! Note to be confused with Andersen's disease which is a type IV glycogenosis !

[MIM 170 390] 

(Andersen-Tawil syndrome, Andersen syndrome type 1 or 2, cardiodysrythmic periodic paralysis , LQT7)

Rare. Autosomal dominant transmission or sporadic cases. Association of a particular form of periodic paralysis, prolongation of the QT interval and ventricular arrhythmias. This form of familial periodic paralysis is sensitive to potassium. The congenital prolongation of QT is due to a mutation of the KCNJ2 gene (7q23) regulating the subunit 'a' of the potassium channel Kir2.1. It is  defined as type 1 if there is a mutation of the KCNJ2 gene (60 % of cases), and type 2 in the absence of this mutation.

Attacks of muscle weakness of hypokaliemic type  (after a prolonged rest or a rest following an important effort) associated with chronic ventricular arrhythmias. Ventricular extrasystoles worsening with effort, risk of syncope and sudden death.

Facial dysmorphism: mandibular hypoplasia with hypoplasia of the malar bones, hypertelorism, cleft palate, micrognathia. Small stature, clinodactyly and/or syndactyly, scoliosis. More rarely: bicuspid aortic valve, coarctation of the aorta or pulmonary artery stenosis.

Anesthetic implications: 

Mandibular hypoplasia with retrognathism: risk of difficult intubation. See congenital long QT syndromes. Check blood electrolytes: supplements of potassium in case of hypokalemia

References : 

 Young DA. 

Anesthesia for the child with Andersen’s syndrome. 

Pediatr Anesth 2005 ; 15 : 1019-20.

Updated: November 2019