南宁地区唐氏综合征患者的细胞遗传学研究

为了探讨中国南宁地区唐氏综合征患者染色体核型分布及其特点, 对广西壮族自治区妇幼保健院1994年以来的500例疑似唐氏综合征(Down syndrome, DS)患者进行外周血染色体核型分析, 130例确诊为DS患者。其中, 单纯型21-三体为86.15%(112/130); 易位型为8.46%(11/130); 嵌合型为5.39%(7/130)。在单纯型21-三体中性别比为女∶男=1∶1.8; 93.08% 的唐氏综合征患儿由年轻母亲(<35岁)所生, 另有6.92% 由高龄产妇所生。结果表明, 南宁地区86% 以上唐氏综合征患者的染色体核型是单纯型21-三体, 男性唐氏综合征患儿明显高于女性患儿。     

六例嵌合型Turner综合征的细胞遗传学观察

我们在进行染色体病的咨询门诊中,对39例原发性闭经患者进行了染色体检查,经核型分析确诊为45,XO单体型18例,嵌合型6例。其中45,XO/46,XX 3例,45,XO/46,Xi(Xq)1例,45,XO/46,XX(r)2例。现将6例嵌合型Turner综合征报道如下。     

六例嵌合型Turner综合征的细胞遗传学观察

我们在进行染色休病的咨询门诊中,对39 例原发性闭经患者进行了染色体检查,经核型 分析确诊为、5, XO单体型18例,嵌合型6例。 其中45, XO/46,XX 3例,45, X0/46, Xi(Xq) 1 例,45, XO/ 16, XX(r) 2例。现将6例嵌合型 Turner综合征报道如下。     

两种细胞来源的21-三体综合征诱导多能干细胞系的建立及比较

21-三体综合征是染色体异常导致的疾病,通过重编程21-三体综合征患儿两种组织来源的细胞成为多能干细胞,比较两种组织来源的细胞建立21-三体综合征诱导多能干细胞（T21-iPSCs）系的效率,为进一步研究21-三体综合征发病机制提供细胞模型,并为选择高效制备T21-iPSCs的组织类型提供理论依据。该实验利用慢病毒介导4种转录因子（Oct4、Sox2、Klf4、c-Myc）分别诱导人21-三体综合征的羊水细胞和胎儿皮肤成纤维细胞,建立诱导多能干细胞系（Trisomy 21 human amniotic fl uid induced pluripotent stem cells,T21 hAF-iPSCs;Trisomy 21 human dermal fi broblast induced pluripotent stem cells,T21 hDF-iPSCs）,T21 hAF-iPSCs及T21 hDF-iPSCs在蛋白和mRNA水平上均表达人胚胎干细胞的多能性分子标记,如Oct4、Nanog等,具有在体外及体内分化三个胚层的能力,其在培养过程中能维持异常核型并能维持自我更新状态。结果发现,利用羊水细胞建立T21-iPSCs效率高于皮肤成纤维细胞,羊水细胞可能是制备T21-iPSCs的理想细胞类型。     

内葵杂3号染色体核型分析

对内蒙古地区的栽培品种内葵杂3号三交种和单交种了进行了核型分析。其结果为:内葵杂3号三交种和单交种的染色体数均为2n=34,各具一对随体染色体。三交种第2对染色体具随体且为近中部着丝粒染色体,其余为中部着丝粒染色体,染色体相对长度变异范围4.105%～7.703%,核型公式为2n=2x=34=32m+2sm(2sat),核型类型属于1A型;单交种均为中部着丝粒染色体,第4对染色体具随体,染色体相对长度变异范围3.661%～8.128%,其核型公式为:2n=2x=34=34m(2sat),核型类型属于1B型。     

21- 三体综合征亲子鉴定一例暨文献复习

目的:对亲子鉴定中检出的三带型等位基因座进一步探讨其发生原因,与同行共享。方法:亲子鉴定中发现一个体两个等位基因座(D21S11和Penta D)检出三等位基因,进一步采集其静脉血进行血细胞培养作染色体分析。结果:该个体染色体核型为:47,XY,+21。结论:染色体为三体型的个体在基因检测时能检测到三等位基因。     

黑龙江地区466例孕妇羊水穿刺产前诊断结果分析

目的:探讨羊水细胞染色体异常核型与各产前诊断之间的关系。方法:466例高危孕妇行羊膜腔穿刺术后羊水细胞培养及染色体核型分析。结果:异常核型66例,异常率14.16%,包括染色体数目异常27例,三体综合征22例(21-三体15例、18-三体6例、13-三体1例),占异常染色体核型的33.33%,占染色体数目异常的81.48%;染色体结构异常39例,主要包括染色体多态性、平衡易位、倒位和衍生等,占染色体异常核型的59.10%。异常核型检出率中血清学筛查高危组(14.44%)要高于高龄妊娠组(10.89%)和有不良孕产史组(11.11%)(P0.05);超声提示胎儿发育异常组(23.26%)要高于血清筛查高危组(P0.05)。结论:血清筛查高危和超声提示胎儿发育异常是黑龙江地区最主要的产前诊断指征,异常核型以21-三体综合征检出率最高。通过对高危孕妇羊水细胞染色体的核型分析可发现部分染色体疾病,从而避免此类出生缺陷儿的出生。     

我国某些蔷薇属花卉的核型研究

本文报道了我国产的5种和14个品种的蔷薇属花卉的染色体数目和核型,结果如下:小花型为二倍体,2n=2x=14,少数为混倍体;中花型为三倍体,2n=3x=21;大花型为四倍体,2n=4x=28。大部分种的核型均由其中部和近中部着丝点染色体组成,少数种具近端着丝点染色体。它们可以区分为3种核型类型,即1A、2A和1B。     

一例45,X/46,XY嵌合型Turner综合征的临床和细胞遗传学研究

本文报道了一例45,X/46,XY嵌合型Turner综合征的病例,并进行了外周血淋巴细胞、两侧性腺及皮肤成纤维细胞培养及其核型分析。对核型及表型的关系,肿瘤的发生率以及45,X/46,XY嵌合体息者的性腺发育和分化,进行了讨论。     

一例13/21易位型先天愚型

先夭愚型是一种最常见的常染色体疾病,在细胞遗传学上,可分为三体型、易位型和嵌合型。易位型的先天愚型在国内用分带技术进行研究的报道较少^[1,2]。我们发现一例13/21型的先天愚型。     

Down's syndrome: chromosome analysis of 362 cases in Hungary.

A survey is given of the karyotypes observed in 362 children clinically diagnosed as cases of Down's syndrome from whom material was sent to 8 collaborating cytogenic laboratories in Hungary during the period 1965-1974. The sample studied cytogenetically constitutes about 20% of all children born in Hungary in this decade with Down's syndrome. The ways in which patients were selected for cytogenetic examinations could not be specified. In the sample, standard trisomy 21 was found in 91.7%, translocations in 3.9% and mosaicism in 4.4%. The mean age of the mothers of the children investigated was 29.05 years, a relatively low figure which may be explained by the decrease of the mean maternal age over the last decades.     

Chromosomal disorders in women with spontaneous abortions

The results of examination of 120 women with spontaneous abortions are presented. The cytogenetic analysis showed that in karyotypes of the patients there are chromosome aberrations of different types: translocations (17.5%), monosomy (13.3%), trisomy (10%), mosaicism (5.8%) and other forms (4.1%). Phenotypic manifestation of chromosome anomalies with spontaneous miscarriages (abortions) is discussed in the work.     

DNA polymorphism analysis in families with recurrence of free trisomy 21

We used DNA polymorphic markers on the long arm of human chromosome 21 in order to determine the parental and meiotic origin of the extra chromosome 21 in families with recurrent free trisomy 21. A total of 22 families were studied, 13 in which the individuals with trisomy 21 were siblings (category 1), four families in which the individuals with trisomy 21 were second-degree relatives (category 2), and five families in which the individuals with trisomy 21 were third-degree relatives, that is, their parents were siblings (category 3). In five category 1 families, parental mosaicism was detected, while in the remaining eight families, the origin of nondisjunction was maternal. In two of the four families of category 2 the nondisjunctions originated in individuals who were related. In only one of five category 3 families, the nondisjunctions originated in related individuals. These results suggest that parental mosaicism is an important etiologic factor in recurrent free trisomy 21 (5 of 22 families) and that chance alone can explain the recurrent trisomy 21 in many of the remaining families (14 of 22 families). However, in a small number of families (3 of 22), a familial predisposing factor or undetected mosaicism cannot be excluded.     

Dermatoglyphic studies in the parents of trisomy 21 children I. Distribution of dermatoglyphic discriminants

A sample of 312 parents of a child with complete trisomy 21 (168 mothers and 144 fathers) has been compared with 295 parents of non-mongol children (61 mothers and 134 fathers) with respect to distribution of individual dermatoglyphic discriminant scores. Selection of dermatoglyphic traits as well a weightings have been based on the discriminant function, constructed for normal controls against cytogenetically diagnosed trisomy 21 mosaics. The results indicate that the proportion of individuals with an increased chance of mosaicism is appreciably greater in a sample of both the mothers and the fathers of mongol children, as compared with the parents of non-mongol children. For D greater than + 3.00, including also the overlap range values, it is, on the average, twice as high as in the control parents, while for the D values greater than + 4.00, strongly indicative of mosaicism, it is about five times higher than in control parents. This is so in spite of the fact that all parents, who had previously been cytogenetically tested and diagnosed as mosaics, were not included in this sample. Although the meaning of these results cannot yet be completely understood, they justify the extension of the use of dermatoglyphic discriminants in studies on parental mosaicism in trisomy 21.     

A clinical and cytogenetic investigation carried out in a special institution for mentally retarded patients: preliminary results concerning 82 cases of oligophrenia (author's transl)]

A clinical and cytogenetic investigation carried out in a special institution for mentally retarded patients revealed 82 cases of oligophrenia, amongst whom were found 56 normal karyotypes (68.3%). Out of 25 karyotypes with chromosome anomalies or variants there were 18 cases of trisomy 21 and 7 others: one case of mosaicism with balanced translocation, 46,XX/46,XX,6p+,17q-; one case of partial trisomy, 46,XX,11q+; one case of pericentric inversion, 46,XY,inv(1) (p13,q21); one case with 8% chromosome breaks; three cases of marker chromosomes, of which one was of karyotype 46,XX,1qh+, and two (oligophrenic sisters) 46,XX,21p+. Moreover, there was an interesting case of testicular feminisation in a 9-year-old girl with karyotype 46,XY. The authors' results corroborate those obtained in several important previous studies based on much larger numbers of patients. Amongst the 56 cases where the karyotype was shown to be normal, there were 15 for whom a probably exogenic cause of the oligophrenia could be established, occurring mainly during the perinatal period. The authors were also able to confirm that the genetic factor plays an important role in the incidence of mental retardation, since in 22 examined patients, i.e. 26.8% of all cases, the condition was of familial type. Some interesting observations of idiopathic oligophrenia are reported, as well as several cases with well-known syndromes (Crouzon's and Cornelia de Lange's syndromes, hypothyroidism). Two cases of incest between father and daughter, which had produced children with serious oligophrenia associated, in one case, with deaf-mutism, microphthalmia, microcephaly and sclerocornea, are also discussed. The data show that mental retardation can frequently have a genetic cause, either of mendelian, chromosomal or multifactorial origin.     

Down's syndrome in brother and sister without evident trisomy 21

Summary In the present report two siblings with the typical Down's phenotype but without evident full or partial 21 trisomy are described. The finding of a regular 21 trisomy in a minority of the cells in the elder patient favors the hypothesis that both present a hardly demonstrable normal/trisomy 21 mosaicism and may be examples of a constitutional familial tendency to nondisjunction in man.     

Incidence of major chromosome aberrations in 12,319 newborn infants in Tokyo

Summary In order to ascertain the frequency of chromosome aberrations among newborn infants in Japan, a chromosome survey of a large number of newborn infants is in progress. A consecutive series of 12,319 newborn babies, 6382 male and 5937 female, have been screened for clinical manifestations of autosomal aberrations and for sex chromatin and sex chromosome aberrations. Chromosome studies were carried out on 694 infants with suspected chromosome aberrations. The clinically abnormal infants were screened by conventional staining, and banding techniques have been used in the part of the study performed since 1974. Of the clincally abnormal infants, 25 had abnormal karyotypes, including two males with a 47,XXY complement, one female with a 45,X complement, three male infants with a 47,XYY complement, two with trisomy 13 syndrome, three with trisomy 18 (including one case of mosaicism), eleven with Down's syndrome (including one case of mosaicism), one with B5p partial trisomy, one with cri-du-chat syndrome, and one with Y/D translocation. The overall results are comparable to those of previous population cytogenetic studies only in the autosomal trisomies and sex chromosome abnormalities and in that the observed frequencies were comparable to those found in studies in Caucasians.To whom offprint requests should be sent     

Partial monosomy 8p and partial trisomy 8p with moderate mental retardation.

A female patient with mosaicism for partial monosomy 8p and partial trisomy 8p is presented. Her karyotype is 46,XX, del(8)(p21)/46,XX, dup(8)(p21----pter). She showed minimal dysmorphic features, agenesis of the corpus callosum and moderate developmental delay. There is no previous report of mosaicism for partial monosomy and partial trisomy 8p. The clinical findings in the presently described patient are less severe than those reported in cases with only monosomy or trisomy of the distal part of chromosome 8.     

Parental trisomy 21 mosaicism.

A family with three children with trisomy 21 in which the mother is a phenotypically normal, trisomy 21/normal mosaic was studied. Chromosome 21 fluorescent heteromorphisms were used to document that two of the three number 21's in two of the Down syndrome offspring were of maternal origin. Five cytogenetic surveys in which both parents of a child with trisomy 21 were studied have been reviewed. From these data, it is estimated that 3% of couples producing a child with trisomy 21 can be explained by parental mosaicism. From 17 informative sibships, with one parent mosaic, the segregation ratio was estimated to be 0.43 +/- 0.11.     

Chromosomal mosaicism in amniotic fluid cell cultures.

Over the past 6 years, using in situ processing methods, we have identified 32 cases of mosaicism in amniotic fluid cell cultures prepared from 1,100 samples. Two of these (45,X/46,XX and 46,XX/47,XX, + 21) were called true mosaics because multiple colonies demonstrated the same abnormal chromosome complement, and on subsequent evaluation of the newborn blood or fetal tissues, mosaicism was confirmed. Of the remaining cases, 29 were designated as pseudomosaics because only single or partial colonies exhibited an aberrant chromosome complement, 12 having a trisomy 2 line. In the final case, a double trisomy was demonstrated in only one of eight colonies in the first culture, but in the culture from a repeat sample an additional two colonies showed the same double trisomy. Since no abnormal cells were observed in infant blood, it was postulated that the mosaicism may only have been present in the extraembryonic tissues. It is our conviction that the use of these cloning methods should diminish the danger of misdiagnosis in genetic amniocentesis.