Molecular autopsy: Evaluation of sudden unexpected death cases in terms of KCNQ1 genetic variation

Aim: Deaths occuring without a known disease and/or a known cause, deaths with non-lethal diseases are interpretated as sudden-unexpected-suspected deaths. Autopsy should always required to evaluate the cause of death. Some of the cases can be termed as negative autopsy since the cause of death can not be determined. This is one of the main interests of the future forensics. Molecular autopsies are one of the main practices of to reduce the negative autopsy ratios. Thus, post-mortem KCNQ1 genetic variation tests are done in sudden unexpected death cases. Material and methods: In this study 0 – 50 years old sudden-unexpected-suspected deaths autopsy cases were handled from the Morgue Department of the Adana Branch of the Forensic Medicine Council of Turkey. Samples taken from cases were evaluated pathologically, all medical and forensic history was examined and also "KCNQ1" genetic variation tests were done with blood samples taken into EDTA vials in our Department. Results: This study included 47 cases of 42 sudden unexpected death cases and 5 control group. Cases of 0 – 50 age group were included in sudden-unexpected death cases. 15 of 42 cases were between 40 – 50 age group and number of cases were increasing with age. 29 of cases (% 69) were male while 13 (% 31) were female. Evaluation of body-mass index of cases were done with World Health Organization Body-Mass İndex Classification. Normal weighted cases were the most common with 21 cases (% 50). Obesity-risk evaluation couldn't be done because our cases were not chosen randomly among all cases. All cases were distributed according to death locations. 17 cases had died (% 45,9) at home. Death location records of 5 cases couldn't be found. Pathological examinations of all cases were done (Myocardium-Coronary Artery and Cardiac Conduction System). Hematoxylin eosin staining method used during pathological examinations. We had identified fibrosis and fatty change appearances in SA node of 9 cases (% 21,4) and AV node of 13 cases (% 30,9) especially in conduction tissue examinations. As the result of KCNQ1 genetic analysis of cases, we identified sequence variations in 1638th nucleotid of exon 13 and 1986th nucleotid of exon 16. Although sequence variations identified in our study was interpreted as mutations in several studies, we believe that studies should be made in larger series and more primers should be used for realistic interpretations. Conclusion: Cases with conduction system pathology and sequence variations of KCNQ1 genetic analysis shows that we are in need of these tests among routine practice to reduce negative autopsy ratios. European Cardiovascular Pathology Assosication recommends not to finalise an autopsy without genetic analysis. These new methods and use of molecular autopsy will sure reduce the negative results and will explain the cause of deaths to us. Genetic analysis will give us the opportunity to explain the cause of deaths and the precautions that has to be taken for both justice and the relief of the families.