The limb-girdle muscular dystrophies and the dystrophinopathies

SJP Iyadurai, JT Kissel - CONTINUUM: Lifelong Learning in …, 2016 - journals.lww.com
SJP Iyadurai, JT Kissel
CONTINUUM: Lifelong Learning in Neurology, 2016journals.lww.com
Abstract Purpose of Review: The classic approach to identifying and accurately diagnosing
limb-girdle muscular dystrophies (LGMDs) relied heavily on phenotypic characterization and
ancillary studies including muscle biopsy. Because of rapid advances in genetic sequencing
methodologies, several additional LGMDs have been molecularly characterized, and the
diagnostic approach to these disorders has been simplified. This article summarizes the
epidemiology, clinical features, and genetic defects underlying the LGMDs. Recent Findings …
Abstract
Purpose of Review: The classic approach to identifying and accurately diagnosing limb-girdle muscular dystrophies (LGMDs) relied heavily on phenotypic characterization and ancillary studies including muscle biopsy. Because of rapid advances in genetic sequencing methodologies, several additional LGMDs have been molecularly characterized, and the diagnostic approach to these disorders has been simplified. This article summarizes the epidemiology, clinical features, and genetic defects underlying the LGMDs.
Recent Findings: In recent years, the advent of next-generation sequencing has heralded an era of molecular diagnosis in conjunction with physical characterization. Inadvertently, this process has also led to the “next-generation aftermath,” whereby variants of unknown significance are identified in most patients. Similar to the published diagnostic and treatment guidelines for Duchenne muscular dystrophy, diagnostic and treatment guidelines have recently been published for LGMDs. In addition, the first medication (based on the exon-skipping strategy) for treatment of patients with a subset of Duchenne muscular dystrophy has been recently approved by the US Food and Drug Administration (FDA).
Summary: The LGMDs are a heterogeneous group of hereditary, progressive, and degenerative neuromuscular disorders that present with primary symptoms of shoulder girdle and pelvic girdle weakness. Although a combination of clinical and molecular genetic evaluations may be sufficient for accurate diagnosis of LGMDs in many cases, the contribution of imaging and histopathologic correlations still remains a critical, if not a necessary, component of evaluation in some cases.
Lippincott Williams & Wilkins