Recurrence risks for neural tube defects in siblings of patients with lipomyelomeningocele.

Purpose: Neural tube defects (NTDs) are a group of widely varying congenital malformations resulting from incomplete or improper fusion of the neural tube during embryonic development. NTDs are traditionally classified by the presence or absence of a layer of skin covering the spinal defect. Although a genetic component has been well established in the etiology of open NTDs, studies examining the genetics of closed NTDs such as lipomyelomeningocele are rare.