Andersen-Tawil syndrome overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vamsikrishna Gunnam M.B.B.S [2]
Overview
Historical Perspective
Andersen-Tawil syndrome (ATS) is a very rare syndrome which is characterized by periodic paralysis, arrhythmias and long QT interval. Ellen Andersen was the first to describe the Andersen-Tawil syndrome (ATS) in 1971.
Classification
Andersen–Tawil syndrome may be classified according to genetic mutations into two groups: Type 1 Andersen–Tawil syndrome and type 2 Andersen–Tawil syndrome.
Pathophysiology
It is understood that Andersen-Tawil syndrome is the result of mutation in KCNJ2 gene which encodes for Kir2.1 inward rectifier potassium channel that involves in cardiac repolarization phase. The movement of potassium ions through these channels is critical for maintaining the normal functions of skeletal muscles which are used for movement and cardiac muscle. Andersen-Tawil syndrome is a rare syndrome transmitted in autosomal dominant pattern.
Causes
Genes involved in the pathogenesis of Andersen-Tawil syndrome include KCNJ2 gene, KCNJ5 gene and an unknown gene.
Differentiating Xyz from Other Diseases
Andersen-Tawil syndrome must be differentiated from Romano-Ward syndrome, Timothy syndrome, Jervell and Lange-Nielsen syndrome (JLNS), Brugada syndrome, Sudden infant death syndrome (SIDS), Hypokalemic periodic paralysis, Hyperkalemic periodic paralysis and Thyrotoxic periodic paralysis.
Epidemiology and Demographics
Andersen-Tawil syndrome is a rare hereditary multisystem disorder transmitted in autosomal dominant pattern. Only 200 cases of Andersen-Tawil syndrome were reported worldwide.
Risk Factors
Risk factors in Andersen-Tawil syndrome include a family member who is having KCNJ2 gene mutation.
Screening
There is insufficient evidence to recommend routine screening for Andersen-Tawil syndrome. But when a patient with positive KCNJ2 mutation follow the patient with ECG and holter monitoring.
Natural History, Complications, and Prognosis
If left untreated, patients with Andersen-Tawil syndrome may progress to develop periodic paralysis, cardiac arrhythmias and can lead to the death of the patient. Common complications of Andersen-Tawil syndrome include neuromuscular symptoms and malignant hyperthermia. Prognosis is generally range from good to poor.
Diagnosis
Diagnostic Study of Choice
The diagnosis of Andersen-Tawil syndrome (ATS) is suspected in individuals whose satisfies either criteria A and criteria B with molecular genetic testing to confirm.
History and Symptoms
Patients with Andersen-Tawil Syndrome may have a positive history of periodic paralysis, cardiac symptoms, ventricular arrhythmias and common symptoms syncope, muscular weakness and Skeletal developmental abnormalities
Physical Examination
Patients with Andersen-Tawil syndrome usually appear shorter than normal. Physical examination of patients with Andersen-Tawil syndrome is usually remarkable for hypoplastic mandible, micrognathia, broad nose, low set ears and clinodactyly.
Laboratory Findings
Laboratory findings consistent with the diagnosis of Andersen-Tawil syndrome (ATS) include serum potassium levels. Some patients with Andersen-Tawil syndrome(ATS) may have elevated/reduced concentration of serum potassium levels, which is usually suggestive of Andersen-Tawil syndrome (ATS).
Electrocardiogram
An ECG may be very helpful in the diagnosis of Andersen-Tawil Syndrome. Findings on an ECG diagnostic of Andersen-Tawil Syndrome include a long QTc (LQT) interval, U waves, wide T-U junction and T-waves.
X-ray
There are no x-ray findings associated with Andersen-Tawil syndrome.
Echocardiography and Ultrasound
There are no ultrasound findings associated with Andersen-Tawil syndrome.
CT scan
There are no CT scan findings associated with Andersen-Tawil syndrome.
MRI
There are no MRI scan findings associated with Andersen-Tawil syndrome.
Other Imaging Findings
There are no other imaging findings associated with Andersen-Tawil syndrome.
Other Diagnostic Studies
There are no other diagnostic findings associated with Andersen-Tawil syndrome.
Treatment
Medical Therapy
There is no treatment for Andersen-Tawil Syndrome; the mainstay of therapy is to treat the symptoms and manage the patient. Potassium levels plays an important role in the management of the symptoms.
Surgery
Surgical intervention is not recommended for the management of Andersen-Tawil syndrome (ATS).
Primary Prevention
Effective measures for the primary prevention of Andersen-Tawil syndrome (ATS) include Lifestyle modifications, carbonic anhydrase inhibitors using, potassium supplements and cardioverter-defibrillator.
Secondary Prevention
Effective measures for the secondary prevention of Andersen-Tawil syndrome (ATS) include avoidance of some antiarrhythmic drugs and anesthetic precautions.