The failure of non-invasive prenatal testing due to maternal dermatomyositis.

We experienced a case of a pregnant woman who failed to obtain a result from NIPT, due to the high level of total cell-free DNA. A subsequent ultrasound examination discovered that the fetus had severe intrauterine growth restriction, so the woman decided to abort the baby. At the same time, the woman developed slight swelling and tenderness of the proximal interphalangeal and meta-carpophalangeal joints. At first, these symptoms were not noticed, but, when the pregnant woman was admitted to the hospital, her laboratory tests were seriously abnormal, such as serum lactate dehydrogenase (640U/L), creatine phosphor kinase (4525U/L), kinase isoenzyme MB (170U/L), and a hydroxybutyrate dehydrogenase (398U/L). The patient had no other symptoms at this time. Misoprostol and subsequent forceps curettage were used for the induced abortion, a 167-g female fetus was aborted. Fetal skin tissue was taken for chromosomal microarray analysis (CMA) and placenta (biopsied in four places and tested as two composite samples) were taken for postnatal karyotyping to exclude a confined placental mosaicism, chromosomal microarray analysis of the fetal skin tissue revealed that the karyotype was 46, XX, karyotyping of placenta (100 cells) gave results of 46, XX, no abnormalities were detected. Ten days after induction, the patient had developed progressive symmetric muscle weakness in the proximal extremities. Physical examination revealed Gottron's sign and erythema. A manual muscle test showed weakness of the muscles (4/5) of her proximal extremities. Electromyography showed myogenic impairment. After excluding the possibility of neoplasia, the patient was diagnosed with dermatomyositis.

Noninvasive prenatal screening for fetal common sex chromosome aneuploidies from maternal blood.

Objective To explore the feasibility of high-throughput massively parallel genomic DNA sequencing technology for the noninvasive prenatal detection of fetal sex chromosome aneuploidies (SCAs). Methods The study enrolled pregnant women who were prepared to undergo noninvasive prenatal testing (NIPT) in the second trimester. Cell-free fetal DNA (cffDNA) was extracted from the mother's peripheral venous blood and a high-throughput sequencing procedure was undertaken. Patients identified as having pregnancies associated with SCAs were offered prenatal fetal chromosomal karyotyping. Results The study enrolled 10 275 pregnant women who were prepared to undergo NIPT. Of these, 57 pregnant women (0.55%) showed fetal SCA, including 27 with Turner syndrome (45,X), eight with Triple X syndrome (47,XXX), 12 with Klinefelter syndrome (47,XXY) and three with 47,XYY. Thirty-three pregnant women agreed to undergo fetal karyotyping and 18 had results consistent with NIPT, while 15 patients received a normal karyotype result. The overall positive predictive value of NIPT for detecting SCAs was 54.54% (18/33) and for detecting Turner syndrome (45,X) was 29.41% (5/17). Conclusion NIPT can be used to identify fetal SCAs by analysing cffDNA using massively parallel genomic sequencing, although the accuracy needs to be improved particularly for Turner syndrome (45,X).

Overall evaluation of the clinical value of prenatal screening for fetal-free DNA in maternal blood.

OBJECTIVE: To explore the clinical value of prenatal screening for fetal-free DNA in maternal blood. METHODS: A total of 10,275 maternal blood samples were collected from October 2012 to May 2016 at the prenatal diagnosis center of Changzhou Woman and Children Health Hospital. RESULTS: Among 10,275 pregnant women accepted noninvasive prenatal testing (NIPT), 9 cases could not get the results after collected the blood second times. The rate of NIPT failure was 0.09%. Seventy-two cases got the NIPT positive results of trisomy 21/trisomy 18/trisomy 13, and the detection rate, specificity, positive predictive value (PPV), and false positive rate were 98.59%, 99.99%, 97.22%, and 0.02%. The top-3 indications of the study were advanced age women (34.90%), high risk (25.22%), and intermediate risk (19.56%). They all had the satisfactory results of NIPT. Fifty-seven pregnant women had the high risk of fetal sex chromosomal aneuploidies (SCA). After informed consent, 33 cases accepted prenatal diagnosis. Eighteen cases were confirmed as sex chromosome aneuploidies. The PPV was 54.54%. Compared with other SCA, the PPV of Turner syndrome was lower. One case was false negative after followed up. CONCLUSIONS: NIPT showed a broad application prospects for prenatal screening and diagnosis of fetal chromosomal diseases. We should deepen mining and analyzing the clinical data, and explore the use of NIPT more reasonably from the perspective of evidence-based medicine.