Andersen-Tawil syndrome overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Charmaine Patel, M.D. [2]; Raviteja Guddeti, M.B.B.S. [3]
Overview
Andersen-Tawil syndrome is a form of long QT syndrome. It is a rare genetic disorder, and is inherited in an autosomal dominant pattern and has characteristic features of episodes of paralysis, ventricular arrhythmia, and dysmorphic features such as hypertelorism, micrognathia, and low set ears. Patients with Andersen-Tawil syndrome usually present in childhood with spontaneous attacks of paralysis which may be associated with normal, high, or low potassium levels. Overview Historical Perspective Classification Pathophysiology Causes Differentiating Xyz from Other Diseases Epidemiology and Demographics Risk Factors Screening Natural History, Complications, and Prognosis Diagnosis Diagnostic Study of Choice History and Symptoms Physical Examination Laboratory Findings Electrocardiogram X-ray Echocardiography and Ultrasound CT scan MRI Other Imaging Findings Other Diagnostic Studies Treatment Medical Therapy Interventions Surgery Primary Prevention Secondary Prevention
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).