[Prenatal diagnosis of fetal urinary abnormalities and microdeletion on chromosome 1q21.1].

OBJECTIVE: To investigate genetic etiology of fetal urinary abnormalities with array-based comparative genomic hycridization(array-CGH). METHODS: Thirty-two fetuses with variable urinary abnormalities but normal karyotyping by conventional cytogenetic technique were selected. DNA from the fetuses and their parents samples were prepared and hybridization with Affymetrix cytogenetic 2.7M arrays by follwing the manufacture's standard protocol. The data were analyzed by special CHAS software packages. RESULTS: By using array-CGH detection, genomic imbalanced copy number variations (CNVs) were identified in night fetuses(28%), four out of night CNVs were inherited from parental samples; two were indicated to be benign variants(6%) in the database; and the other three CNVs (9%) were all de novo adjacent microdeletions and microduplication mapping on to common chromosome 1q21.1 region, within which was genitourinaty system function associated gene PDZK1. CONCLUSION: The incidence of genomic unbalanced variations in fetuses with congenital urinary malformations is approximately 28%, including about 9% pathogenic variations. Copy number variations (CNVs) of chromosome 1q21.1 region are associated with congenital urinary malformations which may be due to haploinsufficiency or overexpression of PDZK1 gene.

[Short tandem repeat polymerase chain reaction used in prenatal diagnoses of the zygosity and common chromosomal trisomies in multiple pregnancies].

OBJECTIVE: To evaluate the value of short tandem repeat polymerase chain reaction (STR-PCR) in identification of zygosity in multiple pregnancy and detection of the common chromosomal trisomies. METHODS: Amniotic fluid or fetal blood samples were collected from 38 fetuses in 17 multiple pregnant women who had indications for prenatal diagnosis or planed to be performed feticide. Of the 17 cases there were 13 sets of twins (26 fetuses) and 4 sets of triplets (12 fetuses). Parental blood samples were collected. STR-PCR technique was employed to determine the zygosity and detect trisomy 21, trisomy 18, trisomy 13, and trisomy sex chromosomes. Amniotic fluid or blood samples were collected from 18 singleton pregnant fetuses as controls for detecting chromosomal trisomies. RESULTS: All 7 cases with gestation by assisted reproductive techniques were multizygotic. In 7 cases associated with one fetal malformation, only one set of twin was dizygotic. There were no above mentioned trisomies found in the multiple pregnancies while 2 trisomy 21, one trisomy 18 and 13 respectively were detected in the singleton pregnant group. Feticide was performed on 4 multizygotic cases in which 3 were triplets and 1 was twin associated with an abnormal fetus. Following-up showed that there was no any bad effect after procedure. CONCLUSION: STR-PCR can be used in identifying the zygosity correctly and quickly while being used in detecting chromosomal trisomies. It facilitates monitoring multiple pregnancy as well as selecting appropriate methods of feticide.