Work

A Titin Truncating Variant Causing a Dominant Myopathy With Cardiac Involvement in a Large Family

Year: 2024

Type: article

Abstract: Background: Titin truncating variants (TTNtvs) have been repeatedly reported as causative of recessive but not dominant skeletal muscle disorders. Objective: can be responsible for the observed dominant myopathy in a large family. Methods: In this case series, all available family members (8 affected and 6 healthy) belonging to a single family showing autosomal dominant inheritance were thoroughly examined clinically and genetically. Results: variant c.70051C>T p.(Arg23351*), in exon 327. RNA sequencing confirmed the lack of complete nonsense-mediated decay, and protein studies convincingly revealed expression of a shortened titin fragment of the expected size. Discussion: We conclude that a single heterozygous nonsense variant in titin occasionally can cause a dominant myopathy as shown in this large family. Therefore, monoallelic titin truncating variants should be considered as possible disease-causing variants in unsolved patients with a dominant myopathy. However, large segregation studies, muscle imaging, and RNA and protein assays are needed to support the clinical and genetic interpretation.

Source: Neurology Genetics

DOI: 10.1212/nxg.0000000000200185