The discovery of cell-free fetal DNA (cff-DNA) in maternal plasma offered a new way to noninvasive prenatal diagnosis for single gene disorders. In the past decade, many techniques such as real-time PCR, pyrophosphorolysis-activated polymerization, mass spectrum and digital PCR have been developed for noninvasive prenatal diagnosis. In this review, the author discuss the principles, applications, advantages and disadvantages of these techniques.
DNA ; blood ; genetics ; Female ; Fetal Diseases ; diagnosis ; genetics ; Genetic Diseases, Inborn ; diagnosis ; genetics ; Humans ; Maternal-Fetal Exchange ; Pregnancy ; Prenatal Diagnosis ; methods

Preimplantation genetic diagnosis is a very early form of prenatal diagnosis aimed at eliminating embryos carrying serious genetic diseases before implantation. The basic techniques currently used involve embryo biopsy, the polymerase chain reaction and fluorescence in situ hybridization. In the current review, a number of problems arising from the use of these technologies as well as the possible solutions and new developments are discussed.
Cytogenetic Analysis ; Female ; Fetal Diseases ; diagnosis ; genetics ; Humans ; Pregnancy ; Preimplantation Diagnosis ; Primed In Situ Labeling

OBJECTIVETo establish a means for prenatal prediction of spinal muscular atrophy (SMA) through survival motor neuron (SMN) gene deletion analysis and genetic counseling in families with a child affected with SMA.

METHODSGenetic analysis for prenatal prediction of Werdnig-Hoffmann disease was performed in a at risk Chinese family by polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) in SMN gene exons 7 and 8.

RESULTSThe pregnancy was positive for the homozygous deletion of the SMN gene, thus the fetus was diagnosed as being affected and the pregnancy was terminated.

CONCLUSIONThis approach is fast and reliable for DNA-based prenatal diagnosis of Werdnig-Hoffmann disease.

China ; Female ; Fetal Diseases ; diagnosis ; Gene Deletion ; Genetic Counseling ; Humans ; Pregnancy ; Prenatal Diagnosis ; Spinal Muscular Atrophies of Childhood ; diagnosis ; genetics

OBJECTIVETo explore the application of combined techniques for the prenatal diagnosis of a case with 7q11.23 duplication.

METHODSAmniocentesis was performed in the second trimester for a mother with a high risk suggested by serological prenatal screening. G-banded chromosomal analysis was performed on cultured amniocytes and peripheral blood samples from both parents. DNA from amniotic fluid sample was isolated for a BACs-on-Beads (BoBs) assay. To define the range of duplication, copy number variation was determined with single nucleotide polymorphism array (SNP array, Affymetrix CytoScan 750K) and fluorescence in situ hybridization (FISH) analysis.

RESULTSChromosomal analysis suggested that the fetus and both parents all had a normal karyotype, while a duplication of 7q11.23 was detected by the BoBs assay. SNP array revealed a 1.5 Mb duplication in chromosome 7q11.23, which was confirmed by FISH.

CONCLUSIONCombined prenatal BoBs, SNP array and FISH has enabled effective diagnose of a case with 7q11.23 syndrome.

Adult ; Chromosome Banding ; Chromosome Disorders ; diagnosis ; embryology ; genetics ; Chromosomes, Human, Pair 7 ; genetics ; Female ; Fetal Diseases ; diagnosis ; genetics ; Humans ; Male ; Middle Aged ; Pregnancy ; Prenatal Diagnosis ; Trisomy ; genetics

OBJECTIVETo screen for genomic copy number variants (CNVs) in a fetus with one sibling affected with Prader-Willi syndrome using single nucleotide polymorphism (SNP) array.

METHODSThe fetus and its parents were subjected to chromosomal karyotyping and SNP array analysis.

RESULTSA 5p15.33 microdeletions was identified in the fetus and its phenotypically normal mother with a size of 344 kb (113 576 to 457 213). The father was normal for both testing. Analysis of literature and CNVs database indicated the above CNV to be variant of unclear significance. The couple decided to continue with the pregnancy and gave birth to a healthy boy at full-term. No abnormalities were found during the follow-up.

CONCLUSIONThis study may provide further data for the phenotype-genotype correlation of 5p15.33 microdeletion, which differs from Cri du Chat syndrome.

Adult ; Chromosome Deletion ; Chromosomes, Human, Pair 5 ; genetics ; DNA Copy Number Variations ; Female ; Fetal Diseases ; diagnosis ; genetics ; Humans ; Male ; Prader-Willi Syndrome ; diagnosis ; embryology ; genetics ; Pregnancy ; Prenatal Diagnosis

OBJECTIVETo establish a method for the prenatal diagnosis of 22q11 microdeletion syndrome.

METHODSBACs-on-Beads (BoBs) and fluorescence in situ hybridization (FISH) were performed on a fetus for whom amniotic chromosomal culturing has failed and a pair of twin fetuses suspected for 22q11 deletion syndrome.

RESULTS22q11 microdeletion was detected in all 3 fetuses by prenatal BoBs as well as FISH, with only one red signal detected at the DiGeorge/VCFS N25 site and two green signals on the 22q13.3 ARSA site.

CONCLUSIONThe combination of prenatal BoBs and FISH can provide a method for the prenatal diagnosis of 22q11 microdeletion.

Adult ; Chromosome Deletion ; Chromosomes, Human, Pair 22 ; genetics ; DiGeorge Syndrome ; diagnosis ; embryology ; genetics ; Female ; Fetal Diseases ; diagnosis ; genetics ; Humans ; In Situ Hybridization, Fluorescence ; Karyotyping ; Pregnancy ; Prenatal Diagnosis

OBJECTIVETo analyze 81 spontaneous abortion samples with fluorescence in situ hybridization (FISH).

METHODSChromosome 13, 21, 16, 22, 18, X and Y probes were used to detect the samples.

RESULTSFISH was successful in 80 cases (98.77%). Among these, 35 (43.75%) had an abnormal karyotype, which included 19 autosomal aneuploidies, 6 sex chromosome aneuploidies, 9 triploidies and 1 tetraploidy.

CONCLUSIONFISH is a rapid and easy method for detecting chromosomal aneuploidies in spontaneous abortion samples, and has a higher detection rate in early spontaneous abortion samples.

Abortion, Spontaneous ; diagnosis ; genetics ; Adult ; Aneuploidy ; Chromosome Aberrations ; Chromosomes, Mammalian ; genetics ; Female ; Fetal Diseases ; diagnosis ; genetics ; Humans ; In Situ Hybridization, Fluorescence ; Male ; Middle Aged ; Pregnancy ; Prenatal Diagnosis ; Young Adult

OBJECTIVETo conduct prenatal diagnosis on the couples carrying Thailand deletion (--THAI) alpha-thalassemia 1 and at high risk of having fetus with alpha-thalassemia.

METHODSGenotypes of couples and fetuses were analyzed by PCR and DNA sequencing.

RESULTSFour pregnant women were patients with Hb H diseases of --THAI compounding with alpha-thalassemia 2, while their husbands were heterozygote of the Southeast Asian type alpha-thalassemia 1 (--SEA). Another 5 families, either husbands or wives were heterozygote of --THAI or --SEA. The genotypes of their fetuses were as follows: 2 cases with Hb Bart's hydrops fetalis syndrome, 1 Hb H disease, 4 alpha-thalassemia heterozygote and 2 normal. The DNA sequencing approved the PCR results.

CONCLUSIONThe study on prenatal diagnosis of Thailand deletion alpha-thalassemia 1 is of importance to the genetic counseling and prenatal diagnosis of alpha-thalassemia.

Adult ; Base Sequence ; Female ; Fetal Diseases ; blood ; diagnosis ; genetics ; Genotype ; Hemoglobins ; analysis ; Humans ; Male ; Pregnancy ; Prenatal Diagnosis ; Sequence Analysis, DNA ; Sequence Deletion ; genetics ; alpha-Thalassemia ; blood ; diagnosis ; genetics

Each of us perceives risk differently, and so do our patients. This perception of risk gets even more complex when multiple individuals and interactions are involved: the doctor, the patient-pregnant mother, the spouse-father and the foetus-unborn child. In this review, we address the relationship between different levels of information gathering, from clinical data to experiential knowledge - data, information, knowledge, perception, attitude, wisdom - and how these would impact the perception of risk and informed consent. We discuss how patients might interpret the risks of the same event differently based upon past experiences, and suggest how risk data could be presented more meaningfully for patients and family to assimilate for informed decision making. Finally, we demonstrate how patients' expectations and risk management can impact scientific research and clinical progress by way of the most topical subject of risk screening in pregnancy - non-invasive prenatal testing using cell-free DNA in maternal plasma.
Aneuploidy ; Attitude to Health ; Female ; Fetal Diseases ; diagnosis ; genetics ; Humans ; Informed Consent ; psychology ; Pregnancy ; Prenatal Diagnosis ; adverse effects ; psychology ; Risk

OBJECTIVETo track and analyze two false positive cases from non-invasive prenatal testing for potential fetal aneuploidy.

METHODSThe 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).

RESULTSThe 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].

CONCLUSIONNon-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.

Adult ; Aneuploidy ; Chromosome Aberrations ; Diagnostic Errors ; False Positive Reactions ; Female ; Fetal Diseases ; diagnosis ; genetics ; Humans ; Pregnancy ; Prenatal Diagnosis ; Young Adult