Table 2b.

Genes of Interest in the Differential Diagnosis of Late-Onset LAMA2-MD

GenesDifferential DisorderMOIClinical Features of the Differential Disorder
Overlapping w/LAMA2-MDDistinguishing from LAMA2-MD
EMD
FHL1
LMNA 		Emery-Dreifuss muscular dystrophy 1XL
AR
AD		Elbow contractures, high serum CK concentrations, prominent spinal rigidity
  • Cardiac disease (in all affected persons) w/conduction defects & arrhythmias
  • Absence of the characteristic brain MRI findings assoc w/LAMA2-MD
COL6A1
COL6A2
COL6A3 		Collagen type VI disorders (Bethlem myopathy) 2AR
AD		Elbow or Achilles tendon contractures; mildly ↑ serum CK concentrations
  • Contractures, present early in disease, can be more disabling than muscle weakness & usually → persistent severe flexion contractures.
  • If no typical skin changes (e.g., keloids), differential diagnosis is difficult.
  • Suggestive findings on muscle MRI

AD = autosomal dominant; AR = autosomal recessive; MOI = mode of inheritance; XL = X-linked

1.

Immunofluorescence and/or western blot in fresh muscle biopsies (or from other affected tissues) can be used to detect changes in emerin or FHL1 proteins.

2.

Immunohistochemical (IHC) analysis of muscle or skin biopsies can be diagnostically useful, showing variable reduction of antibody labeling against collagen VI.

From: LAMA2 Muscular Dystrophy

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