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Karyotyping of long-term cultured chorionic villus sample may give rise to false negative results due to placental mosaicism. To ensure accurate prenatal diagnosis, discordance between karyotyping of chorionic villi cells, fetal ultrasound and NIPT result should be verified by amniocentesis or cordocentesis and application of multiple cytogenetic and molecular techniques.

Karyotyping of long-term cultured chorionic villus sample may give rise to false negative results due to placental mosaicism. To ensure accurate prenatal diagnosis, discordance between karyotyping of chorionic villi cells, fetal ultrasound and NIPT result should be verified by amniocentesis or cordocentesis and application of multiple cytogenetic and molecular techniques.

To explore genetic etiology and prognosis for fetuses with increased nuchal translucency (NT).

A total of 815 fetuses with increased NT (≥ 3.0 mm) were included. The fetuses were grouped by NT thickness and divided into 3.0-3.4 mm, 3.5-4.4 mm, 4.5-5.4 mm, 5.5- 6.4 mm and ≥ 6.5 mm groups. Based on the presence of additional abnormalities, the samples were divided into increased NT alone group and increased NT and other anomalies group. Chromosomal microarray analysis (CMA) was applied as a first-line test to detect pathogenic copy number variations (CNVs). The outcome of the pregnancies was followed up.

One hundred seventy-eight (21.8%) fetuses were found to harbor pathogenic CNVs, which included 138 (77.5%) with chromosomal aneuploidies, 14 (7.9%) with microdeletion/microduplication syndromes, and 26 (14.6%) harboring non-syndromic pathogenic CNVs. A significant difference was found in the detection rate of pathogenic CNVs between groups with different NT thickness. The detection rate of pathogenic CNVs also significantly differed between groups with regard to other structural abnormalities or the overall adverse pregnancy outcome.

CMA can be used as a first-line test for fetuses with increased NT during early pregnancy, with the overall detection rate of pathogenic CNVs being as high as 21.8%. Our results confirmed that NT thickness is correlated with other structural abnormalities and adverse pregnancy outcome, especially for those with NT ≥ 4.5 mm. At the same time, fetuses with other structural abnormalities are at an increased risk for adverse pregnancy outcome.

CMA can be used as a first-line test for fetuses with increased NT during early pregnancy, with the overall detection rate of pathogenic CNVs being as high as 21.8%. Our results confirmed that NT thickness is correlated with other structural abnormalities and adverse pregnancy outcome, especially for those with NT ≥ 4.5 mm. At the same time, fetuses with other structural abnormalities are at an increased risk for adverse pregnancy outcome.

To explore the genetic basis for a child with concomitant spinal muscular atrophy (SMA) and Citrin protein deficiency.

The child was subjected to whole exome sequencing by using target sequence capture high-throughput sequencing. Candidate variants were verified by Sanger sequencing. The SMN genes of the patient were also analyzed through multiplex ligation-dependent probe amplification (MLPA).

The patient was found to carry homozygous deletion of exons 7 and 8 of the SMN1 gene, for which his parents were both carriers. The patient also carried compound heterozygous variants c.1737G>A and IVS16ins3kbof the SLA25A13 gene, in addition with compound heterozygous variants c.948G>A and c.2693T>C of the POLG gene, for which his parents were carriers, too.

Variants of the SLC25A13 gene probably underlay the deficiency of Citrin protein, which may lead to neonatal intrahepatic cholestasis (NICCD). The patient also had SMA. #link# The compound heterozygous variants c.948G>A and c.2693T>C of the POLG gene are likely to cause mitochondrial DNA deletion syndrome type 4A, though other types of mitochondrial disease cannot be excluded.

C of the POLG gene are likely to cause mitochondrial DNA deletion syndrome type 4A, though other types of mitochondrial disease cannot be excluded.

To explore the genetic basis for a child featuring X-linked intellectual disability.

The 1-year-and-6-month-old child presented with growth retardation, intellectual disability and bilateral alternating squint. With DNA extracted from the child and his parents’ peripheral venous blood samples, whole exome sequencing was carried out to identify potential variants that can explain his condition. Suspected variants were validated by Sanger sequencing. The impact of variants was predicted by bioinformatic tools.

The child was found to harbor a de novo nonsense c.3163C>T (p.Arg1055*) variant of the IQSEC2 gene. The variant, unreported previously, was predicted to be pathogenic based on MutationTaster, PROVEAN and SIFT. Analysis using a HomoloGene system suggested Arg1055 in IQSEC2 residues to be highly conserved evolutionarily, and that replacement of Arg1055 may cause destroy of the PH domain (AA 951-1085) and serious damage to the function of IQSEC2 protein. Analysis with UCSF chimera software suggested that the c.3163C>T (p.Arg1055*) variant can induce serious damages to the secondary structures of IQSEC2 protein, causing loss of its function.

The patient’s condition may be attributed to the de novo nonsense variant c.3163C>T (p.Arg1055*) of the IQSEC2 gene.

T (p.Arg1055*) of the IQSEC2 gene.

To explore the genetic basis for a patient with Leydig cell hypoplasia.

Whole exome sequencing was used to detect genetic variants in the patient. GS-5734 price were verified by PCR and Sanger sequencing of the family members.

The patient was found to carry two novel variants, namely c.265A>T (p.Ile189Leu) and c.422T>C (p.Val141Ala), of the luteinizing hormone receptor gene (LHCGR), where were respectively inherited from her father and mother. Upon prenatal diagnosis, the fetus was found to be a heterozygous carrier of the c.265A>T (p.Ile189Leu) variant.

The compound heterozygous variants of c.265A>T (p.Ile189Leu) and c.422T>C (p.Val141Ala) of the LHCGR gene probably underlie the Leydig cell hypoplasia in the patient.

C (p.Val141Ala) of the LHCGR gene probably underlie the Leydig cell hypoplasia in the patient.