Analysis of ALDH1A2, CYP26A1, CYP26B1, CRABP1, and CRABP2 in human neural tube defects suggests a possible association with alleles in ALDH1A2

BACKGROUND Vitamin A (retinol), in the form of retinoic acid (RA), is essential for normal development of the human embryo. Studies in the mouse and zebrafish have shown that retinol is metabolized in the developing spinal cord and must be maintained in a precise balance along the anteroposterior axis. Both excess and deficiency of RA can affect morphogenesis, including failures of neural tube closure. METHODS We chose to investigate 5 genes involved in the metabolism or synthesis of RA, ALDH1A2, CYP26A1, CYP26B1, CRABP1, and CRABP2, for their role in the development of human neural tube defects, such as spina bifida. RESULTS An association analysis using both allelic and genotypic single‐locus tests revealed a significant association between the risk for spina bifida and 3 polymorphisms in the gene ALDH1A2; however, we found no evidence of a significant multilocus association. CONCLUSIONS These results may suggest that polymorphisms in ALDH1A2 may influence the risk for lumbosacral myelomeningocele in humans. Birth Defects Research (Part A), 2005. © 2005 Wiley‐Liss, Inc.