Genetic assessment following increased nuchal translucency and normal karyotype

Abstract

OBJECTIVE: The objective of this study was to assess the first formal approach for monitoring genetic/developmental syndromes associated with the presence of an increased nuchal translucency (NT) thickness (>3 mm) in the first trimester of pregnancy. METHODS: Multiple technologies-a DNA chip using the APEX technology, qPCR, microfluidic PCR, and sequencing-were applied to assay 310 mutations across five conditions-Noonan syndrome, congenital adrenal hyperplasia, spinal muscular atrophy (SMA), DiGeorge syndrome, and Smith-Lemli Opitz syndrome. RESULTS: We report the results of assessing the first 120 patients in which 8 cases of Noonan syndrome were detected as well as an unusually high rate of heterozygosity for SMA. CONCLUSION: While testing for Noonan syndrome in association with increased NT appears warranted, the reported association of the remaining four genetic syndromes is likely to be weak and possibly insignificant.