Diagnostic value of targeted sequencing panel for genetic variation in neonates in neonatal intensive care unit / 中华围产医学杂志

Objective:To investigate the clinical value of targeted sequencing panel in the detection of genetic variation in neonates in neonatal intensive care unit (NICU).Methods:All neonates (≤28 d of age) admitted in the NICU (case group) and 200 full-term healthy neonates born with no obvious phenotypic abnormalities of Huzhou Maternity and Child Health Care Hospital were enrolled in this prospective study from November 2022 to January 2023. Based on a list of preventable and treatable rare diseases as well as newly screened diseases in China, a targeted sequencing panel suitable for Chinese newborns was designed to target the pathogenic genes and mutation sites associated with 601 genes and 542 diseases. Dried blood spot specimens were prepared and analyzed by the targeted sequencing panel. Pathogenic sites detected by the panel sequencing were verified using Sanger sequencing. The genetic testing results were analyzed according to the clinical features of the neonates. According to the number of primary clinical diagnosis index (including premature infants, neonatal hyperbilirubinemia, hemorrhagic diseases, neonatal infections, ventricular septal defect/patent ductus arteriosus, and others), these patients were divided into four groups with 1, 2, 3, and ≥4 diagnosis index, respectively. Chi-square test and linear correlation Chi-square test were used for statistical analysis. Results:There were 173 patients in the case group and 30.6% (53/173) of them carried pathogenic variants, including 52 positive for pathogenic genes and one with chromosome copy number variant. The positive rate of pathogenic genes was significantly higher in the case group than in the control group [30.1% (52/173) vs. 15.0% (30/200), χ 2=12.26, P<0.001]. Fourteen pathogenic genes were detected in the case group, including FLG, UGT1A1, G6PD, MYH7, AR, ABCC2, ACADS, CYP21A2, GJB2, MEFV, PAH, PKHD1, SCN4A, and HBA. In the case group, the detection rate of pathogenic variants in jaundiced neonates was higher than that in non-jaundiced neonates [35.2% (44/125) vs. 18.8% (9/48), χ 2=4.42, P=0.036]. However, there were no statistically significant differences in the detection rates of pathogenic variants between male and female infants, infants born to mothers of advanced maternal age or not, infants born to mothers with or without gestational diabetes mellitus, premature and term infants, or infants with or without hemorrhagic disorders, neonatal infections, or ventricular septal defects/patent ductus arteriosus in the case group (all P>0.05). The detection rate of pathogenic variants showed a linear increase in infants with 1, 2, 3, and ≥4 diagnosis index [21.1% (8/38), 25.4% (15/59), 38.2% (13/34), and 40.5% (17/42); linear correlation χ 2=4.84, P=0.028]. In the case group, seven genes with a high detection rate of genetic variation (including positive pathogenic genes and carriers) were UGT1A1 [had the highest detection rate, 24.9% (43/173)], GJB2, FLG, DUOX2, ABCA4, G6PD, and MUT. Seven loci with higher mutation frequency were c.211G>A(p.Gly71Arg), c.1091C>T(p.Pro364Leu), c.-41_-40dupTA, and c.686C>A(p.Pro229Gln) in the UGT1A1 gene, c.109G>A(p.Val37Ile) in the GJB2 gene, and c.12064A>T(p.Lys4022Ter) and c.3321del(p.Gly1109GlufsTer13) in the FLG gene. Conclusion:This panel sequencing can provide effective genetic testing for neonates in NICU, especially in children with complex clinical diagnosis.

Analysis of pathogenic variants of USH2A gene in a child with Usher syndrome type II / 中华医学遗传学杂志

OBJECTIVE@#To detect pathogenic variant in a child featuring Usher syndrome type II.@*METHODS@#Peripheral blood samples of the child and his parents were collected for the analysis of variants of hearing impairment-related genes. The findings were verified in 100 individuals with normal hearing.@*RESULTS@#The child was found to harbor compound heterozygous variants of the USH2A gene, namely c.8224-1G>C in intron 41 and c.5678C>G(p.Ser1893X) in exon 28, which were inherited respectively from his mother and father. Based on the American College of Medical Genetics and Genomics standards and guidelines, both c.8224-1G>C and c.5678C>G(p.Ser1893X) variants of USH2A gene were predicted to be pathogenic(PVS1+PM2+PM3).@*CONCLUSION@#The compound heterozygous variants c.8224-1G>C and c.5678C>G of the USH2A gene probably underlay the disease in this child. Above finding has enriched the spectrum of USH2A gene variants.

Genetic analysis and prenatal diagnosis of a pregnant woman with Sheldon-Hall syndrome / 中华医学遗传学杂志

OBJECTIVE@#To provide genetic testing and prenatal diagnosis for a woman with Sheldon-Hall syndrome.@*METHODS@#The woman was subjected to targeted capture and next-generation sequencing for variant of genes associated with skeletal disorders. And the result was verified in her parents and fetus.@*RESULTS@#The woman was found to harbor a c.188G>A variant of the TNNT3 gene, which was also found in her affected mother and the fetus. Her grandmother and grandmother's brother had similar manifestations, which was in line with an autosomal dominant inheritance. The same variant was not found in her father.@*CONCLUSION@#The c.188G>A variant of the TNNT3 gene probably underlay the distal joint contracture in this pedigree, based on which prenatal diagnosis was attained.