Genotype-phenotype correlations in recessive titinopathies.
Savarese MFolkhälsan Research Center, Helsinki, Finland. marco.savarese@helsinki.fi.
Vihola AFolkhälsan Research Center, Helsinki, Finland.
Oates ECSchool of Biotechnology & Biomolecular Sciences, University of New South Wales, Sydney, Australia.
Barresi RRare Diseases Advisory Group Service for Neuromuscular Diseases, Muscle Immunoanalysis Unit, Dental Hospital, and The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Translational and Clinical Research Institute, University of Newcastle, Newcastle upon Tyne, UK.
Fiorillo CPaediatric Neurology and Neuromuscular Disorders Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
Tasca GUnità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
Jokela MNeuromuscular Research Center, Tampere University Hospital and Tampere University, Tampere, Finland.
Sarkozy ADubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK.
Luo SDepartment of Neurology, Huashan Hospital Fudan University, Shanghai, China.
Díaz-Manera JNeuromuscular Disorders Unit, Neurology Department, Hospital de la Santa Creu I Sant Pau, Universidad Autónoma de Barcelona, Barcelona, Spain.
Ehrstedt CDepartment of Women and Childrens Health, Section for Paediatrics, Uppsala University, Uppsala, Sweden.
Rojas-García RNeuromuscular Disorders Unit, Neurology Department, Hospital de la Santa Creu I Sant Pau, Universidad Autónoma de Barcelona, Barcelona, Spain.
Sáenz AGroup of Neuromuscular Diseases, Neurosciences Area, Biodonostia Health Research Institute, San Sebastián, Spain.
Muelas NCentro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain.
Lonardo FUOSD Genetica Medica, AO Rummo, Benevento, Italy.
Fodstad HDepartment of Laboratory Medicine and Pathology, Division of Genetic Medicine, Lausanne University Hospital (CHUV), Lausanne, Switzerland.
Qureshi TFolkhälsan Research Center, Helsinki, Finland.
Johari MFolkhälsan Research Center, Helsinki, Finland.
Välipakka SFolkhälsan Research Center, Helsinki, Finland.
Luque HFolkhälsan Research Center, Helsinki, Finland.
Petiot PHospices Civils de Lyon, Explorations Fonctionnelles Neurologiques, Hôpital de la Croix Rousse, Lyon, France.
de Munain ALGroup of Neuromuscular Diseases, Neurosciences Area, Biodonostia Health Research Institute, San Sebastián, Spain.
Pane MPediatric Neurology and Nemo Clinical Centre, Fondazione Policlinico Universitario A. Gemelli IRCSS, Università Cattolica del Sacro Cuore, Roma, Italy.
Mercuri EPediatric Neurology and Nemo Clinical Centre, Fondazione Policlinico Universitario A. Gemelli IRCSS, Università Cattolica del Sacro Cuore, Roma, Italy.
Torella AMedical Genetics, Department of Biochemistry, Biophysics and General Pathology University of Campania 'Luigi Vanvitelli' Naples Italy, Caserta, Italy.
Nigro VMedical Genetics, Department of Biochemistry, Biophysics and General Pathology University of Campania 'Luigi Vanvitelli' Naples Italy, Caserta, Italy.
English
PURPOSE High throughput sequencing analysis has facilitated the rapid analysis of the entire titin (TTN) coding sequence. This has resulted in the identification of a growing number of recessive titinopathy patients. The aim of this study was to (1) characterize the causative genetic variants and clinical features of the largest cohort of recessive titinopathy patients reported to date and (2) to evaluate genotype-phenotype correlations in this cohort.
METHODS We analyzed clinical and genetic data in a cohort of patients with biallelic pathogenic or likely pathogenic TTN variants. The cohort included both previously reported cases (100 patients from 81 unrelated families) and unreported cases (23 patients from 20 unrelated families).
RESULTS Overall, 132 causative variants were identified in cohort members. More than half of the cases had hypotonia at birth or muscle weakness and a delayed motor development within the first 12 months of life (congenital myopathy) with causative variants located along the entire gene. The remaining patients had a distal or proximal phenotype and a childhood or later (noncongenital) onset. All noncongenital cases had at least one pathogenic variant in one of the final three TTN exons (362-364).
CONCLUSION Our findings suggest a novel association between the location of nonsense variants and the clinical severity of the disease.