13 (FKTN gene)
  • 2N/R14 (POMT2 gene)
  • 2O/R15 (POMGnT1 gene)
  • 2P/R16 (DAG1 gene)
  • 2Q/R17 (PLEC1 gene)
  • 2R/R18 (DES gene)
  • 2S/R19 (TRAPPC11 gene)
  • 2T/R20 (GMPPB gene)

Symptoms of LGMD

All types of LGMD are characterized by weakness and wasting of the muscles around the shoulders and hips, which typically gets progressively worse over time. The age at which symptoms first occur, and the rate of disease progression, varies widely across the different subtypes, and even among individuals with the same subtype. In general, people with symptoms that become apparent earlier in life tend also to experience a faster rate of disease progression.

Often, the first noticeable symptoms of LGMD are related to weakness around the hips. Patients may walk with an unusual “waddling” gait, or walk on their toes. They also may have difficulty rising from a seated position or climbing up stairs. As LGMD progresses, some patients may require a wheelchair or other assistive devices to get around.

Weakness around the shoulders can make it difficult to reach the arms up or carry heavy objects. Shoulder weakness also can contribute to physical abnormalities like scapular winging — when the shoulder blades stick out — or abnormal curvature of the spine.

Joint stiffness and muscle cramps are common in LGMD. Some forms of the disease can cause weakness and damage in the cardiac muscle or the respiratory muscles required to pull air in and out of the lungs, making breathing difficult. Developmental delay and intellectual disability have been linked with certain types of LGMD.

Management and prognosis of LGMD

The prognosis of LGMD depends on the subtype of disease, and also other details such as age at onset and rate of progression. At present, no therapies can slow or stop the progression of LGMD, though numerous experimental treatments are in development.

Medical management of LGMD generally involves physical or occupational therapy and other interventions that can help patients to function better in day-to-day life, alongside routine monitoring to detect any developing problems so they can be managed.

 

Last updated: Jan. 24, 2022, by Marisa Wexler MS

 


Muscular Dystrophy News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.