[Genetic analysis and prenatal diagnosis of a fetus with harlequin ichthyosis].

OBJECTIVE: To carry out variant analysis for a fetus suspected with harlequin ichthyosis (HI). METHODS: Whole exome sequencing (WES) was employed to detect potential variant in the fetus. Suspected variant was validated by Sanger sequencing. RESULTS: A homozygous missense variant c.6858delT (p.F2286fs) was detected in the fetus, for which both parents were heterozygous carriers. Pathological analysis confirmed the diagnosis of HI. CONCLUSION: The c.6858delT variant of the ABCA12 gene probably underlies the disease in the fetus.

[Genetic diagnosis and noninvasive prenatal testing of a family with Williams-Beuren syndrome].

OBJECTIVE: To explore the genetic basis of a fetus with ventricular septal defect (VSD) by using modified noninvasive prenatal testing (NIPT) for the detection of microdeletion syndromes. METHODS: Chromosomal karyotypes of the fetus and its parents were analyzed by G-banding technique. Next generation sequencing (NGS) was used to detect genomic copy number variations (CNVs) in cell-free fetal DNA. The results were verified by fluorescence in situ hybridization (FISH). RESULTS: The fetus and its parents all had a normal karyotype at 320-400 band level. NGS revealed a deletion of 1.30 Mb at 7q11.23 in the fetus, with a 93% overlap with that of Williams-Beuren syndrome (WBS). The father also had a deletion of 1.42 Mb at 7q11.23, with a 99% overlap with that of WBS. Modified NIPT also detected the 1.30 Mb deletion at 7q11.23 in the fetus. The result of FISH has confirmed the above results. CONCLUSION: It is necessary to carry out genetic testing on fetuses with VSD. NGS can detect fetal microdeletion syndromes and help to trace their parental origin. The modified NIPT for fetal chromosomal microdeletions/microduplication syndromes is highly accurate.