Diagnostic approach to the congenital muscular dystrophies

Bönnemann CG, Wang CH, Quijano-Roy S, et al. Diagnostic approach to the congenital muscular dystrophies. Neuromuscul Disord. 2014;24(4):289‐311. doi:10.1016/j.nmd.2013.12.011

Abstract

Congenital muscular dystrophies (CMDs) are early onset disorders of muscle with histological features suggesting a dystrophic process. The congenital muscular dystrophies as a group encompass great clinical and genetic heterogeneity so that achieving an accurate genetic diagnosis has become increasingly challenging, even in the age of next generation sequencing. In this document we review the diagnostic features, differential diagnostic considerations and available diagnostic tools for the various CMD subtypes and provide a systematic guide to the use of these resources for achieving an accurate molecular diagnosis. An International Committee on the Standard of Care for Congenital Muscular Dystrophies composed of experts on various aspects relevant to the CMDs performed a review of the available literature as well as of the unpublished expertise represented by the members of the committee and their contacts. This process was refined by two rounds of online surveys and followed by a three-day meeting at which the conclusions were presented and further refined. The combined consensus summarized in this document allows the physician to recognize the presence of a CMD in a child with weakness based on history, clinical examination, muscle biopsy results, and imaging. It will be helpful in suspecting a specific CMD subtype in order to prioritize testing to arrive at a final genetic diagnosis.

A–D: Differential diagnostic considerations for various clinical findings in infancy (A) and beyond infancy (B and C), as well as for various laboratory findings that may be available at the outset of the diagnostic encounter (D). Note: The most important tools in the clinical differential diagnosis are: EMG/NCV to diagnose neurogenic involvement, muscle biopsy, and selective biochemical and genetic testing. The differential diagnostic considerations are not exhaustive but highlight a few of the more relevant conditions to consider with a given clinical picture. To save space we are only using the gene/protein symbols to indicate specific diagnosis.