两例Turner综合征患者微小额外标记染色体来源鉴定

目的 为指导遗传咨询和临床治疗,对两例特纳综合征患者微小额外标记染色体(small supernumerary marker chromosome,sSMC)来源进行鉴定.方法 高分辨染色体G显带和C显带核型分析;PCR扩增SRY基因;中期染色体荧光原位杂交.结果 两例患者核型分析结果分别为45,X[29]/46,X,+mar[31]和45,X[71]/46,X,+mar[29].病例1 SRY基因检测阳性,其sSMC来源于Y染色体,通过荧光原位杂交最终确定其核型为45,X[29]/46,X,idic(Y)(q10)[31].ish idic(Y)(q10)(RP11-115 H13 ×2)(SRY+).病例2 sSMC来源于X染色体,核型最终确定为45,X[713/46,X,r(X)(p11.23q21)[29]ish r(X)(p11.23q21)(AL591394.11+,AC 092268.3-).结论 联合应用多种遗传学检测技术,准确鉴定了两例特纳综合征患者微小额外标记染色体的来源,以正确指导临床诊断和治疗.     

Detection and incidence of cryptic Y chromosome sequences in Turner syndrome patients

The presence of Y chromosome sequences in Turner syndrome (TS) patients may predispose them to gonadoblastoma formation with an estimated risk of 15–25%. The aim of this study was to determine the presence and the incidence of cryptic Y chromosome material in the genome of TS patients. The methodology involved a combination of polymerase chain reaction (PCR) and nested PCR followed by Southern blot analysis of three genes—the sex determining region Y (SRY), testis specific protein Y encoded (TSPY) and RNA binding motif protein (RBM) (previously designated as YRRM) and nine additional STSs spanning all seven intervals of the Y chromosome. The methodology has a high sensitivity as it detects one 46, XY cell among 10⁵ 46, XX cells. Reliability was ensured by taking several precautions to avoid false positive results. We report the results of screening 50 TS patients and the identification of cryptic Y chromosome material in 12 (24%) of them. Karyotypes were divided in four groups: 5 (23.8%) patients out of the 21 TS patients which have the 45, X karyotype (group A) also have cryptic Y sequences; none (0%) of the 7 patients who have karyotypes with anomalies on one of the X chromosomes have Y mosaicism (group B); 1 (6.3%) of the 16 patients with a mosaic karyotype have Y material (group C); and 6 (100%) out of 6 patients with a supernumerary marker chromosome (SMC) have Y chromosome sequences (group D). Nine of the 12 patients positive for cryptic Y material were recalled for a repeat study. Following new DNA extraction, molecular analysis was repeated and, in conjunction with fluorescent in situ hybridization (FISH) analysis using the Y centromeric specific probe Yc-2, confirmed the initial positive DNA findings. This study used a reliable and sensitive methodology to identify the presence of Y chromosome material in TS patients thus providing not only a better estimate of a patient's risk in developing either gonadoblastoma or another form of gonadal tumor but also the overall incidence of cryptic Y mosaicism.     

Supernumerary marker chromosomes derived from chromosome 15: analysis of 32 new cases

Small supernumerary marker chromosomes (SMC) are a heterogeneous group of chromosomes with an estimated frequency of approximately 0.14-0.72 per 1000 newborns and higher frequencies in particular populations such as the mentally retarded or infertile males. With a frequency of about 50%, derivatives of chromosome 15 represent the most common SMC. Here we present the results of a detailed analysis of 32 SMC(15) carriers who were ascertained in pre- or post-natal routine cytogenetic diagnostics. SMC(15) with euchromatic content led to mental and psychomotor retardation. In contrast, SMC(15) without euchromatin were found to have no influence on the carrier's phenotype but were detected with a high incidence among infertile males. The majority of SMC(15) are pseudodicentric homologous rearrangements. Based on our investigations a further characterization of der(15) was possible.     

Analysis of sex chromosome aneuploidy in 41 patients with Turner syndrome: a study of 'hidden' mosaicism

We performed a genetic study of sex chromosome mosaicism in 41 Turner syndrome patients. The investigation was carried out in four phases: cytogenetics (G-banding), FISH, PCR for SRY in all 41 cases, and sequencing of the SRY gene in the 2 patients with the Y chromosome. The application of classical alpha-satellite probes (CEP-X and CEP-Y), painting probes (WCP-X and WCP-Y) and also XIST, DXZ4 and two subchromosomal painting libraries (SCPL 116 and SCPL102) covering the short and the long arm of the X chromosome, respectively, allowed us to find new mosaic cell lines (mosaicism) in 37 out of 41 patients; only 4 patients were defined as 45,X non-mosaic. The most frequent hidden mosaic was 45,X/46,XX in 32% of the cases; the presence of isochromosomes comprised 25% and markers 5%. The patients who had been previously diagnosed as mosaics displayed a higher complexity in their karyotypes due to the presence of new cell lines. The Y chromosome and the SRY gene were present in blood and ovarian tissue in 2 patients with karyotypes 45,X/46,XY and 45,X/46,X,idic(Ynf). In both patients, the sequencing of the SRY gene confirmed a nucleotide sequence identical to that of a control male. Our results support the hypothesis of 'the necessity of mosaicism for survival', and thus, a mitotic origin for this syndrome.     

45,X/46,X,+mar核型Turner综合征患儿额外小标记染色体来源和形态研究

遗传学特征,以指导遗传咨询、产前诊断和确定临床治疗方案.     

A molecular and FISH analysis of structurally abnormal Y chromosomes in patients with Turner syndrome

Fourteen patients with Turner syndrome and a structurally abnormal Y chromosome were analysed by PCR amplification and fluorescence in situ hybridisation for the presence of sequences specific to defined regions of the Y chromosome. Thirteen patients had a mosaic karyotype including a 45,X cell line and one case was non-mosaic in cultured lymphocytes. Ten patients had a pseudodicentric Yp chromosome, two an isodicentric Yq, one a pseudodicentric Yq, and one a derived Y chromosome. Two of the patients with a psu dic(Yp) chromosome had complex karyotypes with more than two cell lines, one of which exhibited five morphologically distinct mar(Y) chromosomes, presumably derived from a progenitor psu dic(Yp). Nine of the ten psu dic(Yp) chromosomes were positive for all Yp and Yq probes used except DYZ1 which maps to Yq12, suggesting a common breakpoint near the Yq euchromatin/heterochromatin boundary. In the three patients with a dicentric Yq chromosome two different breakpoints were observed; in two it was between PABY and the subtelomeric repeat sequence and in one it was between DYZ5 and AMGY in proximal Yp. Our results suggest that the great majority of structurally abnormal Y chromosomes found in Turner syndrome mosaics contain two copies of virtually all of the functional Y chromosome euchromatin.     

Parental origin of the X chromosome, X chromosome mosaicism and screening for "hidden" Y chromosome in 45,X Turner syndrome ascertained cytogenetically

Our study confirms the finding that about 85% of X chromosomes in Turner girls are maternally derived. A new observation is the detection of a high frequency of mosaicism (15%) in Turner girls who by cytogenetic analysis were thought to have a pure 45,X karyotype. DNA examination of the material was done by hybridization with digoxigenin labelled, non-radioactive probes, and PCR products for microsatellite analysis were run on polyacrylamide gels. We screened for the presence of "hidden" Y chromosome mosaicism, using the primers SRY, ZFY, DYZ3, DYZ1 and DYS132. Contrary to other reports using the PCR technique to unravel "hidden" Y chromosome mosaics, we did not find any positive cases. A precise technical protocol for these new techniques is given, and the advantages are discussed.     

Turner综合征患儿标记染色体的来源研究

目的 了解Turner综合征患儿标记染色体的来源，以指导遗传咨询及治疗。方法 在染色体核型分析的基础上，对32例Turner综合征患者进行回顾性分析。对3例含有标记染色体的患儿进一步用荧光原位杂交技术研究标记染色体的来源。结果 3例含有标记染色体的Turner综合征患儿中，确定1例患儿的标记染色体来源于Y染色体，含有性别决定基因；1例来源于X染色体；另外1例未能确定其来源，该标记染色体可能来源于性染色体的其他片段或其他端着丝粒染色体。结论 Turner综合征患者的标记染色体大多来源于性染色体（X染色体、Y染色体），也可能来源于其他端着丝粒染色体。有必要同时应用X染色体和Y染色体特异性探针对Turner综合征患者进行标记染色体的荧光原位杂交分析，以明确标记染色体的来源。     

Cat-eye syndrome with unusual marker chromosome probably not chromosome 22

An unusual supernumerary chromosome with a single satellite on the long arm was found in a child with manifestations of the cat-eye syndrome including apparently low-set and malformed ears, preauricular tags, micrognathia, and imperforate anus. Although G-banding suggested that this extra material was chromosome 22, this was not confirmed by several other banding techniques. After examination of the parents' chromosomes, the nature and origin of this extra chromosome remains obscure. We conclude that patients previously diagnosed as having “partial trisomy 22” with incomplete cat-eye syndrome may have a different chromosome constitution when studied by various banding techniques.     

Novel ring chromosome composed of X‐ and Y‐derived material in a girl with manifestations of Ullrich‐Turner syndrome

We present a female infant who has a novel genetic variant of Ullrich‐Turner syndrome. Chromosome analysis on amniotic fluid cells obtained because of ultrasound observation of nuchal thickening showed 45,X in all cells. The infant was born with a low posterior hairline and moderate edema over hands and feet. Postnatal chromosome analysis demonstrated two cell lines—47% of the metaphases were 45,X, but 53% had a ring chromosome in addition to the normal X. FISH studies using alpha satellite probes, an X‐whole‐chromosome‐paint (WCP) probe, and a Y‐cocktail probe determined that the ring was composed of both X and Y sequences. FISH studies also determined that the KAL locus was present on the ring, but that XIST was absent. PCR‐based analysis of lymphocyte DNA documented that the ring contained sequences from both the short and the long arm of the Y chromosome. X‐chromosome analysis using a panel of highly polymorphic markers indicated that the ring contained material derived only from Xp22.1 to Xp21.3. No Xq material was identified on the ring, and androgen receptor‐based X‐inactivation studies suggested that the intact X chromosome was not subject to random X inactivation. Am. J. Med. Genet. 93:343–348, 2000. © 2000 Wiley‐Liss, Inc.     

Molecular mapping of an idic(Yp) chromosome in an Ullrich‐Turner patient

We describe a woman with Ullrich‐Turner manifestations and a 45,X/46,X,+mar karyotype. Fluorescence in situ hybridization (FISH) and DNA analysis were carried out in order to determine the origin and structure of the marker. FISH showed that the marker was a Y‐derived dicentric chromosome. The breakpoint at Yq11 (interval 6) was mapped using Southern blotting and polymerase chain reaction (PCR). There were no nucleotide alterations in the SRY conserved domain. Histological analysis of the gonads showed an ovarian‐like stroma with no signs of testicular tissue. These findings indicate that the patient was a mosaic 45,X/46,X,idic(Yp) whose phenotypic expression, including sex determination, appeared to have had more influence from the 45,X cell line. Am. J. Med. Genet. 91:95–98, 2000. © 2000 Wiley‐Liss, Inc.     

Usefulness of imprint cytology of gonadoblastoma with dysgerminoma in a patient with Turner syndrome and a Y chromosome: A case report and literature review

Ovarian gonadoblastoma coexisting with a dysgerminoma is extremely rare in patients with Turner syndrome (TS) and a Y chromosome. The cytological findings, including imprint cytology, of these unusual ovarian tumors have rarely been reported. We report a rare patient with a gonadoblastoma with dysgerminoma, 3.0 × 2.0 cm in size; she was a 19‐year‐old woman with TS and a Y chromosome. She underwent laparoscopic bilateral gonadectomy, and the tumor was classified as stage IA (pT1aNxM0) according to the International Federation of Gynecology and Obstetrics classification system. Intraoperative imprint cytology revealed two types of neoplastic cells: small tumor cells surrounding light green‐stained or eosinophilic hyaline globules with marked calcification, suspicious for gonadoblastoma; and large, round, atypical cells with abundant cytoplasm, macronucleoli, and marked lymphocytic infiltration (two‐cell pattern), suspicious for dysgerminoma. The cytology results in our patient may represent the second reported results of imprint cytology describing a gonadoblastoma with dysgerminoma. They are the first reported results in a patient with TS and a Y chromosome.     

Two male patients with ring Y: definition of an interval in Yq contributing to Turner syndrome

Turner syndrome is thought to result from the haploinsufficiency of genes on the sex chromosomes, but these genes have not been identified yet. We describe two males with deleted ring Y chromosomes, one (TS) with full Turner syndrome and one (DM) without. TS has short stature, skeletal anomalies, lymphogenic obstruction, cardiovascular abnormalities, and miscellaneous features including pigmented naevi, antimongoloid slanting of the palpebral fissures, and widely spaced nipples. In contrast, DM has short stature but no other specific Turner stigmata except high arched palate and a few pigmented naevi. Since little chromosomal mosaicism was detected, the different segments of the Y chromosome retained by these two males identify the location of one or more "anti-Turner" genes. Most of the Yp pseudoautosomal region and Yq were deleted from both patients during the formation of the ring chromosome, while the Y specific portion of Yp and the centromere were retained. The major difference detected was an interval of proximal Yq present in DM and deleted in TS. None of the previously identified genes, DFFRY, DBY, UTY, or TB4Y, lies entirely within this interval, although DFFRY was truncated by DM's breakpoint. These data suggest that one or more additional "anti-Turner" gene(s) remains to be identified in the region of Yq proximal to DFFRY.     

A supernumerary marker chromosome originating from two different regions of chromosome 18

By random amplification of a microdissected chromosome using the degenerate oligonucleotide primed polymerase chain reaction (DOP-PCR) and forward painting (microFISH), we characterised an extra structurally abnormal chromosome (ESAC) or supernumerary marker chromosome in a mentally retarded girl with a pattern of dysmorphic features. It could be clearly shown that the small marker chromosome originates from two different regions of chromosome 18, 18p11.1-->18q11.1 and 18q12.3-->18q21.1 respectively. Maternal origin of the de novo ESAC and biparental origin of the normal homologues of chromosome 18 were shown by PCR of several highly polymorphic microsatellites. In this case, application of microFISH was a prerequisite for rapid and precise characterisation of an ESAC. A definite identification of this discontinuous supernumerary marker chromosome would not have been possible using FISH with centromere specific probes or multicolour FISH approaches.     

Minute supernumerary marker chromosomes identified in two patients with a related,larger pseudodicentric chromosome*

We describe two cases in which a minute supernumerary marker chromosome (SMC) was identified in addition to a larger pseudodicentric chromosome. Case 1, a phenotypically normal male, had mosaicism for a psu dic(15;15)(q11.2;q11.2) chromosome and a minute SMC. Fluorescence in situ hybridization (FISH) showed that the minute SMC was D15Z1 positive, indicating a chromosome 15 origin. Case 2 was a 22‐week fetus with mosaicism for a normal and two abnormal cell lines: one had a psu dic (22;22)(q11.2;q11.2) chromosome containing euchromatin, usually associated with cat eye syndrome; the other a minute SMC. The minute SMC was positive with the D14Z1/D22Z1 α‐satellite probe, indicating a chromosome 14 or chromosome 22 origin. Deletion of centromeric material was proposed as one mechanism of centromere inactivation in dicentric chromosomes. The origin of these two minute SMC suggests that they were derived from one of the centromeres of the larger pseudodicentric chromosome. These stable minute SMC may be the by‐product of a deletion event inactivating one centromere of a dicentric chromosome to generate a pseudodicentric chromosome. Alternatively, the minute SMC may originate from further rearrangement of the larger pseudodicentric chromosome. These cases suggest possible mechanisms for the origin of minute SMC. © 2001 Wiley‐Liss, Inc.     

Isodicentric Y chromosome in an Ullrich‐Turner patient without virilization

We report on a 17‐year‐old young woman with Ullrich‐Turner syndrome (UTS), who was found to have a karyotype 45,X/46,X,idic(Y)(q11). She had age‐appropriate genitalia without virilization in spite of the presence of the Y‐derived marker chromosome and SRY locus in 70% of her lymphocytes. Having reviewed the literature, we conclude that a possible explanation for the lack of virilization in these mosaic patients is most likely an uneven distribution of tissue mosaicism (gonadal mosaicism). Am. J. Med. Genet. 91:99–101, 2000. © 2000 Wiley‐Liss, Inc.     

Supernumerary chromosome marker (1) in a developmentally delayed child

A 15-month-old boy with mild developmental delay and several minor anomalies was found to be mosaic 46, XY/47, XY, +mar(l). The marker r(l) was a small de novo ring identified by FISH with a painting type DNA probe. © 1995 Wiley-Liss, Inc.     

Turner syndrome patients with a ring X chromosome

A patient with clinical features of Turner syndrome and a 45,X karyotype in repeated blood cultures was re-evaluated when she spontaneously entered puberty. A ring X cell line was found in a small proportion of fibroblasts. A review of 35 previously published ring X cases is presented. All are mosaic, the major cell line in most cases being 45,X. There is wide variation in the frequency with which the abnormalities associated with Turner syndrome are found in these patients. All have short stature. Some are sexually developed and fertile. Cardiovascular anomalies are uncommon. This phenotypic variation may have at least two causes: the size of the deleted portion at each end of the X chromosome, and the relative frequency and distribution of 45,X and 46,X,r(X) cell lines in various body tissues.     

Segregation of a supernumerary del(15) marker chromosome in sperm

Supernumerary marker chromosomes (SMC) can be associated with both normal and abnormal phenotypes. In addition, SMC are found at higher frequency in males with infertility. We identified a SMC, characterized as a del(15)(q11.2) chromosome, in a phenotypically normal male. Using fluorescence in situ hybridization (FISH), we examined the segregation of the del(15) chromosome in sperm from this patient. Only 6.23% of sperm nuclei showed disomy using a chromosome 15 alpha-satellite FISH probe, instead of the expected 50%. In addition, FISH analysis showed no increase for non-disjunction of chromosome 18, excluding an interchromosomal effect for this chromosome. The significant decrease in sperm bearing the del(15) may be due to tissue-specific mosaicism or a result of some form of selection against the del(15) during spermatogenesis. This finding provides a basis for the observation that SMC(15) are less likely to be inherited from a paternal carrier.     

应用FISH和PCR技术鉴别Turner综合征患者标记染色体起源

目的　为指导遗传咨询,鉴别Turner 综合征患者微小标记染色体起源。方法　选择SRY 基因编码区1 对特异寡核苷酸引物、X 和Y 染色体特异探针,采用PCR 及荧光原位杂交方法,对8 例具有Turner 综合征体征的患者进行标记染色体分析。结果　5 例患者标记染色体起源于X染色体;3 例起源于Y 染色体,其中2 例SRY 基因序列扩增,可见男性特异扩增带,另1 例无男性特异扩增带。结论　FISH 与PCR 技术结合可准确鉴别标记染色体,对选择治疗方案及了解核型与表型关系有指导意义。