A case of sudden unexpected natural death in a young adult male from the north-eastern part of Thailand with clinical non Lai-Tai disease, but pathologic feature of mitral valve prolapse is discussed. The approach to the postmortem examination of the mitral valve is reviewed. Because of the sudden nature of this
death, this entity is more commonly seen in Medico-legal Medicine populations than in hospital autopsies.

Keywords : Non Lai Tai disease, Mitral valve prolapse, Autopsy