Which clinical history findings are characteristic of autosomal-recessive limb-girdle muscular dystrophy 2C-2F (LGMD2C-2F)?

Updated: Aug 15, 2019
  • Author: Monica Saini, MD, MBBS, MRCP(UK); Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Answer

Sarcoglycanopathies (LGMD2C–2F; LGMDR3–R6)

In general, sarcoglycanopathies tend to cause a severe Duchenne-like phenotype, but mild Becker-like phenotypes have been described. Overall, these diseases account for about 20–25% of all LGMDs, but they are overrepresented among severe cases. LGMD2D (α-sarcoglycan [adhalin]) accounts for 40% of the sarcoglycanopathies, LGMD2C and 2E (γ-sarcoglycan and β-sarcoglycan) each account for about 23% and LGMD2F (δ-sarcoglycan) accounts for 14% of cases in the Brazilian population.

Onset is usually at ages 6–8 years, but onset at or before 2 years and as late as the teens (or even adulthood) has been reported.

Some delay in motor milestones is not uncommon.

Weakness affects the hip and abdominal and shoulder musculature. Scapular winging is more common in LGMD2C-2F than in Duchenne muscular dystrophy.

Hypertrophy of the calf is common, and the tongue muscles may become enlarged.

Progression tends to be more rapid than that of other LGMDs, with loss of ambulation usually at 12–16 years but can be as early as 10 years. Patients with a late onset tend to have a more slowly progressive course.

Recently, patients with mild forms of alpha-sarcoglycanopathy have been identified using next-generation sequencing (NGS) targeted gene panels, indicating that milder forms may be underdiagnosed. [16]

Intelligence is normal.

Cardiomyopathy is reported in about 30% of cases and is most common with LGMD2E or 2F.

Progressive weakness leads to restrictive lung disease and hypoventilation and the need for ventilatory assistance.

Death can occur as early as in the second decade of life, although some patients live into adulthood without respiratory assistance.


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