Translocation (15;17) and trisomy 21 in the microgranular variant of acute promyelocytic leukemia.

Cytogenetic abnormalities in acute myelogenous leukemia have been identified as one of the most important prognostic factors. Favorable chromosomal changes such as inv(16), t(8;21), and t(15;17) are associated with higher rates of complete remission and event-free survival. Translocation t(15;17) characterizes acute promyelocytic leukemia (APL) (French-American-British [FAB] class M3) in almost all patients. Secondary chromosomal abnormalities are also present in approximately one-third of patients with newly diagnosed APL. We present a 26-year-old Hispanic man diagnosed with the microgranular variant of APL (FAB class M3v) whose initial cytogenetics included t(15;17) and trisomy 21. The prognostic implications of trisomy 21 and other secondary cytogenetic aberrations in APL are reviewed. To our knowledge, this is the first reported case of trisomy 21 with t(15;17) in the microgranular variant of APL.     

t(15;21)(q15;q22.1)pat resulting in partial trisomy and partial monosomy of chromosomes 15 and 21 in two offspring

Two sibs, carriers of unbalanced products of the translocation t(15;21)(q15;q22.1)pat, are described. The sister had Prader-Willi syndrome due to deletion 15 (pter > q15) and partial trisomy 21 (pter > q22.1); her brother had partial trisomy 15 (pter > q15) and partial monosomy 21 (pter > q22.1). The translocation breakpoint on chromosome 21 was located proximal to the SOD1 gene, within a region of 4.0 cM (2.3 Mb) between the loci D21S217 and D21S213. The correlations between the clinical presentation and the molecular findings of the two sibs are discussed in relation to other patients with partial trisomy and monosomy 21. © 1996 Wiley-Liss, Inc.     

Non-reciprocal translocation (5;15), isodicentric (15) and Prader-Willi syndrome

A non-reciprocal translocation (5;15) and an isodicentric (15) resulting in trisomy 15pter----15q1?3 and monosomy 5qter [46,XY,-5,-15,+der(5)t(5;15) (5pter----5q35::15q13----15qter),+idic(15) (pter----q1?3::q1?3----pter)] was found in a 28-year-old profoundly retarded male resident of a state institution. Early developmental history and childhood and adult physical findings resembled those of Prader-Willi syndrome (PWS) patients. The parents' unbanded chromosomes were normal. Blood groups of parents and propositus were uninformative with regard to identifying gene deletions or duplications.     

Translocation (Y;1)(q12;q21) in acute leukemia

This report documents one patient with myelodysplasia evolving into acute leukemia who showed a t(Y;1) translocation confirmed by in situ hybridization. Most of the q arm of the Y chromosome was translocated to an additional q arm of chromosome 1, resulting in trisomy 1q. To our knowledge only four other cases with this t(Y;1) have been reported.     

Chronic myelomonocytic leukemia with trisomy 8 and a related clone with trisomy 8 and t(15;17)

We describe a patient with chronic myelomonocytic leukemia who showed trisomy 8 in 100% of his bone marrow metaphases. Of interest was the finding that 20% of the Giemsa-banded metaphases also showed t(15;17)(q22;q21), with breakpoints indistinguishable from those seen in cases of acute progranulocytic leukemia (APL). The patient showed no morphologic or clinical evidence of APL, and he died after 6 months, with no evidence that the disease had progressed to acute leukemia. Although cytogenetically the breakpoints appeared to be the same as those in APL, we suspect that this patient's translocation may have differed at the molecular level from the t(15;17) commonly seen in APL.     

Mild craniosynostosis with 1p36.3 trisomy and 1p36.3 deletion syndrome caused by familial translocation t(Y;1)

We report on a 20-year-old man and a 16-year-old woman with a chromosomal imbalance derived from a balanced translocation, t(Y;1)(q12;p36.3) of the father. The man had a partial trisomy for 1p36.3-pter [46,X,der(Y)t(Y:1)(q12;p36.3)] and mild craniosynostosis of metopic and sagittal sutures as well as a borderline mental impairment, while the woman with a deletion for 1p36.3-pter [46,XX,der(1)t(Y;1)(q12;p36.3)] showed dysmorphic face with large anterior fontanel and severe developmental delay. Fluorescence in situ hybridization (FISH) showed that his trisomy spanned the 5.3-Mb region from 1p telomere harboring the critical region for craniosynostosis. To our knowledge, the man is the first case of a pure type of simple 1p36.3 trisomy as the effect of heterochromatic Yq12-qter deletion likely does not affect phenotype.     

Inherited partial trisomy #15 complicated by neuroblastoma

The proband in this study had multiple congenital malformations and a constitutional 46,XY,-13, + der(13),t(13;15)(q34;q23)mat chromosome complement. A bone marrow aspirate revealed neuroblastoma, and cytogenetic studies on tumor cells revealed, in addition to the partial trisomy #15 and probable partial monosomy #13, hypotetraploidy with a mean chromosome number of 82-84, including 3 or 4 copies of each autosome, 2 X chromosomes, no Y chromosome, and a marker. Translocations involving chromosomes #1, #2, #3, #7, and #14 were present, along with multiple double minutes. The possibility that the inherited partial trisomy #15 (and/or partial chromosome #13 monosomy) predisposed to neuroblastoma and additional chromosome changes in this tumor is discussed.     

Trisomy 14 mosaicism with t(14;15)(q11;p11) in offspring of a balanced translocation carrier mother

A 2-year-old girl with growth and developmental retardation, minor facial anomalies, asymmetry of face and body, tetralogy of Fallot, and reticular hyperpigmentation of the skin was found to have mosaic trisomy 14 involving a t(14;15)(q11;p11). The patient showed mosaicism for 46,XX cell line, apparently resulting from a break of the translocation chromosome and a subsequent loss of 14q. The mother has a balanced translocation t(14;15)(q11;p11). Inherited trisomy 14 has not been reported previously.     

<Emphasis Type="Italic">RABGAP1L</Emphasis> gene rearrangement resulting from a der(Y)t(Y;1)(q12;q25) in acute myeloid leukemia arising in a child with Klinefelter syndrome

In this study, we report the molecular cytogenetic characterization of an acute myeloid leukemia with a der(Y)t(Y;1)(q12;q25) in bone marrow cells in a child with Klinefelter syndrome. Conventional cytogenetics demonstrated the unbalanced translocation, i.e., a trisomic 1q25-qter juxtaposed to Yq12 replaced the terminal segment of chromosome Y was acquired and present only on bone marrow cells. Fluorescence in situ hybridization showed that the breakpoint at 1q25 disrupted RABGAP1L, a strongly expressed gene in CFU-GEMM, erythroid cells, and megakaryocytes, while the Yq12 breakpoint fell within the heterochromatic region. As der(Y)t(Y;1)(q12;q25) was an isolated cytogenetic change, RABGAP1L rearrangement as well as gene(s) dosage effects correlated to 1q25-qter trisomy, and Yq12-qter loss may make a major contribution to leukemogenesis and/or disease progression. Maria Cristina Roberti and Roberta La Starza should be regarded as joint first authors.     

Deletion of chromosome 15pter→q11.2 due to t(Y;15) in a boy with Prader-Willi syndrome

Chromosome analysis of lymphocytes from a patient with the clinical presentation of Prader-Willi syndrome showed the presence of 45 chromosomes, including a der(Y) resulting from an unbalanced t(Y;15)(q12;q11.2). In situ hybridization using DYZ3 and DYZ2 showed positive signals at the paracen-tromeric region on the short arm and at the heterochromatic region of the long arm of the Y chromosome, respectively. The Prader-Willi syndrome in this patient is caused by the deficiency of a very small region involving 15cen→q11.2.     

An identical t(Y;1)(q12;q21) in two patients with myelodysplastic syndromes

Two male patients with myelodysplastic syndromes, one with refractory anemia with excess blasts (RAEB), the other with chronic myelomonocytic leukemia both had in their bone marrow and peripheral blood cells the same abnormal karyotype 46,X,-Y, + der (Y)t(Y;1)(q12;q21). This abnormality produced trisomy for the 1q21-1qter region of chromosome 1. In addition to the t(Y;1), the patient with RAEB had a del(20)(q11) abnormality in separate CFU-GM and BFUe progenitor cell populations. The t(Y;1) clone of this patient underwent chromosomal evolution with the acquisition of trisomies for chromosomes 2, 6, 8, and 9. Cytogenetic analysis of serial peripheral blood samples showed that the t(Y;1) clone and its derivatives gradually replaced that with the 20q- abnormality. Metaphase cells trisomic for chromosomes 2, 6, 8, and 9 were found predominantly in the CFU-GM population and only rarely in BFUe colonies, suggesting that chromosomal evolution was largely confined to the granulocytic lineage.     

Deletion of chromosome 15pter-->q11.2 due to t(Y;15) in a boy with Prader-Willi syndrome.

Chromosome analysis of lymphocytes from a patient with the clinical presentation of Prader-Willi syndrome showed the presence of 45 chromosomes, including a der(Y) resulting from an unbalanced t(Y;15)(q12;q11.2). In situ hybridization using DYZ3 and DYZ2 showed positive signals at the paracentromeric region on the short arm and at the heterochromatic region of the long arm of the Y chromosome, respectively. The Prader-Willi syndrome in this patient is caused by the deficiency of a very small region involving 15cen-->q11.2.     

Uneven frequencies of secondary chromosomal abnormalities in acute myeloid leukemias with t(8;21), t(15;17), and inv(16)

The types and incidences of secondary chromosomal abnormalities were analyzed in three subtypes of leukemia with recurrent abnormalities, translocations t(8;21), t(15;17), and inversion inv(16). The main types of clonal secondary abnormalities were similar to those described in the literature, loss of sex chromosome associated with t(8;21), trisomy 8 with t(15;17), and trisomies 8 or 22 with inv(16). On the whole, the incidence of clonal abnormalities was significantly higher in t(8;21) leukemia than in the two other subtypes. This difference was not related to a chromosomal instability peculiar to this leukemia subtype, because the incidence of nonclonal abnormalities was the same in the three types of leukemia studied. The significance of secondary clonal abnormalities remains speculative. A careful comparative analysis of structural rearrangements of the chromosomes usually involved in secondary abnormalities must be carried out as a first step to identify the key genes altered.     

Frequency of trisomy 15 and loss of the Y chromosome in adult leukemia.

In the interpretation of the varied and complex cytogenetic counts obtained in analysis of bone marrow (BM) samples for leukemia, loss or gain of certain chromosomes may or may not be significant for prognosis. Loss of the Y chromosome in elderly males is a benign finding. Trisomy 15 is rare and may represent another age-related abnormality, particularly in males, together with -Y. We reviewed 3,242 routine referrals sent to our laboratory for BM cytogenetics, over a period of 34 months. We detected 5 cases with uncomplicated trisomy 15, 3 in males and 2 in females. Three of these patients had the diagnosis of myelodysplastic syndrome (MDS). All 3 males showed a -Y cell line, although the 2 females did not have an X chromosome loss. All 5 patients were alive and well at times varying from 12 months to 4 years post-diagnosis. In the further analysis of our referral cohort, there were 62 males with loss of the Y chromosome as the sole abnormality, and of these 47 (76%), were referred with myeloid disease. The frequency of trisomy 15 in our laboratory was 1/475 referrals, but 1/292 in successful cultures from new patients. This is the first report providing frequency data for trisomy 15. Further data with longer term follow-up is required to establish the significance of trisomy 15 in elderly leukemic patients.     

A case of 47,XY,+der(15),t(3;15) (p25;qll)pat presenting as partial 3p trisomy syndrome with multiple joint contractures

Partial 3p trisomy is a rare chromosomal syndrome which results in a characteristic phenotype. We present a case of partial 3;15 trisomy with clinical features of partial 3p trisomy syndrome and multiple joint contractures.     

Trisomy 15 is frequently observed as a minor clone in patients with Anemia/MDS/NHL and as a major clone in patients with AML

Trisomy 15 as the sole karyotypic aberration is an uncommon clonal cytogenetic aberration in hematological malignancies, making its significance unclear. Previous studies have reported relations of trisomy 15 with low-grade myelodysplasia or a benign age-related phenomenon associated with loss of the Y chromosome. To define the significance of trisomy 15, we conducted a retrospective study of all examples of trisomy 15 accessed in our laboratories. Trisomy 15 was observed as a clonal abnormality (> or =2 cells) in 17 cases and nonclonal (single cell) in 9 cases. The majority of cases (14/17 clonal cases) had a minor clone (5-35% of metaphase cells) of trisomy 15. The minority of cases (3/17) had a major clone (80-95% of metaphase cells) of trisomy 15. Two of these 3 cases were diagnosed as having acute myelocytic leukemia. Fluorescence in-situ hybridization (FISH) with the use of a chromosome 15-specific alpha-satellite probe was performed on 3 of 17 clonal cases and on 3 of 9 nonclonal cases. FISH results revealed the presence of a minor clone (from 3 to 5 of 700 interphase cells) in 5 of them, 2 of which had trisomy 15 in 20% of metaphase cells. These results may indicate that the 20% of trisomy 15 are very likely an overrepresentation of a very minor clone that could be transitory. In summary, the analysis of our cytogenetic and FISH results revealed the presence of two types of trisomy 15 clones: a minor clone that could be transitory or indolent and a major clone that could be of a neoplastic nature.     

Minimal phenotype in a girl with trisomy 15q due to t(X;15)(q22.3;q11.2) translocation

Few cases of de novo unbalanced X;autosome translocations associated with a normal or mild dysmorphic phenotype have been described. We report a 3-year-old dizygotic female twin with prenatally ascertained increased nuchal translucency. Prenatal chromosome studies revealed nearly complete trisomy 15 due to a de novo unbalanced translocation t(X;15)(q22;q11.2) confirmed postnatally. A mild phenotype was observed with normal birth measurements, minor facial dysmorphic features (hypertelorism, short broad nose, and a relatively long philtrum), and moderate developmental delay at the age of 3 years in comparison to her male fraternal twin. Replication timing utilizing BrdU and acridine-orange staining showed that the der(X) chromosome was late-replicating with variable spreading of inactivation into the translocated 15q segment. The der(X) was determined to be of paternal origin by analyses of polymorphic markers and CGG-repeat at FMR1. Methylation analysis at the SNRPN locus and analysis of microsatellites on 15q revealed paternal isodisomy with double dosage for all markers and the unmethylated SNRPN gene. The Xq breakpoint was mapped within two overlapping BAC clones RP11-575K24 and RP13-483F6 at Xq22.3 and the 15q breakpoint to 15q11.2, within overlapping clones RP11-509A17 and RP11-382A4 that are all significantly enriched for LINE-1 elements (36.6%, 43.0%, 26.6%, 22.0%, respectively). We speculate that the attenuated phenotype may be due to inactivation spreading into 15q, potentially facilitated by the enrichment of LINE-1 elements at the breakpoints. In silico analysis of breakpoint regions revealed the presence of highly identical low-copy repeats (LCRs) at both breakpoints, potentially involved in generating the translocation.     

一例急性早幼粒细胞白血病同时伴有ins(15;17),t(2;17;20)和三体8异常

目的 对1例伴有ins(15;17),t(2;17;20),+8复杂异常的急性早幼粒细胞白血病(acute promyelocytie leukemia,APE)病例进行细胞和分子遗传学研究.方法 按常规制备染色体,以R显带技术进行核型分析,并先后作多色荧光原位杂交(multiplex fluoresence in situ hybridization,M-FISH)、染色体涂染和PML-RARa双色FISH检测.结果 R显带核型分析为47,XY,2q-,+8,17q+,20p+;M-FISH检测为:47,XY,t(2;17;20)(q24;q21;p13),+8;染色体涂染证实了2qZ4以下片段易位到17q21上和17q21以下片段易位到20p13上;双色FISH示17号染色体上RARa(retinoic acid receptora,RARe)基因部分片段插入到15号染色体形成PNL-RARa融合基因,即ins(15;17)(q22;q21.1q21.3).结论 FISH技术是明确隐匿/插入易位的可靠手段,凡形态学拟诊为APL而常规核型分析未发现t(15;17)者均应进行FISH检测.     

Partial trisomy of chromosome 10(q22-q24) due to maternal insertional translocation (15;10)

Interchromosomal insertional translocations are rare chromosome rearrangements with an incidence of about 1:80,000 live births. We report on the clinical and cytogenetic findings of a newborn baby with partial trisomy 10q22-10q24 due to a maternal insertional translocation 15;10. Partial trisomy of the long arm of chromosome 10 is a distinctive chromosome aberration characterized by prenatal-onset growth retardation and craniofacial, skeletal, and other somatic anomalies. Most cases are unbalanced products from reciprocal chromosome translocations, and insertional translocations are rarely involved. The proband was initially referred because of severe intrauterine growth retardation, and fluorescence in situ hybridization (FISH) using painting probes confirmed the maternal balanced (15;10) insertion.     

Unique mosaicism in Prader-Labhart-Willi syndrome—a contiguous gene or aneuploidy syndrome?

A 16-year-old boy with Prader-Labhart-Wi11i syndrome (PLWS) had hypotonia, feeding difficulties, failure to thrive, strabismus and bilateral inguinal hernias with cryptorchidism during infancy followed by hyperphagia, marked early-onset obesity with insulin-dependent diabetes mellitus and necrobiosis lipoidica diabeticorum, short stature, hypogonadotropic hypogonadism and some of the facial characteristics of the individuals with the PLWS. IQ is estimated around 90. Cytogenetic studies showed mosaicism: 45,X, t(Y;15) with partial deletion 15 (15pter → 15ql2); 46,X, t(Y;15), dic(15)(15pter → 15ql2::15ql2 → 15pter) and 47,X,t(Y;15), dic(15), dic(15). The dic(15) was bisatel1ited, NOR-positive on both arms and represented inv dup(15). Thus, the 2 lines with the dic(15) showed partial trisomy 15 (15pter → 15q 12) and partial pentasomy 15 (15pter → 15ql2), respectively. The cell line ratios were different in lymphocyte and fibroblast cultures. The unique cytogenetic findings in this patient, the reports of a variety of chromosome 15 aberrations in PLWS; as well as aberrations of other chromosomes, suggest that the condition is a contiguous gene syndrome rather than an aneuploidy syndrome.