Testing for 22q11 microdeletion in 146 fetuses with nuchal translucency above the 99th percentile and a normal karyotype.

The aim of this study was to examine the value of testing for a 22q11 microdeletion in fetuses with nuchal translucency (NT) above the 99th percentile (>3.5 mm). A 22q11 microdeletion results in the development of 22q11 deletion syndrome, a spectrum of disorders also known as DiGeorge/Velocardiofacial syndrome. A total of 146 pregnancies met the inclusion criteria of NT >3.5 mm between 11+2 and 13+6 weeks' gestation, no structural malformation and normal karyotype. Chorionic villi samples were tested with either multiplex ligation-dependent probe amplification (MLPA) or fluorescent in situ hybridization (FISH) analysis for 22q11 microdeletion. None were diagnosed with the microdeletion. The estimated prevalence of 22q11 microdeletion in these otherwise normal fetuses with increased NT is below 2.7%.