Abstract

Titinopathies are a relatively recently discovered and constantly expanding group of muscular dystrophies caused by changes in the TTN gene, which encodes the giant muscle protein titin. Depending on the subform, titinopathies can include weakness in different muscle groups, loss of muscle mass, and in some cases, cardiomyopathy and breathing disorders. The routine use of large gene panel sequencing analysis in the diagnosis of hereditary diseases has made it possible to discover disease-causing changes in the TTN gene. In Estonia, systematic research into muscular dystrophies caused by TTN gene mutations began in 2020 and to date, approximately 20 patients with early or late onset titinopathy are known in Estonia.
This article aims to provide an overview of currently known titinopathies, including their etiology, pathogenesis, clinical presentation, and diagnosis. The article focuses mainly on skeletal muscle dystrophies. For illustration, it includes a case report of a patient with late-onset titinopathy, detailing the progression of the disease, clinical presentation, and the journey to obtain accurate diagnosis.