Abstract A description is given of an 8-year-old girl with the syndrome of Jervell and Lange Nielsen consisting of congenital deafness, prolonged Q-T time in the ECG, and attacks of unconsciousness. In addition there were extrasystoles, ventricular tachycardia, ventricular fibrillation, and atrial flutter. The syncopes proved to be based on circulatory insufficiency as a result of ventricular fibrillation. The child suffered in addition from diabetes insipidus on the basis of a disturbance in renal function, and hyperuricemia was repeatedly found. The girl died as a result of an attack of ventricular fibrillation, after an initial period of considerable clinical improvement upon Benemid medication. It is suggested that the recently described combination of Q-T prolongation in the ECG and syncopal attacks as a result of ventricular fibrillation must be regarded as the same genotypical entity. The possibility is mentioned that this case may have presented a symptom complex in association with hyperuricemia.