question: What is the Timothy syndrome?
answer: Timothy syndrome is a multisystem disorder characterized by cardiac, hand/foot, facial, and neurodevelopmental features. The two forms are type 1 (classic) and type 2, a rare form caused by mutations in a transcript variant of the same gene. Cardiac findings include a rate-corrected QT interval of between 480 ms and 700 ms and congenital heart defects (patent ductus arteriosus, patent foramen ovale, ventricular septal defect, tetralogy of Fallot, hypertrophic cardiomyopathy). Hand/foot findings are unilateral or bilateral cutaneous syndactyly variably involving fingers two (index), three (middle), four (ring), and five (little) and bilateral cutaneous syndactyly of toes two and three. Facial findings include flat nasal bridge, low-set ears, thin upper lip, and round face. Neuropsychiatric involvement includes global developmental delays and autism spectrum disorders. Ventricular tachyarrhythmia is the leading cause of death, followed by infection and complications of intractable hypoglycemia. Average age of death is 2.5 years.