回复镶嵌现象与隐性营养不良型大疱性表皮松解症治疗的研究进展

隐性营养不良型大疱性表皮松解症是一种遗传性水疱病,由编码Ⅶ型胶原的基因突变引起,对患者生活质量有很大影响,目前治疗多为对症处理,迫切需要更好的治疗方法.近年研究发现,隐性营养不良型大疱性表皮松解症患者存在回复突变所致的片状外观正常皮肤.这种现象称为回复镶嵌现象,也称为天然基因治疗.这一发现开启了回复细胞治疗的可能性,即回复的角质形成细胞体外培养移植到受损皮肤.假如结合患者特异性诱导性多能干细胞方法,可以有机会培养出大片健康皮肤移植物.另外,回复体来源的诱导性多能干细胞还可以分化为造血细胞和间质干细胞,骨髓移植后归巢到水疱区域,即“从皮肤到血细胞,再修复皮肤”.     

An unexpected finding in a child with neurological problems: mosaic ring chromosome 18

Major neurological disorders may accompany rare chromosomal abnormalities. As an example of this rare condition, we present a case with microcephaly, mental retardation, developmental delay, hyperactivity, stereotypic movements, seizures and dysmorphic facial appearance in whom a mosaic ring chromosome 18 was found [45,XX,-18/46,XX,r(18)/46,XX,dicr(18)]. Although ring chromosome 18 phenotype has been known for a long time, this is the third reported patient with a dicentric ring chromosome 18 mosaicism. The presented case will contribute to the identification of the genotype-phenotype correlation in chromosome 18 anomalies.     

A new case of mosaicism for invdup(15) duplicated for Prader-Willi/Angelman syndrome critical region (PWACR) in an adult healthy man

Supernumerary invdup(15) chromosomes, now also reported as sSMC(15), containing two additional copies of Prader–Willi/Angelman critical region (PWACR) have been associated with distinct clinical phenotype that includes hypotonia, dysmorphisms, developmental delay/mental retardation, autistic behaviour, and epilepsy.

We report on a healthy adult male carrying an sSMC(15) with two copies of PWACR in 20–50% of cells from different tissues. Molecular analyses showed the sSMC(15) as resulting from a PWACR-duplicated region spanning 8 Mb which is larger than those in the only two other healthy PWACR-duplicated sSMC(15) carriers previously reported.

Mosaicism level and mosaic cell line rate variation among different tissues observed in our case support mosaicism in critical tissues as of relevance for sSMC(15) phenotype–genotype correlations.     

Cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes in mosaic double trisomy involving trisomy 7 and trisomy 20 (48,XY,+7,+20) at amniocentesis

ObjectiveWe present mosaic double trisomy involving trisomy 7 and trisomy 20 at amniocentesis in a pregnancy with a favorable outcome.Case reportA 41-year-old woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a result of 48,XY,+7,+20[6]/46,XY[26] in cultured amniocytes. At 19 weeks of gestation, repeat amniocentesis was performed, which revealed a result of 48,XY,+7,+20[4]/46,XY[21] in cultured amniocytes. Simultaneous molecular cytogenetic analyses on uncultured amniocytes at repeat amniocentesis revealed no genomic imbalance in array comparative genomic hybridization (aCGH) analysis, no trisomy 7 and no trisomy 20 signals in 114/114 cells in interphase fluorescence in situ hybridization (FISH) analysis, and no uniparental disomy (UPD) 7 and no UPD 20 in quantitative fluorescent polymerase chain reaction (QF-PCR) analysis. Interphase FISH analysis on cultured amniocytes revealed double trisomy of trisomy 7 and trisomy 20 in 5/105 cells (4.7%) compared with 0/100 cells (0%) in the normal control. Prenatal ultrasound findings were unremarkable. The parental karyotypes were normal. The woman decided to continue the pregnancy, and a healthy 2880-g phenotypically normal male baby was delivered at 34 weeks of gestation without any structural abnormality. The cord blood had a normal karyotype. Interphase FISH analysis of the urinary cells revealed no trisomy 7 and no trisomy 20 signals in 51/51 urinary cells.ConclusionCytogenetic discrepancy between cultured amniocytes and uncultured amniocytes can occur in mosaicism for double trisomy involving trisomy 7 and trisomy 20 at amniocentesis. Molecular cytogenetic analyses such as aCGH, FISH and QF-PCR on uncultured amniocytes are useful for rapid distinguishing true mosaicism from pseudomosaicism under such a circumstance.     

Could PGT-A pick up true abnormalities that have clinical relevance? Retrospective analysis of 1043 embryos

ObjectiveTo determine whether preimplantation genetic testing for aneuploidy (PGT-A) could pick up true abnormalities that have clinical relevance.Materials and methodsThis was a retrospective cohort study of patients who underwent in vitro fertilization with PGT-A from 2015 to 2017. We evaluated the associations of aneuploidy and mosaicism with maternal age, the chromosome abnormalities present in individual chromosomes, and the effect of embryo sex on the proportion of each type of error in the four chromosomes most frequently affected.Result(s)A total of 1043 embryos from 255 patients (mean maternal age = 39 ± 4 years) were included in the initial analysis. Of these, 36% (377/1043) were euploid, 47% (487/1043) were aneuploid, 13% (140/1043) contained mosaicism, and 4% (39/1043) gave no result. We excluded the 39 embryos with no result; thus, 1004 embryos were included in the analysis. Increased aneuploidy was associated with increased maternal age, but the rate of embryo mosaicism was not. A combined analysis of aneuploidy with noncomplex abnormalities and mosaicism showed that chromosomes 22, 21, 16, and 15 were the most frequently involved. Chromosome 22 showed the highest proportion of mosaicism and chromosome 15 showed the highest proportion of aneuploidy. When we included embryo sex in the analysis, embryo sex was associated with these chromosome errors in the most susceptible chromosome, 22.Conclusion(s)PGT-A showed that chromosomes 22, 21, 16, and 15 were the most frequently involved among common chromosome abnormalities, comparable with those of published data analyzed from spontaneous abortion. This result suggested that PGT-A could pick up abnormalities that have clinical relevance to spontaneous abortion. Moreover, we identified a role of embryo sex in these chromosomal errors on chromosome 22.     

Mosaicism of mitochondria in mitochondrial myopathy: an electronmicroscopic analysis of cytochrome c oxidase

Summary Electron microscopic histochemistry was applied to the study of cytochrome c oxidase activity in each mitochondrion of biopsied muscles from four patients with mitochondrial myopathy [one case of fatal infantile mitochondrial myopathy, one case of myoclonus epilepsy associated with ragged-red fibers (MERRF), and two cases of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS)]. In the patient with fatal infantile mitochondrial myopathy, intercellular heterogeneity of mitochondria was recognized. In the three patients with either MERRF or MELAS, cytochrome c oxidase activity was segmentally changed from positive to negative within single muscle fibers. In the two patients with MELAS, small groups of positive-stained mitochondria were located among negative-stained mitochondria in the negative segment of a few muscle fibers. These findings revealed that there were heterogeneous populations of normal and abnormal mitochondria intracellularly or intercellularly within the muscles of these patients.Supported in part by Grant-in-Aid for Scientific Research 63570422 from the Ministry of Education, Science and Culture, and Grant 62A-5-08 from the National Center of Neurology and Psychiatry (NCNP) of the Ministry of Health and Welfare, Japan     

Linear Darier's disease in a patient with recurrent carcinoma of the bladder reflects cutaneous mosaicism

We report a case where occurrence of linear Darier's disease along Blaschko's lines followed radiotherapy due to the subject's recurrence of a longstanding carcinoma of the bladder. Scattered papules on the chest and hack preceded the exacerbation of the disease. In this case, localised linear disease may he triggered on a background of a more disseminated disease which raises the possibility that linear keratosis follicularis is a separate entity of cutaneous mosaicism for the mutation responsible for Darter's disease.     

Trisomy 8 mosaicism

A 16-year-old boy with trisomy 8 mosaicism is presented. Increased birth weight, delayed psychomotoric and accelerated somatic development, and mental retardation were noted; he exhibited a prominent forehead, a broad-bridged upturned nose, an everted lower lip, low set dysmorphic ears, strabismus, slender trunk, narrow pelvis, osseous and joint anomalies, clinodactyly, deep skin furrows on the soles, and agenesis of the corpus callosum. The trisomic cell line was observed throughout the follow-up examinations from the fibroblast cultures between 1962 and 1973, but has disappeared from the lymphocyte culture.The clinical picture of this case is compared with the leading clinical signs and symptoms of the 25 cases with confirmed trisomy 8 so far published. A scheme is proposed in order to keep in mind the clinical picture suggesting trisomy 8.     

Genetic analysis for 2 females carrying idic(Y)(p) and with sex development disorders北大核心CSCD

Objective: To investigate the phenotype-genotype association of isodicentromere Y chromosome by analysis of two female patients carrying the chromosome with sexual development disorders. Methods: The karyotypes of the two patients were determined by application of conventional G banding of peripheral blood samples and fluorescence in situ hybridization (FISH). PCR was applied to detect the presence of SRY gene. Results: Conventional karyotype analysis showed case 1 to be a mosaic: mos. 45,X[38]/46,X,+mar[151]/47,XY,+mar[5]/47,X,+marX2[2]/46,XY[4], FISH showed that 12 different cell lines were presented in the karyotype of case 1 and partial cell lines with SRY gene, the marker is an isodicentromere Y chromosome[idic(Y)(p)]. No mutation was found in the SRY gene. The karyotype of case 2 was mos. 45,X[25]/46,X,+mar[35]. FISH showed the marker to be an idic(Y)(p) without the SRY gene. Conclusion: The karyotype of patients carrying idic(Y)(p) seems unstable, and female patients have the characteristics of short stature and secondary sexual hypoplasia. Karyotype analysis combined with FISH analysis can accurately determine the breakpoint of idic(Y) and identify the types of complex mosaic, which may facilitate genetic counseling and prognosis. © 2016, West China University of Medical Sciences. All rights reserved.