<unk>  classically comprises three groups of features: abnormal electrical function of the heart, hypokalemic periodic paralysis, and characteristic physical features, although some of those affected will not exhibit all aspects of the condition. Electrocardiogram showing bidirectional Ventricular Tachycardia in a 9-year-old female with<unk> <unk>  affects the heart by prolonging the QT interval, a measure of how long it takes the heart to relax after each heart beat. This, as in other forms of long QT syndrome, can lead to abnormal heart rhythms such as ventricular ectopy or ventricular tachycardia causing palpitations. The ventricular tachycardia seen in<unk>  often takes a form known as bidirectional ventricular tachycardia. The arrhythmias seen in association with the condition can cause sudden cardiac death, but the risk of this is lower than in other forms of long QT syndrome. Clinodactyly – abnormal curvature of 5th finger towards 4th finger The physical abnormalities associated with<unk>  typically affect the head, face, limbs and spine. Abnormalities of the head and face include an unusually small lower jaw (micrognathia), low-set ears, widely spaced eyes (hypertelorism), a broad forehead and nasal root, a high arched or cleft palate, and a long narrow head (scaphocephaly). Abnormalities of the limbs and spine include an abnormal curvature of the fingers, particularly the fifth finger (clinodactyly), fused fingers or toes (syndactyly), short stature, and a curved spine (scoliosis). The third key feature of<unk>  is intermittent muscle weakness. This can last from seconds to minutes, but in some cases may last for days at a time. Weakness often occurs at times when the levels of potassium in the blood are lower than normal (hypokalaemia), and is referred to as hypokalaemic periodic paralysis. This weakness can however occur at times when potassium levels are normal, triggered by other factors including exercise, cold, or even menstruation.
Andersen–Tawil syndrome
Jervell and Lange-Nielsen syndrome
Dennie–Marfan syndrome
Romano–Ward syndrome
Timothy syndrome
Marfan syndrome
Catecholaminergic polymorphic ventricular tachycardia
CAMFAK syndrome