A KCNE1 missense variant (V47I) causing exercise-induced long QT syndrome (Romano Ward)

We present a case of a 28-year-old female who was referred for a second opinion regarding management of mitral valve prolapse (MVP). At age 14 years she was diagnosed with a murmur. At age 23 years she developed daily episodes of palpitations with exertion, occasionally with dizziness but never with syncope. She noted intermittent tinnitus but had no vertigo or loss of auditory acuity. Her family history was significant for the witnessed sudden death of her mother at age 40 years. The cause of death per the autopsy report was “mitral valve prolapse”. Her younger sister, age 24 years also has MVP. On examination, a late systolic murmur was appreciated at the apex, consistent with MVP and moderate mitral regurgitation (MR).