Abstract
Aim: To address the research question: "What are the pathophysiologic mechanisms underlying spina bifida, anencephaly and craniorachischisis?".
Background: During vertebrate embryonic development, serious congenital abnormalities known as neural tube defects (NTDs) can arise when the process of neurulation is disrupted and the neural tube fails to fuse correctly. Spina bifida, anencephaly and craniorachischisis represent three distinct NTDs which develop depending upon which of three closure sites in the neural tube fails to close. Despite the well-established benefits of folic acid supplementation before and during the earliest stages of pregnancy to reduce NTD risk, folate-resistant NTDs continue to be a significant concern. Ongoing research is required to investigate the pathophysiologic mechanisms underlying NTDs which are not preventable by folic acid supplementation, to aid in the development of targeted interventions to reduce NTD prevalence.
Methodology: An integrative review was conducted using the electronic databases Medline, Emcare and the Cumulative Index to Nursing and Allied Health Literature. Data was extracted from studies which satisfied inclusion criteria and met quality standards. Data from eligible studies was then analyzed in accordance with a constant comparative approach, involving the iterative and systematic reduction of the dataset into subcategories while distinct patterns and relationships were continuously synthesized (Glaser and Strauss, 1967).
Results: Thirteen studies were analysed in this review. These studies highlighted (a) an association between planar cell polarity (PCP) pathway disruption and NTDs, (b) an association between copy number variants and NTDs, and (c) an association between immune-pathway disruption and NTDs.
Discussion: Recent advances in sequencing technology have facilitated a more in-depth analysis of possible mechanisms underlying NTDs. A number of these mechanisms likely work in conjunction to cause NTDs, making its pathophysiology complex and multigenic. Key mechanisms implicated in NTD risk include disruptions to the PCP pathway, dysregulated DNA repair and altered DNA methylation.
Conclusions: The current review presents recent research findings regarding the pathophysiologic mechanisms underlying spina bifida, anencephaly and craniorachischisis. Increased insight on this topic has implications for the development of targeted interventions to reduce NTD prevalence. In addition, developing understanding surrounding NTD etiology within the nursing field will enhance clinical knowledge, awareness, health education and care for NTD-affected individuals and their families.