Test Background

* Next generation sequencing to identify point mutations, small deletions and insertions, and splice site mutations
* 10 genes that are most frequently causative of childhood-onset muscular dystrophy including CAPN3, CAV3, DMD, FKRP, LMNA, SGCA, SGCB, SGCD, SGCG, TRIM32
The muscular dystrophies are a genetically heterogeneous group of conditions that are clinically classified based on age of onset, distribution of muscle weakness, progression of weakness, and non-neuromuscular features. However, due to the overlapping features, it is often difficult to distinguish one condition from another. The Muscular Dystrophy Panel uses massive parallel sequencing technology to identify point mutations, small deletions and insertions, and splice site mutations within ten of the causative genes encountered most frequently in childhood-onset muscular dystrophy. A subset of individuals with apparently isolated dilated cardiomyopathy is also expected to have mutations identified in these genes.

Dystrophinopathies are the most common forms of muscular dystrophy and follow an X-linked pattern of inheritance. Point mutations in DMD are identified in approximately one-third of affected individuals. Large deletions or duplications in DMD, seen in the remaining two-thirds of affected individuals, will not be detected by this assay. Deletion/duplication testing is available for this purpose and should be performed prior to ordering the ClariView? Panel: Muscular Dystrophy if DMD/BMD is suspected.

Limb-girdle muscular dystrophies present with weakness after birth and are generally indistinguishable from one another clinically. They may follow an autosomal recessive or autosomal dominant pattern of inheritance and the causative genes included in this panel are CAPN3, CAV3, TRIM32, SGCA, SGCB, SGCD, and SGCG.

Congenital muscular dystrophies typically present with weakness at birth and may include intellectual disability. They may follow an autosomal recessive or autosomal dominant pattern of inheritance and the causative genes included in this panel are FKRP and LMNA. Mutations in these genes are associated with multiple neuromuscular phenotypes in addition to congenital muscular dystrophy, including limb-girdle and Emery-Dreifuss muscular dystrophies.

Gene(s)

CAPN3, CAV3, DMD, FKRP, LMNA, SGCA, SGCB, SGCD, SGCG, TRIM32