A mitochondrial DNA polymorphism associated with cardiac arrhythmia investigated in sudden infant death syndrome.
OBJECTIVE
Long QT syndrome (LQTS) has been shown to be the cause of death in some cases originally diagnosed as sudden infant death syndrome (SIDS). Such cardiac arrhythmias have also been noted in families with mitochondrial disease, and studies indicate that mitochondrial disease could be involved in SIDS. This makes the mtDNA polymorphism T3394C interesting, as a previous study has shown it to be associated with electrocardiographic (ECG) changes after exercise in a family with LQTS, where some members harboured a KCNH2 mutation.


METHODS
A total of 245 SIDS cases and 176 control cases.


METHODS
DNA was prepared from blood/tissue samples. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were performed to search for the mtDNA polymorphism and KCNH2 mutation. Differences were confirmed by sequencing.


RESULTS
The T3394C polymorphism was found in 3 pure SIDS cases (1.5%), 2 borderline SIDS cases (4.4%), 1 case of explained death (1.6%) and 2 living control cases (1.8%) (p = 0.62). The KCNH2 mutation was not found in cases or controls.


CONCLUSIONS
The mtDNA polymorphism studied was found in a small number of SIDS cases and the frequency did not differ statistically from control subjects, making an association with increased SIDS risk unlikely.
Arnestad
Marianne
M
Institute of Forensic Medicine, University of Oslo, Norway. marianne.arnestad@medisin.ui.no
Opdal
Siri Hauge
SH
Vege
Ashild
A
Rognum
Torleiv Ole
TO
D016022:Case-Control Studies; D002675:Child, Preschool; D004272:DNA, Mitochondrial / Q000235:genetics*; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008133:Long QT Syndrome / Q000235:genetics; D008297:Male; D009154:Mutation / Q000235:genetics*; D009245:NADH Dehydrogenase / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D013398:Sudden Infant Death / Q000235:genetics*
D004272:DNA, Mitochondrial; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; D009245:NADH Dehydrogenase; C000606913:KCNH2 protein, human; C515075:NADH dehydrogenase subunit 1, human