Sudden Unexplained Nocturnal Death Syndrome in Southern China

Abstract

Based on autopsy data collected in Southern China from [2001][2002][2003][2004][2005][2006], 975 cases of sudden unexplained nocturnal death syndrome (SUNDS) were surveyed. Genetic screening of SCN5A, the gene encoding the voltage dependent cardiac Na channel, was performed in 74 available SUNDS cases. The annual occurrence rate of SUNDS in the area was estimated to be 1 per 100,000 people. 80.6% of deaths occurred between the ages of 21 to 40 years and the case number peaked at age 30 years. In 75.4% of cases where witnesses were present, victims died in their sleep between 11 PM and 4 AM and many showed abrupt respiratory distress shortly preceding death. The monthly distribution of emergency fever cases in the area during the same period was positively correlated to that of SUNDS cases (r s = 0.611, P = 0.0025). Four polymorphisms in SCN5A were identified in both SUNDS and control groups. Compared with controls, the allele frequency of C5457 and C3666+69 were significant higher in SUNDS (P<0.005) while the genotypes of both 5457CC (P=0.012, OR=2.0, 95% CI=1.3-3.2) and 3666+69CC (P=0.004, OR=2.1, 95% CI=1.3-3.3) in SUNDS cases were significantly higher. This is the first report of an epidemiological survey and SCN5A gene screening in SUNDS in the Han population of China. The genotypes of 5457CC and 3666+69CC in SCN5A gene may be Chinese SUNDS susceptible polymorphisms.

The global distribution of the p.R1193Q polymorphism in the SCN5A gene

“…No significant differences were previously identified in the allele frequencies of the p.R1193Q mutation between SUNDS cases and control groups in southern China, with allele A frequencies of 0.061 and 0.048, respectively [10]. The frequency of allele A in Japanese patients with Brugada syndrome was previously reported to be 0.0515 [26], which is consistent with the frequencies observed in the Japanese population in the present study.…”

“…The allelic frequency of the p.R1193Q polymorphism has been investigated in several populations, suggesting that the p.R1193Q polymorphism is common in Asian populations [9,10]. In order to elucidate the geographical distribution of the p.R1193Q polymorphism, we herein investigated more than 4,000 individuals from Asian, European, and African populations.…”

Postmortem molecular analysis of KCNQ1, KCNH2, KCNE1 and KCNE2 genes in sudden unexplained nocturnal death syndrome in the Chinese Han population

“…The ages did not significantly differ between the SUNDS cases and the control group (P > 0.05). All SUNDS decedents were sporadic and were negative in family history of sudden death and cardiac pathology according to our investigation as previously reported [1].…”

Association of common and rare variants of SCN10A gene with sudden unexplained nocturnal death syndrome in Chinese Han population

“…The inclusion criteria for SUNDS were as follows [10,15]: (1) a southern Chinese Han male greater than or equal to 15 years old; (2) apparently healthy without any previously significant disease; (3) experiencing symptoms of moaning, apnea, and abrupt tic of limbs prior to the sudden unexpected death at night during sleep; and (4) negative postmortem findings from the standard forensic autopsy, histopathology examination, toxicological analysis, and death-scene investigation. Twenty-two consecutive BrS cases from 2006 to 2015 were collected from the First Affiliated Hospital of Sun Yat-sen University, as we previously reported, to screen SCN10A variants [23].…”

“…The annual incidence of SUNDS has been reported to be as high as 43 per 100,000 people aged 20-40 years in the Philippines [9] and 38 per 100,000 people aged 20-49 years in Thailand [3]. In southern China, the incidence is about one to two per 100, 000 people per year [10,11]. So far, SUNDS has remained an autopsy negative enigma with uncertain etiology.…”