47,XX,+der(18),t(9;18)(p24;q21) mat: a distinct partial trisomy 18q--syndrome?

A moderately retarded girl had a 47,XX,+der(18),t(9;18)(p24;q21)mat abnormality that was inherited from her mother, who had a 46,XX,t(9;18)(p24;q21) karyotype in most cells, and a minor cell line of 47,XX,+der(18),-t(9;18)(p24;q21). Her dysmorphic features--bilateral epicanthic folds, low-set, abnormal ears, low posterior hairline, clinodactyly of the 5th fingers, and broad great toes--were similar to those of other patients with an additional number 18 chromosome in which all or most of the long arm was missing, thus raising the possibility of a distinct syndrome.     

一例伴有der(Y)t(Y;1)异常的多发性骨髓瘤的临床和实验研究

目的 对1例伴有不平衡染色体易位der(Y)t(Y;1)的多发性骨髓瘤(multiple myeloma,MM)患者进行细胞遗传学、中期荧光原位杂交、免疫学及临床研究.方法 采用细胞遗传学G显带行中期染色体核型分析;用1号染色体涂抹探针、Y染色体异染色质区探针进行中期荧光原位杂交检测;免疫分型检测CD38、CD138、ZAP70等的表达及免疫电泳检测免疫球蛋白类型等.结果 细胞遗传学分析结果 发现患者具有高度复杂的异常克隆,其核型为:92,XXYY[3]/49,X,der(Y)t(Y;1)(q12;q21),t(11;14)(q13;q32),+18,+20,+21[47]/49,X,idem,del(13q22),ace[1]/98,XX,der(Y)t(Y;1)×2,+18,+18,+20,+20,+21,+21[10]/46,XY[19].中期荧光原位杂交结果 证实der(Y)t(Y;1)的G显带结果 ,为1q部分三体与Y染色体长臂的不平衡易位.其异常的单克隆免疫球蛋白为IgD,定量6.24 g/L;免疫分型结果 为表达CD38、CD138,不表达ZAP70,考虑为异常克隆浆细胞的表达.结论 Y染色体的结构异常在血液系统肿瘤中非常罕见,本文报道1例发生于多发性骨髓瘤中的伴der(Y)t(Y;1)的核型异常、实验室及临床特点.     

Cytogenetic and molecular studies of an X;21 translocation previously diagnosed as complete monosomy 21

We studied a child with apparent monosomy of chromosome 21. Cytogenetic, FISH and microsatellite analyses revealed a 45,X,−21,+der(X)t(X;21)(q25;q21.1) karyotype resulting from a de novo, unbalanced, X;21 non-reciprocal translocation of paternal origin, with partial monosomy of chromosomes 21 and X. An extreme, skewed X-inactivation pattern of the der(X) chromosome was demonstrated. Skewed inactivation probably accounted for a mild phenotype with respect to Xq25 → qter deletion while propagation of inactivation to the adjacent 21q region may account for mild clinical features associated to distal 21q monosomy.     

Familial ring (18) mosaicism in a 23-year-old young adult with 46,XY,r(18) (::p11→q21::)/46,XY karyotype, intellectual disability, motor retardation and single maxillary incisor and in his phenotypically normal mother, karyotype 47,XX,+r(18)(::p11→q21::)/46,XX

We report on a 23-year-old man with craniofacial findings of the holoprosencephaly spectrum disorder (microcephaly, hypotelorism, depressed nasal bridge, single median maxillary central incisor), fusion of C2-C3 vertebrae, intellectual disability, and severe sleep apnea. Chromosome analysis of blood lymphocytes showed 75% ring (18) cells and 25% normal cells, karyotype mos 46,XY,r(18)(::p11→q21::)[75]/46,XY[25]. His mother was phenotypically normal except for a double ureter and bifid renal pelvis as in his son. She had a supernumerary ring (18) in 10% of blood lymphocytes, karyotype mos 47,XX,+r(18)(::p11→q21::)[10]/46,XX[90]. Familial ring (18) is a rare cytogenetic abnormality. This is the first report of a mother with a supernumerary ring (18) and a son with ring (18) mosaicism. Interestingly, the son showed a true mosaicism (mixoploidy) of ring (18) and normal cells. The mother's 46,XX cells could be easily explained by mitotic instability and ring loss during cell division. However, the coexistence of ring (18) and normal cells in the son is unusual. Possibly, during early postzygotic divisions of a 47,XY,+r(18) zygote, two (possibly subsequent) genetic events could have occurred, one when one normal chromosome 18 was lost (resulting in a cell line with ring 18), and one when the ring 18 was lost (resulting in a cell line without ring, "escape to normal"). Alternatively, the zygote of the son could have been 46,XY,r(18), and postzygotic loss of the ring 18 could have resulted in monosomy 18 cells followed by duplication of chromosome 18 in these cells (a rare mechanism for cell survival previously described as "compensatory" isodisomy).     

Cytogenetic and molecular analysis of a ring (21) in a patient with partial trisomy 21 and megakaryocytic leukemia

We describe a patient with an asymmetric double ring 21 in mosaic form, 45,XX,-21/46, XX,-21,+r(21), who has limited manifestations of Down syndrome and who developed acute myelofibrosis and megakaryocytic leukemia (AMKL), FAB M7, a hematologic disorder particularly common in Down syndrome patients. In situ hybridization studies, gene dosage, and DNA polymorphism analysis showed that the ring chromosome carries a duplicated region which extends from D21S406 on the centromeric side and includes marker D21S3 on the telomeric side. FISH studies indicate two sizes of ring 21 in the patient. The origin of the supernumerary chromosome 21 in the proband was paternal; furthermore, the r(21) probably was formed postzygotically. Included in the duplicated segment are the candidate genes for leukemia AML-1, ETS, and ERG. The potential significance of disomic homozygosity of loci on 21q in M7 megakaryocytic leukemia is discussed. © 1995 Wiley-Liss, Inc.     

Meiotic origin of two ring chromosomes 18 in a girl with developmental delay

We report on the cytogenetic, fluorescence in situ hybridization (FISH), and molecular results obtained for a patient with a mild and nonspecific pattern of minor anomalies and developmental delay. In the proband's karyotype one chromosome 18 was replaced by a ring chromosome 18 in all metaphases, with deletion of the terminal regions. Furthermore, 56% of the metaphases contained a supernumerary small ring chromosome. Microdissection followed by FISH analysis demonstrated that the small ring chromosome consisted of material from the pericentromeric region of chromosome 18. The karyotype was defined as 46,XX,r(18)(p11.3q23)[88]/47,XX,r(18)(p11.3q23)+r(18)(p11.22q12.2)[112]. Thus, the patient has a deletion at 18pter and at 18qter, and a mosaic partial trisomy of the pericentromeric region of chromosome 18. We undertook molecular analysis using DNA samples of the patient and her parents in order to clarify the origin and possible mode of formation of the chromosome abnormalities. Our results show a paternal origin of the structurally normal chromosome 18 and a maternal origin for both ring chromosomes 18. Interestingly, the smaller ring chromosome did not arise postzygotically from the larger ring, since the two ring chromosomes contain genetic material derived from the two different maternal chromosomes 18. The abnormalities appear to have arisen during a meiotic division, and it could be speculated that both ring chromosomes 18 arose simultaneously due to complex pairing and recombination events. After fertilization, the small ring chromosome was lost in a subset of cells, thus leading to mosaicism.     

21号环状染色体的细胞遗传学分析

目的通过对1例21号环状染色体嵌合体患者的细胞遗传学分析,探讨21号环状染色体的形成原因,临床表型与染色体区带及嵌合比例的关系。方法应用染色体常规标本、G显带、C显带技术对21号环状染色体进行识别与区带定位。结果患者核型为mos46,XX,r（21）（pllq22）[91]／45,XX,-21[5]／46,XX,dicr（21;21）（pllq22;p11q22）[4]。结论环状染色体断裂位点在21pll和q22,21号环状染色体综合征的临床表现与核型嵌合比例及21q末端缺失的多少相关,女性不孕可能与21q22片段的缺失相关。     

Complex karyotype in a low grade phyllodes tumor of the breast

Cytogenetic analysis of a phyllodes tumor of low grade malignancy disclosed the karyotype 52-55,XX, -1,+5,+7,+9,+10,+11,-15,+18,-19,+20,der(21)t(1;21)(p13;q22),+mar1x 2-4,+mar2[cp18]/46,XX. This study shows that a complex chromosome karyotype can be found in low-grade phyllodes tumors and is not necessarily a sign of extreme malignancy of these neoplasms.     

一例idic(15)来源的嵌合型标记染色体的遗传学分析

目的:应用细胞遗传学和分子生物学检测方法明确1例嵌合型标记染色体患者的核型及其来源。方法:抽取患者的外周血样,进行染色体核型分析、基因芯片检测和荧光原位杂交检测。结果:染色体分析结果显示患者核型为mos 47,XX,+mar [45]/48,XX, +2mar[3]/ 46,XX[52];基因芯片检测结果为arr[hg...     

Precise mapping of a de novo duplication 18(q21→q22) utilizing cytogenetic,biochemical, and molecular techniques

We describe the first de novo inverted duplication of 18q. Due to the difficulty of identifying de novo chromosome abnormalities based solely on cytologic studies, precise definition of the 18q duplication was attempted by integrating cytogenetic and clinical findings with biochemical and molecular dosage studies. The combined results demonstrated that the proposita had a duplication of 18q21→q22 with a karyotype of 46,XX,–18,+inv dup(18) (pter→q12.1::q22→q21::q12.1→qter). The duplication of this specific chromosome region does not result in the typical 18 phenotype, supporting the hypothesis that various loci on chromosome 18 may interact to produce the manifestations of this syndrome. © 1993 Wiley-Liss, Inc.     

Marker chromosome 21 identified by microdissection and FISH

A child without Down syndrome but with developmental delay, short stature, and autistic behavior was found to be mosaic 46,XX/47,XX,+mar(21) de novo. The marker was a small ring or dot-like chromosome. Microdissection of the marker was performed. The dissected fragments were biotinylated with sequence-independent PCR as a probe pool for fluorescence in situ hybridization (FISH). FISH results suggested an acrocentric origin of the marker. Subsequent FISH with α-satellite DNA probes for acrocentric chromosomes, and chromosome-specific 21 and 22 painting probes confirmed its origin from chromosome 21. © 1995 Wiley-Liss, Inc.     

Structural abnormalities of chromosome 8 and fetoplacental discrepancy: A second case report and review of fetal phenotype of 8p inverted duplication deletion syndrome

We described a new second case of fetoplacental discrepancy involving first trimester prenatal detection of mosaic isochromosome i (8) (q10). A 32-year-old woman underwent chorionic villous sampling because of increased fetal nuchal translucency. Analysis of direct chromosome preparations was performed by R-banding and FISH using subtelomeric, centromeric and whole chromosome painting probes for chromosome 8 showing the presence of an isochromosome 8q with a complex, female mosaic karyotype: mos 46,XX,i (8) (q10)[13]/46,XX,del (8) (p23)[10]. Cytogenetic analysis of cultured CVS showed an interstitial duplication with concomitant terminal deletion of the short arm of chromosome 8: 46,XX,der (8)del (8) (p23)dup (8) (p?)[18]. Array-CGH analysis from cultured trophoblasts and fetal tissues revealed a 6.69 Mb terminal deletion in 8p23.3p23.1 associated with a 31.49 Mb duplication in 8p23.1p11.1. FISH analysis confirmed the 8p inverted duplication deletion syndrome. Moreover, polymorphic DNA marker analysis demonstrated that the derivative chromosome 8 was of maternal origin. FISH analysis of cultured peripheral blood lymphocytes showed that the mother also carried a cryptic paracentric inversion inv (8) (p23). Our report contributes to expand the fetal phenotype of 8p inverted duplication deletion syndrome and also provides further insight into the underlying mechanism of this rare genomic disorder.     

Case report of de novo dup(18p)/del(18q) and r(18) mosaicism

This is a report of a 27-year-old woman with an unusual de novo chromosomal abnormality. Mosaicism was identified in peripheral blood cells examined by standard G-bands by trypsin using Giemsa (GTG) analysis and fluorescence in situ hybridization (FISH) analysis with chromosome-18 region-specific probes, 46,XX,del(18)(pter → q21.33:)[41], 46,XX,r(18)(::p11.21 → q21.33::)[8], and 46,XX,der(18)(pter → q21.33::p11.21 → pter)[1]. On the other hand, the karyotype of periodontal ligament fibroblasts was nonmosaic, 46,XX, der(18)(pter → q21.33::p11.21 → pter)[50]. All cell lines appeared to be missing a portion of 18q (q21.33 → qter). The pattern of the dup(18p)/del(18q) in the rod configuration raises the possibility of an inversion in chromosome 18 in one of the parents. However, no chromosomal anomaly was detected in either parent. The most probable explanation is that de novo rod and ring configurations arose simultaneously from an intrachromosomal exchange. The unique phenotype of this patient, which included primary hypothyroidism and primary hypogonadism, is discussed in relation to her karyotype.     

Characterization of a de novo 48,XX, + r(X), + r(17) by in situ hybridizatio in a patient with neurofibromatosis (NF1)

We describe a patient with familial neurofibromatosis (NF1), short stature, developmental delay, and a de novo chromosome abnormality. In sity hybridization was done using chromosome specific centromere probes to characterize the karyotype as 46,XX/47, XX,+r(X) (p11q11)/47,XX,+r(17) (p11q11)/48, XX,+r(X) (p11q11),+r(17) (p11q11). The NF1 mutation, as well as each superunmerary ring chromosome, may have played a role in perturbing the normal developmenal process of this patient. © 1993 Wiley-Liss, Inc.     

Hypoplastic left heart in a female infant with partial trisomy 4q due to de novo 4;21 translocation

We present a female infant with mild dysmorphic features and congenital heart defect: hypoplastic left heart with aortic atresia and hypoplastic aortic arch, ventricular septal defect, and a nonrestrictive atrial communication. Chromosome analysis showed an unbalanced translocation that contained additional material from 4q translocated onto 21q. This resulted in partial trisomy 4 and monosomy for the 21q telomeric region. The derivative chromosome was characterized using G-banding, M-FISH, and whole chromosome painting. The karyotype was described as 46,XX,der(21)t(4;21)(q25;q22.3).ish(wcp4+;wcp21+). Additional analyses with FISH probes specific for 21q 22.3, 21q22.2, 21q21.1, and 21q11.2 did not indicate any chromosome 21 duplication within the derivative chromosome 21. Monosomy for the telomeric portion of 21q was demonstrated using a tel 21q probe (Oncor). The patient underwent stage 1 Norwood procedure to manage her heart defect. Poor feeding and failure to thrive complicated the postsurgical period. The child subsequently underwent funduplication and feeding tube placement, and at 4.5 months of age presented with microcephaly and developmental delay. Hypoplastic left heart was previously reported with increased frequency in relatively common numeric chromosomal aberrations, such as monosomy X, trisomies 21, 18, and 13, and in various structural chromosomal defects. Our report presents new evidence for the co-occurrence of hypoplastic left heart with a duplicated portion of chromosome 4 distal to 4q25. In addition, monosomy for the telomeric region of chromosome 21 may have implications in the phenotype.     

Partial trisomy 18 in a family with a translocation (18;21)(q21;q22).

A family is described in which 2 sibs had similar congenital abnormalities. Chromosome investigation of the mother and another child disclosed they were carriers of a translocation t(18;21)(q21;q22). The karyotype of one of the abnormal infants was determined and was found to be consistent with partial trisomy 18,46,XY,-21,+der (21),t(18;21) ((18pter leads to 18q21::21q22 leads to 2 lqter)mat.     

Ring chromosome 21 in phenotypically apparently normal persons: report of two families from Switzerland and Italy

If a ring 21, originating from breaks close to the telomere of 21q and anywhere in 21p, replaces a normal 21, it may be associated with an apparently normal phenotype. An apparently normal mother and son were ascertained by a prenatal chromosome study. A second mother, with a ring 21 but without gross anomalies, is short of stature, has epilepsy and has a low normal intelligence. He daughter is a mosaic: 46,XX/47,XX,+r(21) and has the Down's syndrome. None of these four persons was found to have mitoses with more than one ring 21 or with rings of double size.     

Transmission of a ring chromosome 18 from a mother with 46,XX/47,XX, + r(18) mosaicism to her daughter, resulting in a 46,XX,r(18) karyotype.

A 6 month old patient is reported with a ring chromosome 18 confirmed by cytogenetic studies and in situ hybridisation. Her clinical features were similar to previous cases of ring chromosome 18 syndrome. The ring chromosome was inherited from the phenotypically and mentally normal mother with a mos 46,XX/47,XX, + r(18) karyotype.     

Clinical and molecular‐cytogenetic studies in seven patients with ring chromosome 18

We report the results of detailed clinical and molecular‐cytogenetic studies in seven patients with ring chromosome 18. Classical cytogenetics and fluorescence in situ hybridization (FISH) analysis with the chromosome 18 painting probe identified five non‐mosaic and two complex mosaic 46,XX,dup(18)(p11.2)/47,XX,dup(18)(p11.2),+r(18) and 46,XX,dup(18)(p11.32)/47,XX,dup(18)(p11.32),+r(18) cases. FISH analysis was performed for precise characterization of the chromosome 18 breakpoints using chromosome 18–specific short‐arm paint, centromeric, subtelomeric, and a panel of fifteen Alu‐ and DOP‐PCR YAC probes. The breakpoints were assessed with an average resolution of ∼2.2 Mb. In all r(18) chromosomes, the 18q terminal deletions ranging from 18q21.2 to 18q22.3 (∼35 and 9 Mb, respectively) were found, whereas only in four cases could the loss of 18p material be demonstrated. In two cases the dup(18) chromosomes were identified as inv dup(18)(qter→p11.32::q21.3→qter) and inv dup(18)(qter→p11.32::p11.32→p11.1: :q21.3→qter)pat, with no evidence of an 18p deletion. A novel inter‐intrachromatid mechanism of formation of duplications and ring chromosomes is proposed. Although the effect of “ring instability syndrome” cannot be excluded, the phenotypes of our patients with characteristic features of 18q‐ and 18p‐ syndromes are compared and correlated with the analyzed genotypes. It has been observed that a short neck with absence of cardiac anomalies may be related to the deletion of the 18p material from the r(18) chromosome. © 2001 Wiley‐Liss, Inc.     

Complex karyotypic anomalies in a bizarre leiomyoma of the uterus

Cytogenetic investigation of short-term cultures from a bizarre leiomyoma of the uterus, a tumor type not hitherto karyotypically characterized, revealed two abnormal clones with multiple complex rearrangements. Three-fourths of the aberrant cells were hypodiploid with the composite karyotype 38–44, XX,?6,?7,?10,?11,+20,?22, r(1), der(2) (:2p23→cen→2q13::1q21→1qter), der(2)t(2;9)(p21;q13), t(5;?)(q35;?), t(5;?),(q35;?), + der(5)t(5;15)(q11;q15), der(8)t(8;11)(q24;q13), t(15;?)(p12;?), der(16)t(12;16)(q13;p13),+r,+mar. The remaining abnormal mitoses were hypotetraploid, with chromosome numbers ranging from 74 to 86. These massively rearranged cells showed the same markers that were found in the hypodiploid clone, but in duplicate, indicating that this clone had arisen through polyploidization of hypodiploid cells. Flow cytometry revealed a DNA index of 1.03.