Genetic study of a fetus with a de novo Xp22.33;Yp11.2 translocation / 中华医学遗传学杂志

OBJECTIVE@#To delineate cytogenetic and molecular abnormalities of a fetus carrying a de novo 46,X,der(X),t(X;Y)(p22.3;p11.2).@*METHODS@#G-banded karyotyping and next-generation sequencing (NGS) were used to analyze the fetus, his father and sister. Single nucleotide polymorphism-based arrays (SNP-array), multiple PCR and fluorescence in situ hybridization (FISH) were utilized to verify the result.@*RESULTS@#G-banded karyotyping at 320 bands showed that the fetus had a normal karyotype, while NGS has identified a 3.58 Mb microdeletion at Xp22.33 and a Y chromosomal segment of about 10 Mb at Yp11.32p11.2. With the sequencing results, high-resolution karyotyping at 550-750 bands level has determined the fetus to be 46,X,der(X)t(X;Y)(p22.3;p11.2). The result was confirmed by PCR amplification of the SRY gene, FISH and SNP-array assays. The karyotypes of his father and sister were both normal. His sister also showed no amplification of the SRY gene, and her NGS results were normal too, suggesting that the karyotype of the fetus was de novo.@*CONCLUSION@#Combined karyotyping, NGS, SNP-array, PCR and FISH assay can facilitate diagnosis of XX disorder of sex development.

Laboratory investigation of reactive plasmacytosis in patients with severe fever with throbocytopenia syndrome / 中华传染病杂志

Objective To investigate the immunological characteristics and clinical significance of reactive plasmacytosis in patients with severe fever with throbocytopenia syndrome (SFTS).Methods Bunyavirus-infected patients who were diagnosed with SFTS were collected from March 2015 to October 2015 in Taizhou Hospital.Morphology analysis of bone marrow and peripheral blood (PB) smear, as well as flow cytometry analysis of plasma cell immune phenotype from peripheral blood were conducted.Serum immunoglobulin levels and helper T hymphocytes (Th)1/Th2 cytokine expressions were detected.Mann-Whitney U test was used.Results PB plasma cells from all of the SFTS patients increased in varying degrees, and the phenotype of the plasma cells was CD19+CD38++CD45+CD138+, which indicated normal mature plasma cells.The ratio of PB plasma cells was >0.030 in 10/16 patients, and >0.300 in 2/16 patients.The ratios of PB plasma cells in the patients with severe and critical groups were significantly higher than that in the mild group (0.052 vs 0.016, P0.05).The serum IgG, IgA and IgM levels did not increase in acute stage, with the median of 11.6 g/L, 2.56 g/L and 1.60 g/L (reference value 0.46 to 3.04 g/L), respectively.Conclusion The patients with SFTS show excessive humoral and cellular immunity, and the severity of disease is positively correlated with the ratio of peripheral plasma cells and the levels of cytokines IL-6 and IL-10.

Cytogenetic and molecular genetic analysis of small supernumerary marker chromosomes in fetal amniotic fluid / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the origin and mechanism of small supernumerary marker chromosomes (sSMC) in order to facilitate genetic counseling.</p><p><b>METHODS</b>Chromosome karyotypes of two fetuses and their immediate family members were analyzed by conventional G banding. High-throughput whole genome sequencing was used to determine the origin of sSMCs.</p><p><b>RESULTS</b>Fetus 1 was shown to have a karyotype of 47,XY,+mar but with normal FISH and B ultrasound findings. Its father also had a 47,XY,+mar karyotype with normal FISH results and clinical phenotype. High-throughput genome sequencing revealed that fetus 1 and its father were both 46,XY,dup(21)(q11.2;q21.1) with a 6.2 Mb duplication of the long arm of chromosome 21. The fetus was born with normal phenotype and developed well. Its grandmother also had a karyotype of 46,XX,t(15;21)(q13;p13) with normal FISH result and clinical phenotype. The karyotypes of its mother and grandfather were both normal. Analysis of fetus 2 showed a 47,XY,+mar karyotype with normal FISH results. High-throughput genome sequencing suggested a molecular karyotype of 46,XX. The fetus was born with normal phenotype and developed well. The karyotypes of its parents were both normal.</p><p><b>CONCLUSION</b>Considering their variable origins, identification of sSMC should combine conventional G banding analyses with high-throughput whole genome sequencing for precise delineation of the chromosomes.</p>

Genetic analysis and counseling for two fetal cases with large de novo Yq deletions / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the deletion region for two fetal cases with large Yq deletions in order to provide genetic counseling and prenatal diagnosis.</p><p><b>METHODS</b>For both cases, amniotic fluid samples were cultured and analyzed with G banding and fluorescence in situ hybridization (FISH). Multiplex polymerase chain reaction was also carried out to amplify 15 sequence tagged sites (STS) of azoospermia factor (AZF) on the Y chromosome.</p><p><b>RESULTS</b>For both samples, the karyotypes were determined as 46,X,del(Y)(pter→q11:). No heterochromatin was found in C band. The karyotypes of their fathers were 46,XY, and heterochromatin was found in C band. STS analyses suggested that only sY82, sY84 and sY86 in AZFa were amplifiable while the other 12 STS were negative in amniotic fluid for the first case, which indicated deletions of AZFb, AZFd and AZFc. No AZF deletion was found in its father. For the second case, all 15 STS were amplifiable in the amniotic fluid, suggesting no AZF deletion. No AZF deletion was found in its father too.</p><p><b>CONCLUSION</b>Conventional karyotyping combined with FISH and molecular genetics techniques can enable characterization of AZF microdeletions and facilitate genetic counseling and prenatal diagnosis.</p>

Analysis of two false positive cases from noninvasive prenatal testing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To track and analyze two false positive cases from non-invasive prenatal testing for potential fetal aneuploidy.</p><p><b>METHODS</b>The two cases, respectively reported to have XO (+++) and T18 (1/20) XO(+), were analyzed with conventional karyotyping, fluorescence in situ hybridization (FISH) and massively parallel genomic sequencing (MPS).</p><p><b>RESULTS</b>The first fetus, who was suspected for XO(+++), was verified to have super female syndrome (47,XXX/46,XX) due to confined placental mosaicism by karyotyping of amniotic fluid cells, FISH analysis of placenta and massively parallel sequencing (MPS) of fetal tissue. The second fetus, suspected to have trisomy 18 (1/20) XO(+), was verified to have Turner syndrome by karyotyping, FISH and MPS analyses of umbilical cord blood cells. And the karyotype was 45,X[48]/46, X, der(X) del(X) (p11.21) del(X) (q13.3)[62].</p><p><b>CONCLUSION</b>Non-invasive prenatal testing carries a risk for false positive diagnosis of fetal sex chromosome and trisomy 18. Combined cytogenetic and molecular techniques are required to ensure an accurate diagnosis.</p>