Mosaic Trisomy 9 in a Male Fetus with Severe Facial Abnormality and Genital Hypoplasia

Fetal trisomy 9 is a rare chromosomal abnormality, which was difficult to diagnose in the prenatal period. Here is reported a case of mosaic trisomy 9 fetus, prenatally detected by ultrasound examinations in the second trimester and confirmed by karyotyping from amniocentesis and cordocentesis. The fetus presented multiple malformations, especially facial deformity, polycystic kidney disease and genital hypoplasia, which were rare in previous literature. Address for correspondence: Dr. Zhihong Yang. Department of Obstetrics and Gynecology, The Second People’s Hospital of Yuhang District, No. 80 Anle Road, Yuhang Town, Yuhang Distract, Hangzhou, Zhejiang 311121, China Telephone: +86-18969017827. E-mail: [email protected] INTRODUCTION Trisomy 9 is one of the relatively uncommon chromosomal disorders, in which the entire 9 chromosome appears three times rather than twice normally in cells of the body. It may be present in one of the three ways: nonmosaic complete trisomy 9 (an entire extra chromosome 9 is present in all cells), mosaic trisomy 9 (presence of trisomic and disomic cells in a variable proportion), and partial trisomy 9 (trisomy for only a part of chromosome 9). Trisomy 9 and mosaic trisomy 9 syndromes were first described by Feingold and Atkins (1973) and Haslam et al. (1973), respectively. Mosaic trisomy 9 is considered to be a rare chromosomal abnormality with limited survival and manifest multiple anomalies. The features commonly associated with trisomy 9 are well documented, including growth retardation, congenital mental retardation, facial deformity, skeletal abnormalities (Akatuska et al. 1979) and congenital heart disease. Here we described a case of a male fetus with mosaic trisomy 9 confirmed by karyotyping from amniocentesis and cordocentesis with multiple malformations, especially severe facial deformity, polycystic kidney disease and genital hypoplasia.