A precision modeling pipeline for rapid characterization of SIDS associated genetic variants
Authors: Memos Nicoletta , Lanza Denise , Heaney Jason , Ray Russell 
Published: May 2023

Sudden Infant Death Syndrome (SIDS) is the leading cause of infant death under the age of one year of age, taking the lives of more than 1,400 infants annually. SIDS etiology remains vastly unknown but is best explained via a triple risk model that proposes SIDS occurs in a vulnerable infant during a critical developmental period when triggered by an external stressor. In SIDS it is hypothesized that there is failure in arousal followed by failure in the protective auto-resuscitation reflex; a defense mechanism for an infant experiencing severe hypoxia, apnea, and bradycardia, that promotes deep gasping to attempt to restart breathing. Increasing numbers of SIDS case studies reveal associations with genetic variants and abnormal biomarkers though it is unclear whether these variants are causal. We developed a rapid pipeline for precision genetic modeling and high-throughput functional testing to elucidate potential mechanisms underlying SIDS associated gene variants and biomarker perturbations. Our pipeline utilizes CRISPR/Cas9 gene editing in mouse oocytes to rapidly produce genetic models followed by high-throughput assessment of the auto-resuscitation reflex using our recently developed closed loop robotic neonate cardio-respiratory phenotyping platform. As a demonstration of our concept, we modeled butyrylcholinesterase (BChE) loss of function in neonatal auto-resuscitation. Recently a case study (PMID:35533499) identified a broad association between reduced blood BChE activity and SIDS cases, yet the potential functional relationship between BChE and respiratory regulation is underexplored. To gain mechanistic insight into BChE and neonate breathing, we aimed to rapidly develop a de novo model of BChE loss of function and test the outcomes. Using mouse oocyte based CRISPR/Cas9 editing, we deleted exon 2 of BChE. First generation BChE null mice were ready for testing in 16 weeks and assayed for auto-resuscitation on our novel testbed, leveraging multiple systems for near simultaneous testing of all pups in a litter by a single investigator. Postnatal day 7-8 mice were exposed to 3% CO2 and 97% N2stimuli to induce a state of hypoxia resulting in detection of bradycardia, initial hyperventilation, hypoventilation, and apnea followed by restoration of room air conditions to facilitate the auto-resuscitation reflex and cardio-respiratory recovery. Mice were exposed to repeated bouts of anoxic challenges until death occurred. Preliminary data suggest that perturbations in BChE expression results in alterations in the neonate auto-resuscitation reflex and survival. Results validate our rapid precision modeling pipeline to assess SIDS associated genetic variants and highlight a potential role of BChE in SIDS etiology with implications in future development of targeted interventions. Precision Core Funding U54 OD030165, NIH/NHLBI R01HLN161142-01 and NIH/NHLBI R01HL130249-07 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.