Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA.
Genet Med. 2013 Sep;15(9):698-705. doi: 10.1038/gim.2013.34. Epub 2013 Apr 4.
Advanced maternal age and altered recombination are known risk factors for Down syndrome cases due to maternal nondisjunction of chromosome 21, whereas the impact of other environmental and genetic factors is unclear. The aim of this study was to investigate an association between low maternal socioeconomic status and chromosome 21 nondisjunction.
Data from 714 case and 977 control families were used to assess chromosome 21 meiosis I and meiosis II nondisjunction errors in the presence of three low socioeconomic status factors: (i) both parents had not completed high school, (ii) both maternal grandparents had not completed high school, and (iii) an annual household income of <$25,000. We applied logistic regression models and adjusted for covariates, including maternal age and race/ethnicity.
As compared with mothers of controls (n = 977), mothers with meiosis II chromosome 21 nondisjunction (n = 182) were more likely to have a history of one low socioeconomic status factor (odds ratio = 1.81; 95% confidence interval = 1.07-3.05) and ≥2 low socioeconomic status factors (odds ratio = 2.17; 95% confidence interval = 1.02-4.63). This association was driven primarily by having a low household income (odds ratio = 1.79; 95% confidence interval = 1.14-2.73). The same statistically significant association was not detected among maternal meiosis I errors (odds ratio = 1.31; 95% confidence interval = 0.81-2.10), in spite of having a larger sample size (n = 532).
We detected a significant association between low maternal socioeconomic status and meiosis II chromosome 21 nondisjunction. Further studies are warranted to explore which aspects of low maternal socioeconomic status, such as environmental exposures or poor nutrition, may account for these results.
高龄产妇和染色体 21 重组异常是唐氏综合征病例的已知风险因素，这是由于母源染色体 21 不分离所致，而其他环境和遗传因素的影响尚不清楚。本研究旨在探讨低社会经济地位与染色体 21 不分离之间的关联。
利用 714 例病例和 977 例对照家庭的数据，评估了三种低社会经济地位因素存在的情况下，染色体 21 减数分裂 I 和减数分裂 II 不分离错误：（i）父母双方均未完成高中学业，（ii）母亲的外祖父母均未完成高中学业，以及（iii）家庭年收入<$25000。我们应用了逻辑回归模型，并进行了包括母亲年龄和种族/民族在内的混杂因素调整。
与对照组（n = 977）的母亲相比，发生染色体 21 减数分裂 II 不分离的母亲（n = 182）更有可能具有一个低社会经济地位因素的病史（比值比 = 1.81；95%置信区间 = 1.07-3.05）和≥2 个低社会经济地位因素（比值比 = 2.17；95%置信区间 = 1.02-4.63）。这种关联主要是由家庭收入低驱动的（比值比 = 1.79；95%置信区间 = 1.14-2.73）。尽管样本量更大（n = 532），但在母源减数分裂 I 错误中未发现具有统计学意义的相同关联（比值比 = 1.31；95%置信区间 = 0.81-2.10）。
我们发现低社会经济地位与染色体 21 减数分裂 II 不分离之间存在显著关联。需要进一步研究以探讨低社会经济地位的哪些方面，例如环境暴露或营养不良，可能导致这些结果。
