Analysis of COL1A1 and COL1A2 gene variants in two fetuses with osteogenesis imperfecta / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis of two fetuses with an osteogenesis imperfecta (OI) phenotype.@*METHODS@#Two fetuses diagnosed at the Affiliated Hospital of Weifang Medical College respectively on June 11, 2021 and October 16, 2021 were selected as the study subjects. Clinical data of the fetuses were collected. Amniotic fluid samples of the fetuses and peripheral blood samples of their pedigree members were collected for the extraction of genomic DNA. Whole exome sequencing (WES) and Sanger sequencing were carried out to identify the candidate variants. Minigene splicing reporter analysis was used to validate the variant which may affect the pre-mRNA splicing.@*RESULTS@#For fetus 1, ultrasonography at 17+6 weeks of gestation had revealed shortening of bilateral humerus and femurs by more than two weeks, in addition with multiple fractures and angular deformities of long bones. WES revealed that fetus 1 had harbored a heterozygous c.3949_3950insGGCATGT (p.N1317Rfs*114) variant in exon 49 of the COL1A1 gene (NM_000088.4). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), it was classified as a pathogenic variant (PVS1+PS2+PM2_Supporting) for disrupting the downstream open reading frame resulting in premature translational termination, being de novo in origin, and lacking records in the population and disease databases.For fetus 2, ultrasonography at 23 weeks of gestation also revealed shortening of bilateral humerus and femurs by one and four weeks, respectively, in addition with bending of bilateral femurs, tibias and fibulas. Fetus 2 had harbored a heterozygous c.1557+3A>G variant in intron 26 of the COL1A2 gene (NM_000089.4). Minigene experiment showed that it has induced skipping of exon 26 from the COL1A2 mRNA transcript, resulting in an in-frame deletion (c.1504_1557del) of the COL1A2 mRNA transcript. The variant was inherited from its father and had been previously reported in a family with OI type 4. It was therefore classified as a pathogenic variant (PS3+PM1+PM2_Supporting+PP3+PP5).@*CONCLUSION@#The c.3949_3950insGGCATGT (p.N1317Rfs*114) variant in the COL1A1 gene and c.1557+3A>G variant in the COL1A2 gene probably underlay the disease in the two fetuses. Above findings not only have enriched the mutational spectrum of OI, but also shed light on the correlation between its genotype and phenotype and provided a basis for genetic counseling and prenatal diagnosis for the affected pedigrees.

Early warning of low maternal unconjugated estriol level by prenatal screening for fetus with X-linked ichthyosis / 中华妇产科杂志

Objective:To analyze the characteristic of prenatal serological screening in fetus with X-linked ichthyosis (XLI), and to explore the relationship between unconjugated estriol (uE 3) levels and XLI. Methods:A total of 56 fetuses with Xp22.31 microdeletion indicated by prenatal diagnosis and 70 fetuses diagnosed with trisomy 21 and 26 fetuses with trisomy 18 in Henan Provincial People's Hospital and Affiliated Hospital of Weifang Medical College from September 2016 to June 2021 were collected. The multiples of median (MoM) values of uE 3, alpha-fetoprotein (AFP), and human chorionic gonadotropin (hCG) during the second trimester of pregnancy were retrospectively analyzed. Prenatal diagnosis was made by amniotic fluid karyotype analysis and genome copy number variant analysis, parent genetic verification and pathogenicity analysis were performed, and maternal and infant outcomes were followed up. Results:Of 56 pregnant women with fetal Xp22.31 microdeletion, 43 underwent serological screening during the second trimester of pregnancy, of which 42 were abnormal (39 male fetuses and 3 female fetuses). The median uE 3 MoM value of 39 male fetuses [0.06 (0.00-0.21)] was lower than the normal value and significantly lower than that of fetuses with trisomy 21 [0.71 (0.26-1.27)] and fetuses with trisomy 18 [0.36 (0.15-0.84)], the difference was statistically significant ( Z=99.96, P<0.001). While the MoM values of AFP and hCG were all within the normal range. Among the 56 fetuses carrying Xp22.31 microdeletion, 45 were male fetuses and 11 were female fetuses, and the deletion fragments all involved STS gene. Eighty-nine percent (50/56) were inherited from mother (49 cases) or father (1 case), and 11% (6/56) were de novo mutations. Follow-up showed 48 live births (38 males and 10 females) and 8 chose to terminate pregnancy (7 males and 1 female). Among the 38 male newborns, 37 presented with scaly skin changes from 1 to 3 months of age, and one had no clinical manifestations until 4 months after birth. Ten female newborns had no obvious clinical manifestations. Conclusions:The decrease levels of uE 3 MoM on maternal serological screening is closely related to the higher risk of XLI in male fetuses. For pregnant women with low uE 3 in serological screening or with family history of ichthyosis, in addition to chromosomal karyotype analysis, joint detection of genomic copy number variant analysis should be recommended.

Detection of NPM1 gene mutation in acute myeloid leukemia / 中华检验医学杂志

Objective To analyze the frequency of NPM1 mutation in de novo acute myeloid leukemia (AML) patients and the relationship between NPM1 mutation and chromosome alterations,as well as FAB subgroups,and to analyze the mutation type.MethodsA total of 99 de novo AML patients from 2004 to 2010 in China-Japan Friendship Hospital were studied.Genomic DNA was amplified by polymerase chain reaction (PCR),denaturing polyacrylamide gel electrophoresis (PAGE) and capillary electrophoresis were used to detect the mutation of NPM1 gene in 99 AML patients,and karyotyping was performed in 72 AML patients by G banding techniques.DNA sequences analysis of NPM1 mutation was performed on 10 patients.Chi-square test was used to compare the frequencies of NPM1 mutation among the different subgroups,and McNemar's test was used to compare the different rates between denaturing PAGE and capillary electrophoresis.ResultsThe frequencies of NPM1 mutations were detected in 15％ (15/99) of AML patients with capillary electrophoresis and 11％ (11/99 ) with denaturing PAGE(x2 =2.25,P ＞0.05 ).The NPM1 was at different rates in M2(27％,8/30),M5(32％,6/19),M6( 13％,1/8),respectively (x2 =1.06,P ＞ 0.05 ),and not detected in the other subgroups.NPM1 mutation in patients with normal karyotype(26％ ) was more prevalent than patients with abnormal karyotype (4％) (x2 =5.61,P ＜ 0.05)All of the 10 patients were of A type ( c.860_863dupTCTG).The C-terminal portion of the NPM protein by replacing the last seven amino acids(WQWRKSL) with 11 residues (CLAVEEVSLRK).Two intronic deletions were novel,one case was IVS10-18_-15delCTTT,the other was IVS10-17_-15delTTT.Conclusions NPM1 mutations represents a common genetic abnormality in AML patients,and NPM1 mutation in patients with normal karyotype is higher than patients with abnormal karyotype.Two new intronic deletion mutations are identified.