Sudden infant death syndrome (SIDS)-the sudden and unexplained death of a seemingly healthy infant, <1 year old-may be associated with abnormalities in the brain regions that underlie breathing and arousal during sleep. While post-mortem studies suggest abnormalities in SIDS infants\' brainstems, there are no studies of these infants\' brainstem function before death. One way to assess the function of the brainstem is with auditory brainstem response (ABR), a routine hearing-screening method that noninvasively measures the brainstem\'s response to sound. We hypothesize that anomalies in newborns\' ABR measures may predict SIDS. Indeed, previous studies identified abnormalities in ABR characteristics in small samples of near-miss SIDS infants hospitalized for infant apnea syndrome. However, there is a need to examine the ABRs of infants who died of SIDS. Therefore, in the current study, we propose integrating two secondary datasets to examine newborns\' ABRs (N = 156,972), including those who later died of SIDS (n = ~42; .27 out of every 1000 infants), using existing archived records of neonatal ABR results from a sample of newborns born in Florida. We hypothesize that infants who die from SIDS are more likely than non-SIDS infants to have abnormal ABRs as newborns. Understanding the association between SIDS and ABR may facilitate more accurate identification of an infant\'s risk for SIDS at birth, enabling increased monitoring, which may facilitate interventions and improve survivorship.

A female neonate born with normal Apgar scores at 38+2 weeks of gestational age unexpectedly passed away within less than 30 hours after birth. The situation mirrored her brother\'s earlier demise within 24 hours post-delivery, suggesting a possible genetic disorder. Gross examination revealed widespread cyanosis and distinct yellowish changes on the cardiac ventricles. Histopathological examination disclosed lipid accumulation in the liver, heart, and kidneys. Tandem mass spectrometry detected elevated levels of 10 amino acids and 14 carnitines in cardiac blood. Trio-whole genome sequencing (Trio-WGS) identified the SLC25A20 c.199-10T>G mutation associated with carnitine-acylcarnitine translocase disease (CACTD), a type of fatty acid oxidation disorders (FAODs) with a potential for sudden death. Further validation of gene expression confirmed the functional deficiency of SLC25A20, ultimately diagnosing CACTD as the underlying cause of the neonate\'s demise. This case highlights the importance of prenatal metabolic and genetic screening for prospective parents and emphasizes the need for forensic doctors to integrate metabolomic and genomic investigations into autopsies for suspected inherited metabolic diseases.

OBJECTIVE: The common differentially expressed mRNAs in brain, heart and liver tissues of deceased sudden infant death syndrome (SIDS) and infectious sudden death in infancy (ISDI) confirmed by autopsy was screened by bioinformatics to explore the common molecular markers and pathogenesis of SIDS and ISDI.
METHODS: The datasets of GSE70422 and GSE136992 were downloaded, the limma of R software was used to screen differentially expressed mRNA in different tissue samples of SIDS and ISDI decedents for overlapping analysis. The clusterProfiler of R software was used to conduct gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The protein-protein interaction (PPI) network was constructed by STRING database, while the hub gene was screened by cytoHubba plug-in.
RESULTS: Compared with the control group, there were 19 significant differentially expressed genes in the tissue samples of SIDS and ISDI decedents, among which 16 in the heart tissue and 3 in the liver tissue, and the astrotactin 1 (ASTN1) gene expression difference in the heart tissue was most significant. The PPI network identified Ras homolog family member A (RHOA), integrin subunit alpha 1 (ITGA1), and H2B clustered histone 5 (H2BC5) were hub genes. The analysis of GO and KEGG showed that differentially expressed genes were enriched in the molecular pathways of actin cytoskeleton regulation, focal adhesion and response to mycophenolic acid.
CONCLUSIONS: ASTN1, RHOA and ITGA1 may participate in the development of SIDS and ISDI. The enrichment of differentially expressed genes in immune and inflammatory pathways suggests a common molecular regulatory mechanism between SIDS and ISDI. These findings are expected to provide new biomarkers for molecular anatomy and forensic identification of SIDS and ISDI.
目的: 应用生物信息学方法筛选出经尸体检验确诊的婴儿猝死综合征（sudden infant death syndrome，SIDS）和婴儿感染性猝死（infectious sudden death in infancy，ISDI）死者脑、心脏和肝组织中共有的差异表达mRNA，探讨SIDS与ISDI的共有分子标记和发生机制。方法: 下载GSE70422、GSE136992数据集，用R软件limma包筛选SIDS和ISDI死者不同组织样本中差异表达的mRNA，进行重叠分析，并用R软件clusterProfiler包进行基因本体论（gene ontology，GO）和京都基因和基因组数据库（Kyoto Encyclopedia of Genes and Genomes，KEGG）富集分析，使用STRING数据库构建蛋白质-蛋白质相互作用（protein-protein interaction，PPI）网络，基于cytoHubba插件筛选hub基因。结果: 与数据集中的对照组相比，SIDS和ISDI死者组织样本中有19个显著的共同差异基因，其中心脏组织中16个、肝组织中3个，心脏组织星形肌动蛋白1（astrotactin 1，ASTN1）基因表达差异最显著。PPI网络确定了Ras同源基因家族成员A（ras homolog family member A，RHOA）、整合素亚单位α1（integrin subunit alpha 1，ITGA1）和H2B簇状组蛋白5（H2B clustered histone 5，H2BC5）是hub基因。GO和KEGG分析结果表明，共同差异基因富集在肌动蛋白细胞骨架的调节、黏着斑及对霉酚酸的反应等分子通路中。结论: ASTN1、RHOA和ITGA1可能参与SIDS与ISDI的发生发展。共同差异基因富集在免疫与炎症反应相关通路中，说明SIDS与ISDI在免疫与炎症反应方面可能存在共同的分子调控机制。这些发现有望为SIDS与ISDI的分子解剖和法医学鉴定提供新的生物标记。.

The aim was to study whether non-combustible nicotine (Swedish snuff) use in pregnancy is associated with elevated risk of post neonatal mortality, Sudden Infant Death Syndrome (SIDS), and Sudden Unexpected Infant Death (SUID) and to study how cessation before the antenatal booking influenced these risks.
This was a population-based register study of all infants with information on tobacco exposure in early pregnancy born in Sweden 1999-2019, n = 2,061,514. Self-reported tobacco use in early pregnancy was categorized as nonuse, snuff use, and moderate and heavy smoking. Multiple logistic regression models were used to estimate crude and adjusted odds ratios (aORs) with 95% confidence intervals (CIs).
Maternal snuff use was associated with increased risks of post neonatal mortality, SIDS, and SUID. The risks of snuff use and moderate smoking were of similar magnitude. Heavy smoking was associated with the highest risks. Cessation of smoking and snuff use before the antenatal booking was associated with lower risks of SIDS and SUID compared to that of continuous usage.
Maternal snuff use was associated with increased risks of post neonatal mortality, SIDS, and SUID. Nicotine is the common substance in cigarette smoke and snuff. These findings support the hypothesis that nicotine contributes to an elevated risk of SIDS.
Maternal snuff use and smoking in early pregnancy were associated with increased risks of post neonatal mortality, SIDS, and SUID. Cessation of smoking and snuff use before the first antenatal visit was associated with reduced risks of SIDS and SUID. The common substance in cigarette smoke and snuff is nicotine. Our findings suggest that nicotine contributes to an elevated risk of SIDS and SUID. The implication of our findings is that all forms of nicotine should be avoided in pregnancy.

Thymic hypoplasia is a primary cellular immunodeficiency that causes susceptibility to serious infections leading to sudden death in infants. Some genetic disorders in humans could result in the evident permanent hypoplasia or occasional aplasia of the thymus at birth. However, determining the genetic etiology of thymic hypoplasia is challenging for the sudden infant death due to primary cellular immunodeficiency. In this study, in order to find the fundamental reasons for sudden death of infants with thymic hypoplasia, 5 infants with suspected thymic hypoplasia and 10 control infants were assessed, and the immunohistochemistry and DNA analysis were used to investigate whether the infants with thymic hypoplasia had DiGeorge syndrome (DGS) with copy number variations (CNVs) in 22q11.2 and other chromosomes. The results showed that the weight of the thymus was significantly lower than the normal except the case 4, and that all the infants had hypocalcemia and a significant decrease or even absence of the markers CD1a, CD2, CD3, CD4 and CD8, which are related to T-cell maturation. In addition, multiplex ligation-dependent probe amplification (MLPA) analysis showed that these infants carried CNVs in 22q11.2 and other associated chromosomes with deletion and duplication of 25 genes. The results of thymus weight, histopathology, molecular pathology and MLPA analysis suggested that DGS predominantly with thymic hypoplasia induced by CNVs caused the sudden death of these infants under various infections or other unexplained reasons, which may provide new insights into the diagnosis of sudden infant death and could help the parents of deceased infants to attach more importance of genetic screening and thymus ultrasound to reduce the postnatal mortality of the infant, and demonstrates the value of genetic diagnosis in the forensic pathology.

This retrospective study aimed to determine the epidemiological features of deaths caused by unintentional suffocation among infants in China.
The data used in this study were obtained from China\'s Under 5 Child Mortality Surveillance System (U5CMSS) from October 1, 2015, to September 30, 2016. A total of 377 children under 1 year of age who died from unintentional suffocation were included in the survey. Primary caregivers were interviewed individually using the Unintentional Suffocation Mortality among Children under 5 Questionnaire. EpiData was used to establish the database, and the results were analysed using SPSS 22.0.
Most (85.9%) unintentional infant suffocations occurred in rural areas, and 67.5% occurred in infants 0 to 3 months old. Among the primary caregivers of the infants, most (82.7%) had a junior middle school education or below, and 83.1% of them lacked unintentional suffocation first aid skills. Of the 377 unintentional suffocated-infant deaths, the causes of death were accidental suffocation and strangulation in bed (ASSB) (193, 51.2%), inhalation suffocation (154, 40.8%), other unintentional suffocation (6, 1.6%), and unknown (24, 6.4%). Among the infant deaths due to ASSB, overlaying (88.6%) was the most frequently reported circumstance. A total of 93.8% of cases reported occurred during co-sleeping/bed sharing with parents, and in 72.8% of the cases, the infants were covered with the same quilt as their parents. In our study, most inhalation suffocation deaths (88.3%) involved liquid food (such as breast milk and formula milk). A total of 80.5% of infant deaths reportedly occurred after eating; in 28.2% of those cases, the infants were held upright and patted by their caregivers, and 57.2% of them were laid down to sleep immediately after eating.
To reduce the occurrence of unintentional suffocation, local government should strengthen knowledge and awareness of unintentional suffocation prevention and safety among parents and caregivers. Additionally, health care providers should educate parents and caregivers about safety issues of unintentional suffocation, and relevant policies should be introduced to provide environments and activities that reduce the risk of suffocation, such as promoting the Safe to Sleep Campaign. It is important to enhance the focus on infant unintentional suffocation as a health issue.

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遗传学病因在婴儿猝死综合征（SIDS）的发生中起重要的作用，通过分子尸检可协助明确SIDS的遗传学病因。分子尸检的检测方法有多种，二代测序是目前最具前景的检测方法。既往通过分子尸检明确的SIDS遗传学病因主要分布于心脏离子通道病、心肌病、代谢性疾病、线粒体疾病等。同时分子尸检也仍存在一系列问题亟待解决。.

BACKGROUND: The etiology of sudden infant death syndrome (SIDS) remains an unsolved problem. The aim of this meta-analysis is to investigate the potential association between monoamine oxidase A (MAOA) promoter variable number tandem repeat (VNTR) polymorphism and SIDS risk.
METHODS: A systematic review and meta-analysis were conducted on studies from accessible electronic databases. Each VNTR variant was examined in each gender independently by comparing with the pooled results of other alleles.
RESULTS: A total of six independent case-control studies including 1022 SIDS cases and 1839 controls were enrolled in this meta-analysis. In both of the whole populations and Caucasian populations, male infants with the low-MAOA-expression alleles (2R+3R) were found to exhibit a statistically significant increased risk of SIDS, whereas those with a 4R allele exhibited a reduced risk of SIDS. Besides, an increased risk of SIDS was detected in male Caucasian infants with 2R or 3R alleles. However, none of the allele or genotype variants was associated with SIDS in female victims.
CONCLUSIONS: In male Caucasian infants, the low expression of MAOA promoter VNTR alleles (2R and 3R) is associated with an increased risk of SIDS, and the existence of the 4R allele could be regarded as a protective factor.

The association between air pollution and infant mortality has been inconsistently reported. A few studies have estimated short-term effects of air pollution on infants\' health. This population-based case-control study aimed to examine the potential effects of air pollution on sudden infant death syndrome (SIDS) in the post-neonatal period in Taiwan during 1997-2002. Each case of infant death was matched with 20 randomly selected sex-matched controls who were born on the same day and were still alive. We obtained 24-h measurements of air pollutants and meteorological factors in each case and control with 1- to 14-day lags from 55 air-quality monitoring stations. After controlling for potential confounders, conditional logistic regression analysis was performed to estimate effects of air pollutants on SIDS (n = 398) and respiratory death (n = 121) among neonates. In single- and multi-pollutant models, we found that 100-ppb increment in carbon monoxide (Odds Ratio = 1.04-1.07) and 10-ppb increment in nitrogen dioxide (Odds Ratio = 1.20-1.35) with 1- to 14-day lags were associated with significant increase in SIDS, although a significant relationship between air pollution and respiratory death was not determined in 1- to 14-day lags. Short-term carbon monoxide and nitrogen dioxide exposure were associated with significant increase in SIDS in the post-neonatal period, with latency estimated within days before death.