Genetic Study and Prenatal Diagnosis of a Family with Thrombocytopenia-Absent Radius (TAR) Syndrome

  Objective  To analyze the potential genetic cause of thrombocytopenia-absent radius (TAR) syndrome in a family and provide prenatal diagnosis for them.

  Methods  Genetic mutation analysis of the sporadic family with TAR syndrome was performed with chromosome microarray analysis (CMA), quantitative polymerase chain reaction (qPCR) and Sanger sequencing. DNA samples were collected from 4 members of the family, including the proband, her parents and her sister. CMA, qPCR and Sanger sequencing were performed to determine the pathogenic mutation and prenatal diagnosis of the fetus was made accordingly.

  Results  The proband had a 378 kb genomic heterozygous deletion in 1q21.1, which contained RBM8A and other genes. c.-21G>A mutation was also found in the RBM8A of the proband. The above-mentioned microdeletion and mutation were inherited from the mother and father, respectively. Prenatal CMA suggested that the fetus carried a 378 kb microdeletion in 1q21.1, and DNA testing did not find c.-21G>A mutation.

  Conclusion  The heterozygous deletion in 1q21.1 and RBM8A: c.-21G>A is considered to be the genetic etiology of TAR syndrome in the family. The study provides information for subsequent family genetic counseling and prenatal diagnosis.