Recurrent neural tube defects associated with partial trisomy 2p22-pter: report of two siblings and review of the literature

We report on two male siblings with partial trisomy 2p22-pter and partial monosomy 15q26-qter resulting from a maternally derived translocation t(2;15)(p22;q26). Both fetuses had different neural tube defects (craniorachischisis in the first fetus and anencephaly in the second fetus) which were detected by sonographic examination at the end of the first trimester of pregnancy. This report demonstrates the importance of chromosomal analysis in the etiologic exploration of neural tube defects and supports the importance of 2p24 triplication in neural tube development.     

Molecular mapping of the Edwards syndrome phenotype to two noncontiguous regions on chromosome 18.

In an effort to identify regions on chromosome 18 that may be critical in the appearance of the Edwards syndrome phenotype, we have analyzed six patients with partial duplication of chromosome 18. Four of the patients have duplications involving the distal half of 18q (18q21.1-qter) and are very mildly affected. The remaining two patients have most of 18q (18q12.1-qter) duplicated, are severely affected, and have been diagnosed with Edwards syndrome. We have employed FISH, using DNA probes from a chromosome 18-specific library, for the precise determination of the duplicated material in each of these patients. The clinical features and the extent of the chromosomal duplication in these patients were compared with four previously reported partial trisomy 18 patients, to identify regions of chromosome 18 that may be responsible for certain clinical features of trisomy 18. The comparative analysis confirmed that there is no single region on 18q that is sufficient to produce the trisomy 18 phenotype and identified two regions on 18q that may work in conjunction to produce the Edwards syndrome phenotype. In addition, correlative analysis indicates that duplication of 18q12.3-q22.1 may be associated with more severe mental retardation in trisomy 18 individuals.     

Jumping translocation of 15q24-qter resulting in partial trisomy: a case report

We report on a jumping translocation with five different cell lines detected in four tissues in a 2-year-old patient. This rare type of chromosomal abnormality (not more than 30 cases published so far) proved to be a series of non-reciprocal translocations of the 15q24-qter donor chromosome segment to the telomeric region of chromosomes 5q, 10q, 16q and 19p, respectively. The process, in addition to a few cells without translocation, resulted in partial trisomy of 15q24-qter which was associated with somatic overdevelopment in the patient, with hemihypertrophy and minor anomalies. The phenotype of our patient was different from that of the other two patients found in the literature having the same donor chromosome segment involved in a similar rearrangement. Possibly, the difference in the phenotype lies in the various ratios of somatic mosaicism with five cell lines, in particular the presence of normal one which is extremely rare in patients with jumping translocation. Here we discuss the various ways on how the rearrangement could arise.     

Pericentric inversion with partial 7(q35-->qter) duplication and 7pter deletion: diagnosis by cytogenetic and fish analysis in a 29-year-old male patient

We report on a 29-year-old male patient with an inverted 7(q35-qter) duplication diagnosed by combining cytogenetic and FISH studies. Traditional G-banding detected an abnormally long chromosome 7 which was further demonstrated to be entirely of chromosome 7 origin by using fluorescent whole chromosome 7 painting. The presence within the additional segment of a signal for 7q36 region (Williams control probe) and the absence of signals for 7q33 (Y938G5 probe) and 7q34 (Y815G5 probe) regions indicated that the breakpoint for this rearrangement was distal to 7q34 and proximal to 7q36. A distal 7p22 deletion was confirmed by the absence of signal for the 7p subtelomeric probe. Apart from kyphosis, developmental/mental retardation and abnormal ears, the clinical features of the present patient, who is the oldest individual ever reported with this duplication/deletion, were not typical for partial 7q trisomy syndrome. A review of the cases reported with 7(q35-qter) duplication is made and shows important clinical variability but constantly normal pre- and postnatal growth, a feature which can therefore be confirmed as distinctive of distal 7q trisomy syndrome.     

Comparative genomic hybridization reveals a partial de novo trisomy 6q23-qter in an infant with congenital malformations: delineation of the phenotype

We report the use of comparative genomic hybridization (CGH) to define the origin of a small extra segment (unidentifiable by classical cytogenetics) present in a de novo add(13)q34 chromosome that we found in the karyotype of a newly born boy with congenital heart defects, brain anomalies and dysmorphic signs. Initial investigation with fluorescence in situ hybridization (FISH) and a chromosome-13-specific library revealed that the excess material was not derived from chromosome 13. To uncover the origin of the unknown chromosome material, CGH was carried out on DNA isolated from blood lymphocytes of the patient. By using a conventional fluorescence microscope with no digital imaging devices, a single distinct region with gain of fluorescent intensity was observed on distal chromosome 6q. Confirmation of this finding by FISH with a chromosome-6-specific paint and a subtelomeric yeast artificial chromosome clone from 6q26-q27, in combination with the band morphology of the small extra chromosomal segment, allowed us to diagnose the additional material as being derived from chromosome 6q23-qter. FISH with a telomere 13q probe detected a terminal deletion of 13q34-qter on the derivative chromosome 13, indicating that the der(13) was a result of a translocation event. Genotyping of the hypervariable apolipoprotein (a) gene, which lies within 6q26-q27, showed that the additional chromosome 6 material was inherited from the mother. The karyotype of the proposita is therefore: 46,XY,-13,+der(13)t(6;13)(q23;q34) de novo (mat). Our results confirm the usefulness of CGH as an attractive alternative method for the characterization of constitutional small genetic imbalances and contribute to the delineation of the trisomy 6q23-qter phenotype. Received: 26 November 1996 / Revised: 2 January 1997     

Maternal balanced translocation (4;21) leading to an offspring with partial duplication of 4q and 21q without phenotypic manifestations of Down syndrome

We describe an 8-years old female with supernumerary chromosome der(21)t(4;21)(q25;q22) resulting in partial trisomy 4q25-qter and partial trisomy 21(pter-q22). The extra material was originated from a reciprocal balanced translocation carrier mother (4q;21q). Karyotyping was confirmed by FISH using whole chromosome painting probes for 4 and 21q and using 21q22.13-q22.2 specific probe to rule out trisomy of Down syndrome critical region. Phenotypic and cytogenetic findings were compared with previously published cases of partial trisomy 4q and 21q. Our patient had the major criteria of distal trisomy 4q namely severe psychomotor retardation, growth retardation, microcephaly, hearing impairment, specific facies (broad nasal root, hypertelorism, ptosis, narrow palpebral fissures, long eye lashes, long philtrum, carp like mouth and malformed ears) and thumbs and minor feet anomalies. In spite of detection of most of the 3 copies of chromosome 21, specific features of Down syndrome (DS) were lacked in this patient, except for notable bilateral symmetrical calcification of basal ganglia. This report represents further delineation of the phenotype-genotype correlation of trisomy 4q syndrome. It also supports that DS phenotype is closely linked to 21q22. Nevertheless, presence of basal ganglia calcification in this patient may point out to a more proximal region contributing in its development in DS, or that genes outside the critical region may influence or control manifestations of DS features.     

Further clinical delineation in trisomy 1q32 syndrome.

A male newborn with multiple congenital abnormalities was studied. Clinically, he showed prominent forehead, facial dysmorphism, ear malformations, congenital heart defect and limb anomalies. The cytogenetic studies demonstrated a karyotype 46,XY, der(18) t(1;18)(q32;p11.3)pat with partial trisomy 1q32-qter and a monosomy 18p. The patient displayed clinical features of trisomy 1q but not of monosomy 18p. There are around 80 reports of trisomy 1q32. The purpose of this paper is to describe the first case of a translocation involving 1q and 18p chromosome breakpoints. Additional findings detected in the propositus permit us a further delineation of the trisomy 1q syndrome.     

Spatial and temporal evolution of distal 10q deletion,a prognostically unfavorable event in diffuse low-grade gliomas

Background

The disease course of patients with diffuse low-grade glioma is notoriously unpredictable. Temporal and spatially distinct samples may provide insight into the evolution of clinically relevant copy number aberrations (CNAs). The purpose of this study is to identify CNAs that are indicative of aggressive tumor behavior and can thereby complement the prognostically favorable 1p/19q co-deletion.

Results

Genome-wide, 50 base pair single-end sequencing was performed to detect CNAs in a clinically well-characterized cohort of 98 formalin-fixed paraffin-embedded low-grade gliomas. CNAs are correlated with overall survival as an endpoint. Seventy-five additional samples from spatially distinct regions and paired recurrent tumors of the discovery cohort were analyzed to interrogate the intratumoral heterogeneity and spatial evolution. Loss of 10q25.2-qter is a frequent subclonal event and significantly correlates with an unfavorable prognosis. A significant correlation is furthermore observed in a validation set of 126 and confirmation set of 184 patients. Loss of 10q25.2-qter arises in a longitudinal manner in paired recurrent tumor specimens, whereas the prognostically favorable 1p/19q co-deletion is the only CNA that is stable across spatial regions and recurrent tumors.

Conclusions

CNAs in low-grade gliomas display extensive intratumoral heterogeneity. Distal loss of 10q is a late onset event and a marker for reduced overall survival in low-grade glioma patients. Intratumoral heterogeneity and higher frequencies of distal 10q loss in recurrences suggest this event is involved in outgrowth to the recurrent tumor.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-014-0471-6) contains supplementary material, which is available to authorized users.     

Trisomy 1q43 syndrome: a consistent phenotype with macrocephaly, characteristic face, developmental delay and cardiac anomalies

Trisomy 1q43 syndrome: a consistent phenotype with macrocephaly, characteristic face, developmental delay and cardiac anomalies: Patients with trisomy (1)(q42-qter) present with psychomotor retardation, macrocephaly, occasional presence of facial capillary naevi, cardio-vascular anomalies and small size for gestational age. We report on a girl with the same pattern of malformations, who has pure trisomy 1 q43: duplication of the region (1) (q43) and the translocation of the terminal region of the other chromosome 1 to the derivative 1, narrowing down the critical region for the characteristic traits of severe developmental delay, macrocephaly and congenital cardiac malformations.     

Maternal origin of extra marker chromosome 1Q31.1-qter and 13pter-q12.12 in a child with dysmorhic features

Maternal origin of extra marker chromosome Iq31.l-qter and 13pter-q12.12 in a child with dysmorphic features: We describe a twenty-days-old female child with dysmorphic features and chromosomal analysis with GTG-banding revealed an extra marker chromosome. Fluorescence in situ hybridization (FISH) study of extra marker chromosome confirmed to be maternal der(13) chromosome, contained 1q31.1-qter and 13pter-q11 chromosomal material and resulted from a maternal balanced translocation t(1;13)(q31.1; q12.12). The child had the majority of trisomy 1q clinical features: dysmorphic features, micropthalmia, high arched palate, long philthrum, micrognathia, hypertelorism, low set ears, short sternum, overlapping fingers, valgus of wrists, right knee and ankle joints were in flexion contractures. This is the first case of trisomy 1q with an extra marker chromosome which also contained chromosome 13pter-q12.12 material.     

Arginase deficiency manifesting delayed clinical sequelae and induction of a kidney arginase isozyme

De novo chromosome structural abnormalities cannot always be diagnosed by the use of standard cytogenetic techniques. We applied a previously developed chromosome-band-specific painting method to the diagnosis of such rearrangements. The diagnostic procedures consisted of microdissection of an aberrant chromosomal region of a given patient, polymerase chain reaction (PCR) amplification of the dissected chromosomal DNA, and subsequent competitive fluorescence in situ hybridization (FISH) using the PCR products as a probe pool on metaphase chromosomes from the patient and/or a karyotypically normal person. With this strategy, we studied 6 de novo rearrangements (6p+, 6q+, 9p+, 17p+, +mar, and +mar) in 6 patients. These rearrangements had been seen by conventional banding but their origin could not be identified. In all 6 patients, we successfully ascertained the origin. Using an aberrant region-specific probe pool, FISH signals appeared on both the aberrant region and a region of another specific chromosome pair. A reverse probe pool that was generated through the microdissection of normal chromosomes at a candidate region for the origin of the aberration hybridized with both the aberrant and the candidate regions. We thus diagnosed one patient with 17p+ as having trisomy for 14q32-qter, one with 9p+ as having trisomy for 12pter-p12, one with 6q+ as having a tandem duplication (trisomy) of a 6q23-q25 segment, one with 6p+ as having a tandem duplication (trisomy) of a 6p23-q21.3 segment, one with a supernumerary metacentric marker chromosome as having tetrasomy for 18pter-cen, and the last with an additional small marker chromosome as having trisomy for 18p11.1 (or p11.2)-q11.2. The present targeted chromosome-band-painting method provides the simple and rapid preparation of a probe pool for region-specific FISH, and is useful for the diagnosis of chromosome abnormalities of unknown origin.     

Isolation of chromosome-21-specific DNA probes and their use in the analysis of nondisjunction in Down syndrome

Summary Thirteen single-copy, chromosome-21-specific DNA probes were isolated from a recombinant library made from flow-sorted chromosome 21 DNA and regionally mapped using a panel of somatic cell hybrids. Five probes mapped in the 21q21-q22.1 region, six to the 21q22.1-qter region, and one to each of the regions 21q22.1-q22.2 and 21q22.3. Two of these probes, one of which maps in the critical region for Down syndrome, have recently been shown to be expressed at high levels in Down syndrome brain tissue (Stefani et al. 1988). Following preliminary screening for restriction fragment lenght polymorphisms (RFLPs), five polymorphisms were discovered with four of the chromosome 21 DNA probes. A frequent MspI polymorphism detected by one of the probes was used in conjunction with four previously described polymorphic chromosome 21 probes to analyse the origin of nondisjunction in 33 families with a child or fetus with trisomy 21. The parental origin of the additional chromosome 21 was determined in 12 cases: in 9 (75%) of these it was derived from the mother and in the other 3 cases (25%) it was of paternal origin. Cytogenetic analysis of Q-banding heteromorphisms was informative in three of five families tested, and in each case the RFLP results were confirmed. The meiotic stage of nondisjunction was defined with confidence in five families, the results being obtained with pericentromeric RFLP or cytogenetic markers. Recombination between two nondisjoined chromosomes was demonstrated in one family and is consistent with the view that a lack of recombination between chromosome 21 homologues or failure of their conjunction is not the invariable cause of trisomy 21.     

M-FISH applications in clinical genetics

Until recently, presence of de novo marker or derivative chromosomes was quite problematic for genetic counseling especially in prenatal diagnosis, because characterization of marker and derivative chromosomes by conventional cytogenetic techniques was nearly impossible. However, recently developed molecular cytogenetic technique named Multicolor Fluorescence in Situ Hybridization (M-FISH) which paints all human chromosomes in 24 different colors allows us to characterize marker and derivative chromosomes in a single hybridization. In this study, we applied M-FISH to determine the origin of 3 marker and 3 derivative chromosomes. Marker chromosomes were found to originate from chromosome 15 in two postnatal and one prenatal case. Of these, one of the postnatal cases displayed clinical findings of inv dup (115) syndrome and the other of infertility, and the prenatal case went through amniocentesis due to the triple test results. Karyotypes of the patients with derivative chromosomes were designated as 46,XY,der (21)t(1;21)(q32;p11), 46,XX,der(8)t(8;9)(p23;p22) and 46,XX,der(18)t(18;20)(q32;p11.2) according to cytogenetic and M-FISH studies. All of the M-FISH results were confirmed with locus specific or whole chromosome painting probes. The case with der (8)t(8;9) had trisomy 9(p22-pter) and monosomy 8(p23-pter) due to this derivative chromosome. The case with der(18)t(18;20) had trisomy 20(p11.2-pter) and monosomy 18(q32-qter). Parental origins of the derivative chromosomes were analyzed using microsatellite markers located in the trisomic chromosomal segments. Patients' clinical findings were compared with the literature.     

Deletion of 2q37 and duplication of 10q24: two cases in the same family and review of the literature.

We describe two patients (first cousins, once removed) with an unusual head shape, high arched palate, flat nasal bridge, abnormal ears, hand and feet abnormalities and other anomalies. The patients were ascertained independently and it was initially unknown that they were related to each other. Cytogenetic and fluorescent in situ hybridization (FISH) analysis identified a der(2)t(2;10)(q37.3;q24.1) unbalanced translocation resulting in loss of 2q37.3-qter and duplication 10q24.1-qter. The clinical features of these two patients are compared with previously described cases of 2q deletion and 10q duplication. These patients also emphasize the difficulty in some families of understanding and sharing genetic information and in the difficulties in obtaining an accurate pedigree in a genetics clinic.     

Distal trisomy of 10q. Report of a new case of duplication 10q25.2-25.3-->qter defined by FISH

In the present work, we report on a 2.5-year-old male patient with typical clinical features of partial trisomy of the distal third of chromosome 10 long arm. The karyotype was: 46,XY, dir dup(10)(q25.2-25.3-->qter). The identification of the duplicated segment was carried out by the fluorescence in situ hybridization technique using region-specific probes. The proband's phenotype is compared with previously reported cases.     

Clinical delineation of a patient with trisomy 1q32.qter and monosomy 5p resulting from a familial translocation 1;5

We describe a patient who had multiple malformations including ventriculomegaly, colpocephaly, corpus callosum, cerebellum and vermix hypoplasia, optic nerve hypoplasia, corneal opacity and congenital heart disease in whom a trisomy 1q32-qter and monosomy 5p derived from a t(1;5)mat was diagnosed by karyotype and FISH analysis. This trisomy/monosomy association has not been previously reported. The familial analysis of the translocation was carried out in four generations and its implications on the phenotype of the patient and genetic counseling are discussed.     

Monosomy 10q26-qter and trisomy 11q13-qter as a result ofde novo unbalanced translocation

A male infant with partial monosomy 10 q and partial trisomy 11q as a result ofde novo unbalanced translocation between the long arms of chromosomes 10 and 11: der(10)t(10;11)(q26;q13) is described. He had craniofacial dysmorphy, congenital heart defects, urogenital and cerebral anomalies, and severe developmental delay. To the best of our knowledge, this is the first report of this combination of chromosomal abnormalities.     

Partial trisomy of the distal part of 10q: a report of two Egyptian cases

Partial trisomy of the distal third of the long arm of chromosome 10 is a well defined but rare syndrome. Most cases result from an unbalanced translocation. Growth retardation, developmental delay and characteristic dysmorphic features are well described in the syndrome. This report includes 2 Egyptian cases with partial 10q trisomy involving different breakpoints. Cases were subjected to full clinical examination and detailed cytogenetic analysis using conventional and FISH studies. Results showed that the karyotype of case 1 was 46,XX,der(7)t(7;10)(p22;q23).ish(wcp7+;wcpl0+) and the karyotype of case 2 was 46,XX,der(7)t(7;10)(p22;q25).ish(wcp7+;wcp 10+). The chromosomal abnormalities in case 1 resulted from a paternal balanced translocation while case 2 resulted from a maternal balanced translocation involving chromosomes 10 and 7 in both cases. The probands' phenotypes were correlated to the breakpoints and compared to previously reported cases with partial trisomy 10q. Both cases had the well characterized phenotype of the distal trisomy of 10q in the form of mental retardation, microcephaly, characteristic dysmorphic facies and limb anomalies as trisomy in both cases involved the 10q25-->qter region. However, case 1 with 10q23-->qter duplication showed more severe clinical manifestations than case 2 with less extensive 10q25-->qter trisomy. These included severe failure to thrive, cardiac involvement and death from respiratory and heart failure. This study confirmed that unbalanced chromosome regions of the long arm of chromosome 10 play an important role in developmental malformations and that a more severe form is associated with involvement of 10q23. It also emphasizes the importance of increasing public awareness regarding these chromosomal rearrangements and the importance of genetic counseling and prenatal diagnosis to avoid recurrences and associated family stress. This was clearly demonstrated in the second family in this study as the couple refused any follow up or further investigations due to religious beliefs despite their social and educational level.     

Sister chromatid exchanges and chromosome aberrations in fibroblasts from patients with retinoblastoma

Summary The frequencies of sister chromatid exchanges (SCEs) and chromosome breaks were investigated in five diploid fibroblast strains derived from three patients with deletion 13[del(13)] retinoblastoma, one patient with a hereditary form of retinoblastoma, and one trisomy 13. The fibroblasts with del(13)(q14q22) showed slightly increased SCEs (at a P level of 5–10%), but the others, including del(13)(q12q14), the hereditary form of retinoblastoma, and trisomy 13, did not have increased SCEs as compared to normal controls. No increase in chromosome breaks was found in these fibroblasts. The results suggest that retinoblastoma is not associated with spontaneous increased chromosomal instability.