EP18.46: Kabuki‐Syndrome in a fetus with thickened nuchal translucency and congenital corrected transposition of the great arteries

Elevated Nuchal Translucency is a known unspecific but valid sign for abnormal genetic as well as morphological finding in the embryo/fetus. We report on a routine first trimester scan which showed a nuchal translucency of 2.7mm in 12+2 weeks of pregnancy. A placental biopsy at week 14+2 showed a normal karyotype - array was not recommended by the patient. A close follow up including fetal echocardiography at 18+2 weeks of pregnancy was planned - it showed normal growth with a singular umbilical artery and fetal echography revealed a congenital corrected transposition of the great arteries (ccTGA). After counselling, the genetic analysis was expanded to whole exome analysis. A further sonography at 23+0 weeks confirmed the finding of ccTGA and demonstrated abnormal face and ears in 3D-volumetry. WES results showed a pathologic variation class 4 in the KMT2D-Gene (c.4467_4468del, p.(Cys1489Ter) corresponding to Kabuki-Syndrome Type 1. Kabuki-Syndrome is a rare disorder with multiple congenital anomalies and neurodevelopmental disorder. It is characterised by five major features: intellectual disability, visceral malformations (frequently congenital heart defects), persistence of fetal fingertip pads, postnatal short stature, skeletal anomalies and specific facial features (arched and broad eyebrows, long palpebral fissures, eversion of the lower eyelid, large prominent, cupped ears). Various additional features are frequently observed. Our patient itself was working as an intensive care nurse und opted for termination of pregnancy after intensive counselling. The postnatal evaluation confirmed the pathologic morphology. First trimester sonography is the earliest tool to detect fetuses at risk for morphologic and genetic pathology and is the key to further diagnostic. Close follow up after initial “normal karyotype” is mandatory to identify candidates for expansion of prenatal genetic diagnostics.