Cytogenetic analysis in 100 spontaneous abortions in North-East Scotland

The results of an extremely detailed cytogenetic analysis on 100 spontaneous abortions occurring in the Aberdeen area over a 3 year period is presented. A comparison with other published series reveals that there is a higher culture success rate (93%) accompanied by a lower incidence of trisomy and a higher incidence of triploidy, although the percentage of chromosomally abnormal foetuses in first trimester abortions is comparable with other studies. However, these apparent discrepancies can largely be explained on the basis of gestational age and sampling variation.     

Somatic mosaicism in inborn errors of immunity: Current knowledge,challenges, and future perspectives

Inborn errors of immunity (IEI) are a diverse group of monogenic disorders of the immune system due to germline variants in genes important for the immune response. Over the past decade there has been increasing recognition that acquired somatic variants present in a subset of cells can also lead to immune disorders or ‘phenocopies’ of IEI. Discovery of somatic mosaicism causing IEI has largely arisen from investigation of seemingly sporadic cases of IEI with predominant symptoms of autoinflammation and/or autoimmunity in which germline disease-causing variants are not detected. Disease-causing somatic mosaicism has been identified in genes that also cause germline IEI, such as FAS, and in genes without significant corresponding germline disease, such as UBA1 and TLR8. There are challenges in detecting low-level somatic variants, and it is likely that the extent of the somatic mosaicism causing IEI is largely uncharted. Here we review the field of somatic mosaicism leading to IEI and discuss challenges and methods for somatic variant detection, including diagnostic approaches for molecular diagnoses of patients.     

Concurrence of Circumscribed Morphea and Segmental Vitiligo: A Case Report

Although a few reports have noted the concurrent presentation of morphea and vitiligo at distinctly separate sites in the same patient, it is extremely rare that these two conditions occur at the same sites in a patient. We report the case of a 10-year-old Korean girl with morphea and vitiligo and those lesions occurred at the same sites and progressed simultaneously. An autoimmunity and a cutaneous mosaicism was considered to be involved in such an unique presentation as the pathogenesis is concerned.     

Chromosomal integrity of human preimplantation embryos at different days post fertilization

Introduction

In order to investigate the dynamics of genomic alterations that occur at different developmental stages in vitro, we examined the chromosome content of human preimplantation embryos by molecular-cytogenetic techniques at the single-cell level, up to 13 days post fertilization.

Methods

The embryos were genetically analyzed several times during their development in culture; each embryo was first analyzed by FISH at ‘Day 3’ post fertilization, than during its growth in vitro and the third analysis was performed at development arrest, then the entire blastocyst was analyzed by comparative genomic hybridization (CGH/aCGH).

Results

We found that while on ‘Day 3’ only 31 % of the embryos were detected as normal, on ‘Day 5–6’, 44 % of the embryos were classified as normal and on ‘Day 7’, 57 % were normal. On ‘Days 8–13’, 52 % of the embryos were classified as chromosomally normal. One third of the embryos that were chromosomally abnormal on ‘Day 3’, were found to be normal at development arrest point.

Discussion

These dynamic changes that occur at early developmental stages suggest that testing a single blastomere at ‘Day 3’ post fertilization for PGD might inaccurately reflect the embryo ploidy and increase the risk of false aneuploidy diagnosis. Alternatively, blastocyst stage diagnosis may be more appropriate.     

范可尼贫血临床特征的新认识

范可尼贫血(FA)表现极大的临床异质性,尽管FA相关基因的识别拓宽了人们对于FA发病机制的认识,但除少数病例外,这些基因型与临床表现型之间缺少严格的对应性.对于同一基因型FA患者而言,突变类型对临床表现型影响似乎更为重要,修饰基因、环境因素差异等也可致FA患者临床表现明显不同.与基因型和临床表现型多样性不同,FA细胞表现型更具特征性,是诊断FA最重要的依据.     

Newly identified milder phenotype of peroxisome biogenesis disorder caused by mutated PEX3 gene

We identified the first patient with infantile Refsum disease (IRD), a milder phenotype of peroxisome biogenesis disorder (PBD) caused by a mutated PEX3, and investigated the clinical, molecular and cellular characterization in this patient. The patient presented psychomotor regression, late-onset leukodystrophy, peripheral neuropathy, hearing impairment, a renal cyst, and renal hypertension and survived until the age of 36. Furthermore, fibroblasts from the patient indicated a mosaic pattern of catalase-positive particles (peroxisomes) and numerous peroxisomal membrane structures. Molecular analysis was homozygous for the D347Y mutation and reduced gene expression of PEX3 which encodes a peroxisomal membrane protein, pex3p, involved in peroxisome assembly at the early stage of peroxisomal membrane vesicle formation, therefore, patients with a mutated PEX3 gene have been reported to have only a severe phenotype of Zellweger syndrome and no or less peroxisomal remnant membrane structure. This is not only a newly identified milder PBD caused by a mutated PEX3 gene but also the first report of a Japanese patient with IRD who had not been diagnosed until over 30 years of age, which suggests there must be more variant PBD in patients with degenerative neurologic disorder, and to bring them to light is necessary.     

Reproductive outcomes after preimplantation genetic testing in mosaic Turner syndrome: a retrospective cohort study of 100 cycles

PurposeThe purpose of this study is to explore the reproductive outcomes of women with Turner syndrome (TS) in preimplantation genetic testing (PGT) cycles.MethodsA retrospective study of 100 controlled ovarian stimulating cycles, 68 TS (sixty-four mosaic Turner syndrome (MTS) and four pure Turner syndrome (PTS)) women underwent PGT was conducted from 2013 to 2018.ResultsEmbryo X chromosome abnormal rates of TS women were significantly higher than women with normal karyotype (7.04 vs 1.61%, P<0.01). Cumulative live birth rates (CLBR) after PGT-NGS treatment were lower in TS than control (31.15 vs 45.59%, P<0.05). Clinical pregnancy rates per transfer (CPR), miscarriage rates (MR) and live birth rates per transfer (LBR) remained comparable between TS and control group. Reproductive outcomes (X chromosome abnormal rates, CPR, MR, LBR and CLBR) among low (<10%), medium (10–50%) and high (>50%) level 45,X mosaicism groups were not statistically different.ConclusionsTo avoid high risk of embryo X chromosome abnormalities, prenatal or preimplantation genetic testing should be recommended to mosaic or pure TS patients.     

Placental mosaicism in the era of chromosomal microarrays

ObjectivePlacental mosaicism for a subset of a chromosome, a structural chromosomal aberration, is thought to be a very rare finding in chorionic villus samples. Here, we present clinical and laboratory data on five cases with such mosaicism for structural chromosomal aberrations.MethodsDuring a period of 6 months, chromosomal microarray was carried out on DNA extracted from 100 uncultured chorion villous samples from high-risk pregnancies.ResultsIn five of 100 consecutively collected samples (5/100), mosaicism for a structural chromosomal aberration was detected. The mosaic aberration was subsequently detected in fetal tissue in three of the five cases.ConclusionChromosomal microarray can detect placental mosaicism for structural chromosomal aberrations. This kind of mosaicism may be more frequent than previously anticipated, and the fetal involvement seems difficult to predict. These findings highlight the complexity of mosaicism for structural chromosomal aberrations in prenatal samples in the chromosomal microarray era.     

SRY-negative 45,X/46,XY adult male with complete masculinization and infertility: A case report and review of literature

BACKGROUND45,X/46,XY mosaicism is a rare chromosomal abnormality with a wide range of phenotypes in both males and females, from normal individuals with different degrees of genital ambiguity to those who show signs of Turner’s syndrome. More rarely, cases of 45,X/46,XY mosaicism with a normal-appearing male phenotype are not found until a chromosome test is performed to investigate the cause of male infertility.CASE SUMMARYIn this study, a 29-year-old male patient with complete azoospermia is reported. Chromosomal analyses of his lymphocytes revealed the karyotype 45,X[93%]/46,X,+mar(Y)[7%]. In addition, Y chromosome-specific markers, such as SRY, ZFY, AZFa, AZFb and AZFc, were not observed in his blood DNA according to multiplex polymerase chain reaction test. A literature review identified several 45,X/46,XY cases with a normal-appearing male phenotype, most of whom were diagnosed during infertility investigation. However, the present case is the first SRY-negative 45,X/46,XY male case diagnosed during a premarital medical examination.CONCLUSIONThis finding further suggests that sex determination is a complex process regulated by multiple genetic and environmental factors.     

Perinatal outcomes of prenatal cases testing positive for trisomy 9 by noninvasive prenatal testing

ObjectivesTo evaluate the performance of non-invasive prenatal testing (NIPT) for the detection of fetal trisomy 9 in prenatal screening and to investigate the prenatal appearances and genetic counseling of trisomy 9 fetuses.Materials and methodsThe ultrasonography information, laboratory detection and pregnancy outcome of 16 cases of single pregnancy with trisomy 9 identified by NIPT who received amniocentesis in our prenatal diagnosis center from January 2018 to December 2020 were retrospectively analyzed.ResultsAmong the 16 cases, 2 cases of trisomy 9, 3 cases of trisomy 9 mosaicism, 2 cases reporting of regions of homozygosity and 9 cases of false positive were diagnosed. Among the true positive cases, 4 cases showed abnormal ultrasonic finding: 3 cases terminated pregnancy and 1 case was lost to follow-up. Another 1 case was in utero fetal demise in the second trimester without structural abnormality, and 2 cases were normal live birth without developmental abnormalities. In the 9 cases with normal kayrotyping, 1 case had termination of pregnancy and 1 case with mental retardation and poor cognitive ability, other 7 had good pregnancy outcomes.ConclusionOur results may be helpful for the selection of prenatal diagnostic strategies and genetic counseling for pregnant women with trisomy 9 revealed by NIPT.