Clinical and myopathological characteristics of desminopathy caused by a mutation in desmin tail domain.

Background: Most of the previously described pathogenic mutations in desmin are located in highly conserved α-helical domains that play an important role in intermediate filament assembly. The role of the C-terminus non-α-helical 'tail' domain is much less investigated and until recently mutations in this domain have been implicated in only a few patients. The majority of reported desminopathy cases caused by the tail mutations were sporadic, creating a representation bias regarding the disease frequency and phenotypic characteristics.

Methods: We performed detailed genotype-phenotype analysis of autosomal dominant desminopathy associated with tail domain mutations in a four-generation autosomal dominant family with 16 members affected by a progressive cardiac and/or skeletal myopathy caused by a c.1346A>C (p.Lys449Thr) mutation located in the tail domain of desmin.

Results: Phenotypic features in patients with tail domain mutations are similar to those in patients with mutations localized in the 1B and 2B α-helical domains.

Conclusion: We recommend that the tail domain is searched for mutations as intensely as desmin coil domains which until recently were considered to be more 'functional'.