Use of fetal nuchal translucency in the first trimester to predict single‐gene disorders

Abstract

To assess the predictive value of fetal nuchal translucency (NT) measurement in the prenatal diagnosis of single-gene disorders. From January 1996 to December 2006, fetal NT was prospectively measured before chorionic villi sampling in 169 pregnancies at high risk for a single-gene disorder at 11 to 13 weeks of pregnancy. No differences were found between the 63 affected and 116 nonaffected fetuses in pregnancy demographic characteristics, in mean NT measurements, expressed either in millimetres [1.8 (95% CI:1.6-1.9) vs 1.7 (95% CI:1.6-1.8)] or in multiples of the median [1.19 (95%CI: 1.04-1.35) vs 1.14 (95%CI: 1.05-1.23)], or in median NT. The percentage of increased NT above the 95(th) percentile was similar for affected (9.5%) and nonaffected (11.2%) fetuses. Not all single-gene disorders are associated with enlarged NT, therefore NT cannot be regarded as a generic marker for single-gene disorder but only for a limited number of these conditions.