Severe Extremity Anomaly and Neurodevelopmental Retardation in an Infant with TAR Syndrome and Differential Diagnosis in Radial Defects

Thrombocytopenia-absent radius (TAR) syndrome is a rare congenital syndrome in which thrombocytopenia and the absence of radius can be accompanied by various organ anomalies. Bilateral phocomelia is the most severe form in this clinic. Thumbs are always present. The deletion of the RNA-binding motif protein 8A (RBM8A) gene on chromosome 1q21.1 in Array Comparative Genomic Hybridization confirms the diagnosis of TAR syndrome. Thrombocytopenia, which can cause complications, tends to resolve in the first year of life. Although there are delays in motor development, mental retardation is not one of the common clinical findings of this syndrome. In the differential diagnosis of severe radial defects, TAR syndrome, Holt-Oram syndrome, Roberts syndrome, Fanconi anemia, and VACTERL association are included. The presence of key findings of each syndrome is important in the differential diagnosis. Here, we aimed to evaluate the approach to the differential diagnosis of severe radial anomalies in a patient with TAR syndrome and neuromotor retardation. Keywords: Phocomelia, TAR syndrome, RBM8A, 1q21.1