RESUMEN
<p><b>OBJECTIVE</b>To investigate the clinical features of unexpected sudden death (SUD) clustered in families in Yunnan province.</p><p><b>METHODS</b>This retrospective study analyzed the clinical features of SUD occurred between July to September 2005 in 7 families in Yunnan province.</p><p><b>RESULTS</b>All 16 SUD patients shared common clinical features such as fatigue and repeated syncope and one group of SUD patients (n = 8 from 4 families) presented with the gastric intestinal tract manifestations including nausea, vomiting, abdominal pain and diarrhea with suspected dietary history and abnormal laboratory enzyme findings (GOT/GPT, CK/CKMB, LDH/LDH1 etc.). In SUD patients without gastric intestinal tract manifestations (n = 8 from 3 families), there were no clear symptoms before death and repeated ventricular tachycardia and ventricular fibrillation were recorded in one survivor. There was no clear evidence for the involvements of hereditary and infectious factors for observed SUD.</p><p><b>CONCLUSION</b>The reason for the unexpected sudden death clustered in 7 families in Yunnan remains unclear. Repeated syncope and fatigue served as the common clinical features in the presence or absence of gastric intestinal tract manifestations in all SUD cases. Further studies are needed to clarify the pathology and detailed clinical manifestations of SUD occurred in this area.</p>