title: A case report of prenatally diagnosed tetrasomy 18p.
abstract: Tetrasomy 18p, one of the most commonly observed isochromosomes, consists of two copies of the p arms on chromosome 18[i(18p)]. It is known as a de novo occurrence of non-disjunction or centromeric mis-division during meiosis II in the vast majority of cases. It has a prevalence of 1/140,000-180,000 live births and affects both genders equally. A 28-year-old woman was referred at 33+2 weeks gestation to rule out fetal congenital heart disease. Her prenatal ultrasonography showed intrauterine growth retardation, cardiomegaly, and imperforate anus. Doppler ultrasonographic finding showed fetal anemia. Tetrasomy 18p was confirmed by conventional karyotyping and fluorescence in situ hybridization. Because of its very low prevalence rate, only several cases of tetrasomy 18p has been reported worldwide and it has not yet been reported in Korea before. Therefore, we report a case of prenatally diagnosed tetrasomy 18p.
authors: Department of Obstetrics and Gynecology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
authors: Phill-Seung
authors: PS
authors: Jung
authors: Hye-Sung
authors: HS
authors: Won
authors: In-Ji
authors: IJ
authors: Cho
authors: Min-Kyung
authors: MK
authors: Hyun
authors: Jae-Yoon
authors: JY
authors: Shim
authors: Pil-Ryang
authors: PR
authors: Lee
authors: Ahm
authors: A
authors: Kim
keywords: Isochromosome 18p; Prenatal diagnosis; Tetrasomy 18p