Novel compound heterozygous PLEC mutations lead to early-onset limb-girdle muscular dystrophy 2Q

Limb-girdle muscular dystrophy 2Q (LGMD2Q) is a specific mutation in the plectin (PLEC1) gene at chromosome 8q24.3. In the present study, targeted sequencing using a muscle disease gene panel was performed in a patient with muscular dystrophy. The family members were confirmed by Sanger sequencing. The PolyPhen-2, SIFT and MutationTaster tools were used to predicted the possible effect of the mutations. Immunocytochemistry was used to visualize and localize the plectin protein within the gastrocnemius. Novel compound heterozygous mutations c.5995C>T (p.Arg1999Trp) and c.9940T>A (p.Phe3314 Ile) in the PLEC gene were identified to be the genetic cause of LGMD2Q in this family. These variants were absent in 200 normal controls. Furthermore, defects in the plectin protein within the gastrocnemius were determined using immunocytochemistry. To the best of our knowledge, the present study provides the second report on plectin-associated LGMD2Q without other symptoms, although the genotype identified was novel. The missense mutations in the proband were considered to be an explanation for the symptom. These findings extend current knowledge of the mutation spectrum of the PLEC gene associated with LGMD2Q.