EP06.54: Prenatal diagnosis of Andersen‐Tawil syndrome: a case report

We present the case of a secundigesta patient, with no previous relevant history. The patient came for her first pregnancy examination in the 20th week. The ultrasound revealed an anomalous short femur with possible agenesis/hypoplasia of the ipsilateral tibia and fibula with anomalous flexion of the foot. Amniocentesis was performed showing a pathogenic variant on KCNJ2 related to Andersen Tawil Syndrome that could explain its phenotype. Andersen Tawil syndrome is a condition characterised by muscle weakness (periodic paralysis), arrhythmias and physical abnormalities such as short stature, scoliosis, hypertelorism, micrognathia, clinodactyly, brachydactyly, syndactyly and limb deformities. The syndrome shows high intrafamilial phenotypic variability and incomplete penetrance, with Autosomal Dominant inheritance pattern and it is due to heterozygous alterations in the KCNJ2(17q24.3) gene. In the case reported, a genetic study of the variant detected in the parents is crucial for an adequate genetic counselling in a dedicated unit.