User:Mr. Ibrahem/Andersen–Tawil syndrome

Andersen–Tawil syndrome, also called long QT syndrome 7, is a genetic disorder. Features include a long QT interval with a tendency for abnormal heart rhythms; episodes of muscle weakness known as periodic paralysis; abnormal facial features; and a short height. Some degree of chronic weakness may also be present. Symptoms generally begin in childhood; though some never develop symptoms. Complications may include sudden cardiac death and scoliosis.

In about 60% of cases it occurs due to a mutation in the KCNJ2 gene which encodes an ion channel that transports potassium. Mutations in KCNJ5 may also result in the condition and in other cases the cause remains unknown. Generally it is inherited from a person's parents in an autosomal dominant pattern. Some cases occur due to a new mutation in early development. Diagnosis is based on symptoms and may be supported by genetic testing.

Management involves evaluation for certain conditions, treatment of specific symptoms when they occur, and efforts to prevent symptoms. Periodic paralysis associated with a potassium of less than 3.0 mmol/L may be treated with 20 mEq potassium by mouth, which may be repeated. Efforts to prevent attacks may include a carbonic anhydrase inhibitors such as acetazolamide or potassium supplements. The abnormal heart rhythms may be treated with flecainide, though an implantable defibrillator may be required. Medications that prolong the QT should be avoided. Relatives should be checked for the condition.

Andersen–Tawil syndrome is rare with about one person in every million affected. Males and females are affected with similar frequency. Early descriptions of the condition are believed to date from 1963 by Klein, followed by more detailed descriptions in 1971 by Ellen Andersen, and in 1994 by Rabi Tawil.