Van Rootselaar F J
Med Hypotheses. 1993 Jul;41(1):78-82. doi: 10.1016/0306-9877(93)90039-s.
The incidence of neural tube defects (NTDs) shows a seasonal variation; and incidence as well as female/male ratio show a relation with latitude. The interrelation of these phenomena is presented as a mathematical model, which has a 'predictive' value, and is an instrument in estimating the local gene frequency. The model offers a simple explanation of the conundrum why the double X-chromosome has a variable influence on the sex ratio. UV light and the herpes virus fit in this model as related causative factors of NTDs.
神经管缺陷（NTDs）的发病率呈现季节性变化；发病率以及男女比例与纬度有关。这些现象之间的相互关系以数学模型呈现，该模型具有“预测”价值，是估计当地基因频率的一种工具。该模型对双X染色体为何对性别比例有可变影响这一难题提供了一个简单解释。紫外线和疱疹病毒作为神经管缺陷的相关致病因素符合该模型。
