INTRODUCTION: Recent advances in molecular genetic research have provided new 
insights into severe ventricular arrhythmias related to channelopathies.
CASE REPORT: A case of Andersen's syndrome followed during fourteen years is 
reported. This rare familial periodic paralysis is characterized by its 
association with dysmorphic features (micrognatia) and ventricular arrhythmias.
COMMENTS: Andersen's syndrome has been attributed to a mutation in the KCNJ2 
gene which is involved not only in stabilizing cardiac rhythm, but also in 
modulating the excitability of skeletal muscle and in morphogenesis. This 
disease must be distinguished from hyperkalemic periodic paralysis due to a 
mutation in the skeletal muscle sodium channel gene (SCN4A) and from hypokalemic 
periodic paralysis related to dihydropyridine receptor mutation (CACNL1A3). 
Furthermore, it may not be confused with others rhythmic channelopathies (long 
QT syndromes, catecholaminergic polymorphic ventricular tachycardia and 
Brugada's syndrome).