A novel deep intronic variant in LAMA2 identified by RNA sequencing.

ABSTRACT

LAMA2-related muscular dystrophy is caused by pathogenic variants of the alpha2 subunit of Laminin. This common form of muscular dystrophy is characterized by elevated CK >1000IU/L, dystrophic changes on muscle biopsy, complete or partial absence of merosin staining, and both central and peripheral nervous system involvement. Advancements in genomic testing using NGS and wider application of RNA sequencing has expanded our knowledge of novel non-coding pathogenic variants in LAMA2. RNA sequencing is an increasingly utilized technique to directly analyze the transcriptome, through creation of a complementary DNA (cDNA) from the transcript within a tissue sample. Here we describe a homozygous deep intronic variant that produces a novel splice junction in LAMA2 identified by RNA sequencing analysis in a patient with a clinical phenotype in keeping with LAMA2-related muscular dystrophy. Furthermore, in this case merosin staining was retained suggestive of a functional deficit.