[Linkage analysis in a Japanese long QT syndrome family]

Romano-Ward syndrome is an autosomal dominant trait disease, which is characterized by QT prolongation and normal hearings and shows predisposal to sudden death from cardiac arrhythmia. Recently, Keating et al. reported that Harvey ras-1 locus (H-ras-1) was closely linked to long QT syndrome (LQTS), being located on the short arm of chromosome 11. In this study we have examined a three-generation Japanese family whose members had recurrent fainting with prolongation of the QT interval on electrocardiogram. Using the H-ras-1 probe as DNA marker, we could not determine that the H-ras-1 gene was linked to LQTS. LQTS seems to be a genetically heterogeneous disease. Further study is needed to clarify the chromosomal location of the LQTS.