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.

Gender differences of brain metabolic networks: a 18F-FDG PET study / 中华核医学与分子影像杂志

Objective To investigate the gender differences of glucose metabolic network in brains of healthy adults at resting state by 18F-FDG PET.Methods A total of 204 dextromanual,healthy individuals (104 males,average age:(53.45±11.51) years;100 females,average age:(54.11±12.09) years) were enrolled from June 2011 to June 2016 to construct brain metabolic networks.The nodal and global parameters,including clustering coefficient (Cp),characteristic path length (Lp) and betweenness centrality (Cb),were analyzed by graph theory.Permutation test with 1 000 repetitions was used.Results The brain metabolic networks derived from 18F-FDG PET data were with small-world properties in both male group and female group.Compared with Cb in females,Cb in males was significantly reduced in left postcentral gyrus,right angular gyrus and left temporal pole/middle temporal gyrus (permutation test,all P0.05).Conclusions There are gender-related differences of topological structure in whole-brain metabolic networks.Gender should be considered as a covariate while designing experiments,accounting for cerebral metabolic data from normal control and experimental patients as well as making clinical decisions.

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>

Reader association participation-based crowd sourcing of virtual reference service in medical college and university libraries / 中华医学图书情报杂志

As a brand new service mode on Internet,crowd sourcing can solve the problems that need high cost and professionals by drawing on the wisdom of tens of thousands of Internet users. Medical college and university libraries should thus strengthen their virtual reference service teams and further improve their virtual reference service level by introducing the crowd sourcing concept,depending on the support of reader association and drawing on the wisdom of readers.

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>