OBJECTIVE: To assess the value of chromosomal microarray analysis (CMA) for the detection of low-level mosaicisms in amniotic fluid samples, and to retrospectively analyze the rare cases of mosaicisms. METHODS: Chromosomal karyotype of the fetus was determined by G-banding analysis of cultured amniotic fluid cells. CMA was used to detect copy number variation of fetal chromosomes, and fluorescence in situ hybridization (FISH) was used to determine the proportion of fetal chromosomal mosaicisms in uncultured amniotic fluid cells. RESULTS: Among 825 prenatal samples, 4 cases of true fetal mosaicisms were detected, which yielded an incidence of 0.48%. Two cases were sex chromosomal mosaicisms, and two were autosomal mosaicisms, which involved chromosomes 8 and 9, respectively. All cases were verified by G-banding analysis of cultured amniotic fluid cells, CMA, and/or FISH. CONCLUSION CMA has a great value for detecting low-level mosaicisms in amniotic fluid samples, though the positive results need to be verified by other techniques and should be interpreted with caution. The review of rare cases can provide a basis for prenatal genetic counseling.
Humans ; Female ; Amniotic Fluid/metabolism* ; Pregnancy ; Mosaicism/embryology* ; Prenatal Diagnosis/methods* ; Adult ; In Situ Hybridization, Fluorescence ; Microarray Analysis/methods* ; Karyotyping ; Retrospective Studies ; Male

OBJECTIVETo study the pattern of CGG repeat instability within germline cells derived from two male fetuses affected with Fragile X syndrome (FXS).

METHODSThe length and methylation status of CGG repeats within the testes of a fetus carrying a full FXS mutation and another fetus carrying mosaicism FXS mutation were analyzed with Southern blotting and AmplideX FMR1 PCR. Immunohistochemistry was also applied for the measurement of FMR1 protein (FMRP) expression within the testes.

RESULTSFor the fetus carrying the full mutation, Southern blotting analysis of the PCR product has detected an expected band representing the full mutation in its brain and a premutation band of > 160 CGG repeats in its testis. Whereas the pattern of premutation/full mutation in mosaic testis was similar to that in peripheral blood and no sign of contracted fragment was found other than a band of about 160 CGG repeats. Immunohistochemistry assay with a FMRP-specific antibody demonstrated a number of FMRP-positive germ cells, which suggested a contraction from full mutation to premutation alleles.

CONCLUSIONThis study has clarified the instability pattern of CGG repeat and expression of FMRP protein within the testes of fetuses affected with FXS, confirming that the CGG repeat can contract progressively within the germline. The FMRP expression in the testis is consistent with spermatogonium proliferation, and thus the contraction from full mutation to unmethylated premutations may occur for the requirement of FMRP expression during spermatogenesis. The better understanding of FMRP function during germ cell proliferation may elucidate the mechanism underlying the contraction of full FXS mutation in male germline.

Abortion, Eugenic ; Blotting, Southern ; Brain ; embryology ; metabolism ; DNA Methylation ; Fatal Outcome ; Fetus ; cytology ; metabolism ; Fragile X Mental Retardation Protein ; genetics ; metabolism ; Fragile X Syndrome ; diagnosis ; genetics ; Humans ; Immunohistochemistry ; Male ; Mosaicism ; Mutation ; Polymerase Chain Reaction ; Spermatozoa ; metabolism ; Testis ; cytology ; embryology ; metabolism ; Trinucleotide Repeat Expansion ; genetics

OBJECTIVETo provide genetic analysis for a family affected with Duchenne muscular dystrophy (DMD) with a recurrent de novo mutation.

METHODSMultiplex ligation dependent probe amplification (MLPA) was used to detect potential deletion and duplication of the DMD gene, and the DNA products were sequenced on a Genetic Analyzer 3130 sequencer. Haplotype analysis was performed using four short tandem repeat polymorphism loci (44C/A, 45C/A, 49C/A and 63C/A) of the DMD gene for the family.

RESULTSA same deletional mutation (Del 48-50) of the DMD gene was detected in the proband and fetus, but not in their mother. The proband and fetus have inherited the same haplotype of the DMD gene from their mother. The fetus was predicted to be affected by the disease.

CONCLUSIONAbove findings suggested that the mother was very likely to have a germline mosaicism for the DMD gene mutation. For the de novo DMD mutation, although genetic analysis of peripheral blood DNA has indicated that the proband's mother was not a carrier, germline mosaicism could still not be ruled out, and prenatal gene diagnosis should be provided for subsequent pregnancies.

Adult ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Child ; China ; Dystrophin ; genetics ; Female ; Fetal Diseases ; diagnosis ; genetics ; Humans ; Infant ; Male ; Molecular Sequence Data ; Mosaicism ; Muscular Dystrophy, Duchenne ; embryology ; genetics ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Sequence Deletion

OBJECTIVETo use different technologies to distinguish true and pseudo mosaicisms among cultured amniocytes in order to attain more accurate diagnosis.

METHODSWith informed consent, 20 mL of amniotic fluid was obtained from pregnant women at between 18 to 24 gestational week. Each amniotic fluid sample was processed as two separate lines for the culturing, observation, harvesting and analysis. All procedures were conducted conforming to the Technology Standards of Cytogenetic Prenatal Diagnosis of Fetal Chromosome Abnormalities issued by the Ministry of Health in 2010. Umbilical cord blood, fluorescence in situ hybridization (FISH), single nucleotide polymorphism array (SNP-array) and flow cytometer were applied when necessary.

RESULTSAmong 3910 cases, 128(3.3%) were detected as mosaicisms. Further analysis with the above technologies has verified 6 cases as true mosaicisms and the remaining 120 as pseudomosaicisms. For one case detected by karyotype analysis as 47, XXY/46, XY, the ratio of different cell lines was confirmed by FISH as 1:2. Another case, detected by karyotype analysis as 47, XX,+mar/46, XX (1:1), was verified by SNP-array as 18p duplication. A suspected polyploidy mosaicism was rejected by flow cytometry and cord blood karyotyping.

CONCLUSIONTwo separate cell cultures are important for distinguishing true and pseudo mosaicisms. Combined FISH, SNP-array and flow cytometry can attain more reliable and accurate diagnosis for mosaicisms.

Adult ; Amniotic Fluid ; cytology ; metabolism ; Cells, Cultured ; Chromosome Disorders ; diagnosis ; embryology ; genetics ; Chromosomes, Human, Pair 18 ; genetics ; Cytogenetic Analysis ; methods ; Female ; Fetal Diseases ; diagnosis ; genetics ; Genetic Testing ; methods ; Gestational Age ; Humans ; In Situ Hybridization, Fluorescence ; Karyotype ; Karyotyping ; Microarray Analysis ; methods ; Mosaicism ; Polymorphism, Single Nucleotide ; Pregnancy ; Prenatal Diagnosis ; methods ; Trisomy ; diagnosis ; genetics ; Trisomy 18 Syndrome

OBJECTIVETo detect mosaic trisomy 9 missed by conventional cytogenetics.

METHODSPeripheral blood genomic DNA from a girl with mental retardation was analyzed using Affymetrix CytoScan (TM) HD array. Fluorescence in situ hybridization (FISH) was also performed on samples from two patients.

RESULTSThe SNP-array analysis has revealed multiple duplications along chromosome 9. FISH analysis showed that, for the peripheral blood sample from one patient, 40 of 100 interphase cells and 15 of 100 metaphase cells carried trisomy 9. For the cord blood sample from another patient, 35 of 100 interphase cells and 10 of 100 cultured cells carried trisomy 9.

CONCLUSIONSNP-array is useful for detecting low-level mosaicism which may be missed by conventional cytogenetics. Combined with karyotype and microarray analyses, FISH is a focused and targeted approach for diagnosing mosaic trisomy. They may provide a useful tool for differentiating pseudomosaicisms from true mosaicisms.

Adult ; Chromosomes, Human, Pair 9 ; genetics ; Female ; Humans ; In Situ Hybridization, Fluorescence ; Infant ; Male ; Mosaicism ; embryology ; Oligonucleotide Array Sequence Analysis ; instrumentation ; methods ; Polymorphism, Single Nucleotide ; Pregnancy ; Prenatal Diagnosis ; Trisomy ; diagnosis ; genetics ; Uniparental Disomy ; cytology ; diagnosis ; genetics

OBJECTIVETo analyze sex chromosome mosaicisms in early cleavage-stage human embryos and blastocysts with poor embryo quality score based on the numbers of pronucleus(PN) zygotes using X,Y dual color fluorescence in situ hybridization (FISH), and to discuss the possible mechanisms.

METHODSFresh or frozen-thawed early cleavage-stage human embryos and blastocysts with poor embryo quality score not suitable for embryo transfer were studied with dual color FISH.

RESULTSDouble signal rate of 2PN among early cleavage-stage embryos was 66.67%, which was significantly higher than 1PN and 3PN embryos. Single signal rate of 1PN early cleavage-stage embryos was 90.41%, which was significantly higher than 2PN and 3PN ones. Three signal rate of 3PN early cleavage-stage embryos was 28.00%, which was significantly higher than 1PN and 2PN ones. Double signal rate of 3PN ones was 46.00%, which was significantly higher than 1PN ones. The polyploid rate of frozen-thawed early cleavage-stage embryos was 23.53%, which was slightly higher than that of fresh embryos, but with no statistical significance. The mosaicism rate of 24 blastocysts was 100.00% and the double signal dominant (≥ 50%) rate was 62.50%, which was significantly higher than the rate of early cleavage-stage embryos.

CONCLUSIONUsing 2PN as the criterion for embryo quality score cannot guarantee the selection of normal fertilized embryo for transplantation. Frozen-thawed embryos may harbor more polyploid cells. To avoid the selection of embryos with abnormal chromosomes, combinations of pre-implantation genetic diagnosis (PGD) and prenatal diagnosis are necessary. Meanwhile, blastocysts with poor quality scores may provide an important source for embryo stem cells.

Blastocyst ; metabolism ; Cleavage Stage, Ovum ; metabolism ; Fertilization in Vitro ; Humans ; In Situ Hybridization, Fluorescence ; Mosaicism ; embryology ; Sex Chromosomes

OBJECTIVETo investigate the mechanism and factors affecting mosaicism in human preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization(FISH).

METHODSTotally 51 normal fertilized embryos, which were not suitable for embryo transfer and cryopreservation, were analyzed on day 3 after fertilization by using two sequential rounds of FISH. Chromosomes 13, 16, 18, 21, 22, X and Y were analyzed.

RESULTSAmong 51 embryos, 16 (31.4%) were mosaic, 12 (23.5%) were chaotic, and the remaining were either normal (27.5%) or non-mosaic abnormal (17.6%). The incidence of mosaic embryos was related to embryo developmental stage, for the incidence of mosaicism increased from 12.5% in embryos

CONCLUSIONMosaicism is common in human preimplantaion embryos, which may be one of the important factors affecting the success rates in IVF-ET. Most of the chromosomal abnormalities can be identified by two sequential rounds of FISH.

Aneuploidy ; Blastocyst ; Chromosomes, Human ; Embryo Transfer ; Female ; Humans ; In Situ Hybridization, Fluorescence ; methods ; Mosaicism ; chemically induced ; embryology ; Preimplantation Diagnosis

Congenital diaphragmatic hernia (CDH) is often associated with major anomalies and chromosomal abnormalities. Chromosomal abnormalities are usually detected in 9.5% to 34% of fetuses with CDH prenatally diagnosed and the defect has also been reported in association with multiple syndromes such as Pallister-Killian syndrome, Fryns syndrome, Di George syndrome and Apert syndrome. Among the chromosomal abnormalities associated with CDH, trisomy 21, 18, and 13 are most common. Association with complex chromosomal aberrations such as mosaicism has also been reported. However, CDH presented in a fetus with Y-autosome translocation is extremely rare. Herein, we reported a case of fetus with 46,XY/46,X,-Y, +der(Y)t(Y;1)(q12;q12) mosaicism who presented with CDH diagnosed by ultrasonography at 19 weeks' gestation.
*Chromosome Aberrations ; Hernia, Diaphragmatic/*congenital/*diagnosis/genetics ; Humans ; Mosaicism/*embryology ; Prenatal Diagnosis/*methods

In order to evaluate the effects of sex chromosomal mosaicism on the accuracy of single-cell gender diagnosis, sex chromosomes of 21 normal fertilized embryos were detected by dual color fluorescent in-situ hybridization (FISH). The results showed that 4 embryos had sex chromosomal mosaicism (19%) and the remaining 17 showed uniformly XX or XY signals in all blastomeres. In conclusion, identification of sex by dual color FISH analysis of a single cell was accurate and efficient, and sex chromosomal mosaicism would not affect preimplantation gender diagnosis.
Blastocyst ; Chromosomes, Human, X ; genetics ; Chromosomes, Human, Y ; genetics ; Embryonic Development ; Female ; Humans ; In Situ Hybridization, Fluorescence ; Mosaicism ; genetics ; Pregnancy ; Preimplantation Diagnosis ; methods ; Sex Chromosome Aberrations ; embryology ; Sex Chromosome Disorders ; diagnosis ; Sex Determination Processes