Prevalence of craniorachischisis in a Texas-Mexico border population.

Background: The most severe neural tube defect (NTD), craniorachischisis, is characterized by anencephaly confluent with spina bifida open from the cervical to the lumbar region. We describe the prevalence of craniorachischisis among the Texas-Mexico border population during the period 1993-1999.

Methods: An active surveillance system identified all clinically apparent NTD-affected fetuses and infants born to mothers residing and delivering in any of the 14 Texas-Mexico border counties. Craniorachischisis cases included live-born, stillborn, and therapeutic abortions.

Results: A total of 16 craniorachischisis cases were identified for a total prevalence of 0.51 per 10,000 live births (Mexican American prevalence, 0.52 per 10,000) and a prevalence of 0.28 per 10,000 live births for cases of 20 weeks gestation or greater.

Conclusions: The prevalence of craniorachischisis was higher than that reported in Atlanta (0.1 per 10,000 live births), but much lower than that reported in Northern China (10.7 per 10,000 births). In this high NTD prevalence region, it is possible that a multiplicity of risk factors, mostly related to poverty, contribute to a high prevalence of craniorachischisis.