Malformations.

The brain and upper spinal cord form from the neural plate during primary neurulation beginning at 22 days' gestation; the sacral spinal cord forms from the tail bud during secondary neurulation [1]. The various classifications of neural tube defects (NTDs) is complex and somewhat contradictory [2]. Practically, they can be considered as "open" (e.g., anencephaly, craniorachischisis, myelomeningocele) or "closed" (e.g., encephaloceles, meningoceles, split spinal cord). There are several pathoetiologies [3]. Folic acid supplementation before and during early pregnancy prevents most NTDs [3,4]. A mutant mouse model for NTD, Splotch, is being used to define the mechanism of teratogenesis by folate insufficiency [5]. A second mutant, curly tail, has an NTD that responds to myoinositol [6]. [ABSTRACT FROM AUTHOR]