Increased Nuchal Translucency (NT) is defined as an abnormal accumulation of fluid in the nuchal area, which is visualized as a thickened sonolucent area. It is a standardized measure obtained between 11 and 14 weeks of gestation to calculate the risk of a fetus being affected by a chromosomal aneuploidy. NT>3.5mm has been found to be associated with fetal chromosomal abnormalities and single-gene disorders as well as cardiac defects and other structural abnormalities in euploid and aneuploid fetuses. Proportionally as NT increases, even with a normal karyotype, there is a higher risk of adverse pregnancy outcomes such as miscarriage, intrauterine death, congenital heart defects and numerous other structural and genetic syndromes. There is not one single cause of increased NT, it is based on a complex and multifactorial process, linked to one or more embryonic processes. It has been shown that a persistently increased NT with a normal karyotype and aCGH has a 4-10% probability of being associated to Noonan Syndrome and/or other RASopathies using Whole Exome Sequencing (WES). However, the general tendency following detection of isolated enlarged NT in an euploid fetus is that most babies with normal detailed ultrasound examination and echocardiography will have uneventful outcomes.
The Igenomix Increased Nuchal Translucency Precision Panel can be used to make a directed and accurate prenatal differential diagnosis of increased nuchal translucency in patients with or without a normal karyotype ultimately leading to a better management and prognosis of the associated comorbidities. It provides a comprehensive analysis of the genes involved in this disease using next-generation sequencing (NGS) to fully understand the spectrum of relevant genes involved.
The clinical utility of this panel is:
Burger, N. B., Bekker, M. N., de Groot, C. J., Christoffels, V. M., & Haak, M. C. (2015). Why increased nuchal translucency is associated with congenital heart disease: a systematic review on genetic mechanisms. Prenatal diagnosis, 35(6), 517–528. https://doi.org/10.1002/pd.4586
Matyášová, M., Dobšáková, Z., Hiemerová, M., Kadlecová, J., Nikulenkov Grochová, D., Popelínská, E., Svobodová, E., & Vlašín, P. (2019). Prenatal diagnosis of Noonan syndrome in fetuses with increased nuchal translucency and a normal karyotype. Prenatální diagnostika syndromu Noonanové u plodů se zvýšeným šíjovým projasněním a normálním karyotypem. Ceska gynekologie, 84(3), 195–200.
Sinajon, P., Chitayat, D., Roifman, M., Wasim, S., Carmona, S., Ryan, G., Noor, A., Kolomietz, E., & Chong, K. (2020). Microarray and RASopathy-disorder testing in fetuses with increased nuchal translucency. Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology, 55(3), 383–390. https://doi.org/10.1002/uog.20352
Alamillo, C. M., Fiddler, M., & Pergament, E. (2012). Increased nuchal translucency in the presence of normal chromosomes. Current Opinion in Obstetrics & Gynecology, 24(2), 102-108. doi:10.1097/gco.0b013e3283505b25
Bilardo, C., Timmerman, E., Pajkrt, E., & Van Maarle, M. (2010). Increased nuchal translucency in euploid fetuses-what should we be telling the parents? Prenatal Diagnosis, 30(2), 93-102. doi:10.1002/pd.2396
