Molecular diagnosis in a child with sudden infant death syndrome

Although sudden infant death syndrome (SIDS) has been associated with long QT syndrome-a genetic disorder that causes arrhythmia-a causal link has not been shown. We screened genomic DNA from a child who died of SIDS and iden tified a de-novo mutation in KVLQT1, the gene most frequently associated wi th long QT syndrome. This mutation (C350T) had already been identified in a n unrelated family that was affected by long QT syndrome. These results con firm the hypothesis that some deaths from SIDS are caused by long QT syndro me and support implementation of neonatal electrocardiographic screening.