YI-YUN TAICHIH-LING CHENCHEN-TU WUCHIEN-NAN LEESHIN-YU LIN2024-11-072024-11-072024-11https://scholars.lib.ntu.edu.tw/handle/123456789/722866Objective: Kleefstra Syndrome (KS) is a rare genetic disorder caused by a deletion at 9q34.3. Studies showed that various heart defects are observed in 41–43% of patients and abnormal features on brain imaging in 58–63%. To date, the prenatal phenotype in KS has yet to be defined. Case report: We present the first prenatal diagnosis and chromosomal microarray analysis (CMA) of a case of 9q34.3 microdeletion in a fetus with increased amniotic fluid, supported by abnormal prenatal ultrasound findings, and confirmed via autopsy. CMA revealed a 2.1 Mb 9q34.3 microdeletion encompassing an OMIM gene of EHMT1, which is consistent with the diagnosis of Kleefstra syndrome and 9q subtelomeric deletion syndrome. Conclusion: When a fetus with normal karyotype presents with polyhydramnios or abnormalities noted during second-trimester prenatal ultrasound screening, CMA analysis can be considered as the next step to rule out or confirm the diagnosis of chromosomal or other genetic aberrations.enKleefstra syndromePolyhydramniosPrenatal diagnosis[SDGs]SDG3journal article10.1016/j.tjog.2024.06.01339482011