Dominant-inherited hypokalemic periodic paralysis in a large Chinese family

Familial hypokalemic periodic paralysis (HoPP) is a rare condition among Ch inese. We studied a large Chinese family (48 members in six generations) wi th dominant-inherited HoPP, using incidental tracing of family history of a proband who presented with the typical features of HoPP. Fifteen family me mbers were found to have the disease. We found the familial type of HoPP to differ from the sporadic type in Taiwan, in that the familial type has an equal gender distribution, earlier onset of paralytic attacks, and more sev ere clinical features in both frequency and extent. When these patients wer e compared with Caucasian families, the common features were the involvemen t of the respiratory and the bulbar muscles, and the eye muscles in Chinese patients. Cold-induced attacks and permanent muscle weakness were not comm on in Chinese subjects. Age and history of paralytic attacks were not the m ajor determinants for the development of permanent muscle weakness. Two fam ily members died during attacks because of severe involvement of the respir atory and bulbar muscles.