Affiliations: [a] Queen Square Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, and Department of Neuromuscular Diseases, UCL Institute of Neurology, London, UK
| [b] Royal Berkshire Hospital Reading and Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| [c] Neurogenetics Unit, Institute of Neurology, Queen Square, London, UK
| [d] Inherited Cardiovascular Diseases Unit, Barts Heart Centre, Barts Healthcare NHS Trust, London, UK
| [e] Atkinson Morley Neuromuscular Centre, Department of Neurology, St George’s University Hospitals NHS Foundation Trust, London, UK
Correspondence to: Emma Matthews Atkinson Morley Neuromuscular Centre, Department of Neurology, St George’s University Hospitals NHS Foundation Trust, SW17 0QT, London, UK. Tel.: +44 0203 108 7513; Fax: +44 020 3448 3633; E-mail: [email protected].
Abstract: Andersen-Tawil syndrome (ATS) is a rare autosomal dominant neuromuscular disorder due to mutations in the KCNJ2 gene. The classical phenotype of ATS consists of a triad of periodic paralysis, cardiac conduction abnormalities and dysmorphic features. Episodes of either muscle weakness or cardiac arrhythmia may predominate however, and dysmorphic features may be subtle, masking the true breadth of the clinical presentation, and posing a diagnostic challenge. The severity of cardiac involvement varies but includes reports of life-threatening events or sudden cardiac death, usually attributed to ventricular tachyarrhythmias. We report the first case of advanced atrioventricular (AV) block in ATS and highlight clinical factors that may delay diagnosis.