Plakophilin-2 (PKP2) variants could produce a phenotype of Brugada syndrome (BrS), which seems to be most likely the same allelic disorder as some sudden unexplained nocturnal death syndrome (SUNDS). All coding regions of PKP2 gene in 119 SUNDS victims were genetically screened using PCR and direct Sanger sequencing methods. Three novel mutations (p.Ala159Thr, p.Val200Val, and p.Gly265Glu), one novel rare polymorphism (p.Thr723Thr), and eight reported polymorphisms were identified. A compound mutation (p.Ala159Thr and p.Gly265Glu) and a rare polymorphism (p.Thr723Thr) were found in one SUNDS case with absence of the cardiomyopathic features. The detected compound mutation identified in this first investigation of PKP2 genetic phenotype in SUNDS is regarded as the plausible genetic cause of this SUNDS case. The rare incidence of PKP2 mutation in SUNDS (1%) supports the previous viewpoint that SUNDS is most likely an allelic disorder as BrS.