Andersen syndrome is a rare entity and comprises potassium sensitive periodic 
paralysis, ventricular arrhythmia, and an unusual facial appearance; syncope and 
sudden death have also been reported. The recognition of the characteristic face 
permits an early diagnosis in order to detect the severe systemic manifestations 
that are associated with this syndrome. The genetic defect is not linked to any 
other form of potassium sensitive periodic paralysis nor is it related to that 
of the long QT syndrome; nevertheless, a prolonged QT interval can be detected 
in a significant proportion of the cases. Sixteen cases of this syndrome have 
been described. We report on a three-generation family with 10 affected members. 
To our knowledge, this is the largest number of cases reported in one family. We 
noted some additional minor anomalies such as broad forehead and malar 
hypoplasia. Our patients had variable expression in the classical triad and of 
the severity of the systemic manifestations. Five of 8 affected studied members 
did not have a long QTc, which has been suggested as a constant finding in this 
syndrome.