Partial 9p Research Articles

The terminal 760 kb region on 4p16 is unlikely to be the critical interval for growth delay in Wolf–Hirschhorn syndrome

In a recent issue of the journal, Concolino et al 1 describe a patient with severe growth retardation and a ring chromosome 4, in which a 760 kb deletion within...

Partial trisomy and partial monosomy resulting from a reciprocal segregating in a large family

Partial trisomy 7p with partial monosomy 9p is a rare disorder with only 3 cases reported. Both these abnormalities i.e., partial trisomy 7p and partial monosomy 9p result in distinct clinical phenotypes. However, patients with combined 7p trisomy/9p monosomy present with a phenotype consistent with trisomy 7p. We present a fourth case of trisomy 7p/monosomy 9p with long term follow-up and document the medical complications associated with this disorder. Long term follow-up of patients with chromosome abnormalities provides a unique opportunity to document the medical history and complications associated with such abnormalities.

Pallister–Killian syndrome: tetrasomy of 12pter→12p11.22 in a boy with an analphoid, inverted duplicated marker chromosome

Supernumerary marker chromosomes (SMCs) without detectable alphoid DNA are predicted to have a neocentromere and have been referred to as mitotically stable neocentromere marker chromosomes (NMCs). Here we report the molecular cytogenetic characterization of a new case of Pallister-Killian syndrome (PKS) in a boy with an analphoid, inverted duplicated NMC derived from 12pter-->12p11.22 in his fibroblasts by using high-resolution comparative genetic hybridization (HR-CGH), multiplex fluorescent in situ hybridization (FISH) and bacterial artificial chromosome (BAC)-FISH mapping analyses with various alpha-satellite DNA probes, subtelomere probes and BAC-DNA probes. Precise identification of SMCs and NMCs is of essential importance in genetic counseling. HR-CGH is a more informative and often a faster way of precisely identifying the origin of SMCs. This case is the third report of PKS with an NMC containing an inverted duplication of partial 12p with available clinical data. These observations may help to determine the critical region for PKS and the mechanisms leading to the origin of the NMC derived from 12pter-->12p11.22 - a region that appears to be susceptible to the formation of neocentromeres. The use of subtelomeric probe PCP12p in buccal cells appears superior to the use of the centromere probe D12Z3 for the diagnosis of the PKS.

Recurrent inverted duplication of 2p with terminal deletion in a patient with the classical phenotype of trisomy 2p23‐pter

Inverted duplications with terminal deletions have been reported in an increasing number of chromosomes and are probably more frequent than suspected until recently. We describe the cytogenetic and molecular characterization of an inverted duplication of chromosome 2p in an 8-year-old girl. Firstly interpreted as partial duplication 2p, the rearrangement was in fact an inverted duplication associated with a terminal deletion of the short arm of the rearranged chromosome 2, the latter not being detectable by cytogenetic analysis. The complete karyotype was: 46,XX,add(2)(p23)dn.ish inv dup del(2)(:p23.2-->p25.3::p25.3-->qter) (wcp2+,N-MYC++,2pter-)dn. We precisely define the extension of both the duplication and the deletion using bacterial artificial chromosomes clones spanning the regions. The size of the inverted duplicated segment was estimated to be 28 Mb, spanning from 2p23.2 to 2p25.3, and an approximately 1.6 Mb segment at 2pter-p25.3 was deleted in the abnormal chromosome. The physical findings noted in our patient include prominent forehead, hypertelorism, flat nasal bridge, and low-set and large ears. In addition, she had congenital heart defect and scoliosis. Her psychomotor development was severely delayed from the beginning. All these clinical features are the same as observed for the typical trisomy 2p23-pter syndrome. The phenotypic effects of the terminal deletion of 2p in addition to the trisomy are discussed. This is the third patient presenting with a severe clinical phenotype and a de novo inv dup del (2p).

Cytogenetic analysis of partial trisomy 9p resulting from a reciprocal balanced 9/21 translocation

In this study, a four-generation Chinese family in Nanyang, Henan Province was identified with partial trisomy 9p syndrome. Of the 23 family members studied, six were characterized with mental retardation and mild facial and little finger anomalies. All affected family members demonstrated significant intrafamilial homogeneous phenotype except concomitance epilepsy in proband. On the basis of G-banding, the proband showed a translocation between chromosomes of 9p and 21q and partial 9p trisomy. The karyotype was 46, XY, der (21) t (9; 21) (9p22.2; 21q22.3) pat. Further karyotyping of other affected members and their patients in this family revealed translocation of chromosomes of 9p and 21q, with partial 9p trisomy in all affected members. The partial 9p trisomy was the direct result of abnormal segregation of a balanced translocation cell between chromosome 9 and 21 in one of the parents. The extra distal half of the short arm of chromosome, 9pter-->9p21, is responsible for the major clinical features such as mental retardation and mild facial anomaly. The cause of epilepsy in proband was discussed.

Distribution of the oscillator strengths in the 2p absorption spectra of 3d transition metal films

The absorption cross-sections in the region of the resonance structure of the 2p ionization threshold of metal films are originally measured for the total series of 3d metals from Sc to Cu. The partial 2p absorption cross-sections are found, and the integral oscillator strengths are determined. The linear dependence of the sum of oscillator strengths in the range from 0 to 80 eV above the L3 absorption edge on the number of unfilled 3d states is established. The dependence breaks down for Cr, Fe, and Ni.

A report of pure 7p duplication syndrome and review of the literature

We report on a case of a 9-month-old female infant with a direct duplication of the 7p13-p22.1 chromosome region diagnosed by combining conventional cytogenetic, FISH, and multicolor banding (MCB) studies. Traditional G-banding detected a partial 7p duplication, which was further demonstrated to be entirely of chromosome 7 origin by using a whole chromosome paint for chromosome 7, and derived from 7p13-p22.1 by MCB. The infant presented with characteristic dysmorphic features, psychomotor retardation, and generalized hypotonia. The phenotypic manifestations of partial 7p trisomy with or without other chromosome involvement are briefly reviewed. Our observations in combination with other cases confirm that 7p trisomy due to dir dup(7p) can be regarded as a defined chromosome syndrome.

Recombinant chromosome 4 resulting from a maternal pericentric inversion in two sisters presenting consistent dysmorphic features

The chromosome 4 inversion with breakpoints p13-p15q35 results in a recombinant 4 [rec(4)] chromosome with a partial 4p duplication/4q deletion in approximately 80% of the carriers' offspring. However, whether the recombinant 4p syndrome can be recognized as a clinical entity is still open to controversy. We report on two sisters diagnosed with rec(4) resulting in a partial 4p trisomy/4q deletion that was inherited from their mother, who is a carrier of inv(4)(p14q35). Both probands presented phenotypes consistent with those observed in other children with rec(4)parental, supporting the proposal that the rec(4)parental syndrome is a distinct entity among dup(4p) cases and may be suspected on the basis of the pattern of clinical symptoms. To the best of our knowledge this is only the second report of family with two probands affected with a recombinant chromosome 4 arising from a parental pericentric inversion.

Case report: Y;6 translocation with deletion of 6p

Translocations between the Y chromosome and an autosome are rare. We report a phenotypic male with a translocation between the Y chromosome and chromosome 6p, leading to partial 6p monosomy and XX male syndrome. He is the second child to be reported with this karyotype. Phenotypic findings included growth retardation, severe developmental delay, a Dandy-Walker malformation, cardiac and urogenital abnormalities, bilateral hearing loss, cleft palate, severe kyphoscoliosis, minor digital anomalies, and a hypoplastic phallus. Craniofacial dysmorphism consisted of dolichocephaly, hypertelorism, down-slanting palpebral fissures, depressed nasal bridge and a tented upper lip. Cytogenetic analysis showed the karyotype 46,XX,der(6)t(Y;6)(p11.2;p23).ish der(6)(SRY+,6pTEL48-). The effects of partial monosomy 6p are discussed and compared to other patients with interstitial and terminal 6p deletions.

Prenatal detection of ade novo terminal inverted duplication 4p in a fetus with the Wolf-Hirschhorn syndrome phenotype

To present the prenatal diagnosis of a de novo terminal inversion duplication of the short arm of chromosome 4 and a review of the literature. An amniocentesis for chromosome analysis was performed at 33 weeks' gestation because ultrasound examination showed a female fetus with multiple abnormalities consisting of severe intrauterine growth retardation, microcephaly, a cleft lip and renal hypoplasia. Cytogenetic analysis and FISH studies of the cultured amniocytes revealed a de novo terminal inversion duplication of the short arm of chromosome 4 characterized by a duplication of 4p14-p16.1 chromosome region concomitant with a terminal deletion 4p16.1-pter. The karyotype was thus: 46,XX, inv dup del (4)(:p14-->p16.1::p16.1-->qter). The parents opted to terminate the pregnancy. Fetopathological examination showed dysmorphic features and abnormalities consistent with a Wolf-Hirschhorn syndrome (WHS) diagnosis, clinical manifestations of partial 4p trisomy being mild. Although relatively rare, inverted duplications have been reported repeatedly in an increasing number of chromosomes. Only two previous cases with de novo inv dup del (4p) and one with tandem dup 4p have been reported, all of them associated with a 4pter deletion. We report the first case diagnosed prenatally. Breakpoints are variable, resulting in different abnormal phenotype. In our case, clinical manifestations resulted in a WHS phenotype.

Diagnostic molecular genetics and its application to clinical decision in brain tumors

The authors review new insights into molecular genetics-based diagnosis and show the applications to clinical decisions we are conducting in some types of brain tumors. Among the many genetic alterations noted in astrocytic tumors, the methylation status of a DNA repair enzyme, O 6-methyl-guanine-DNA methyltransferase (MGMT), is now in the limelight. It has been reported that the methylation status of MGMT determines its response to alkylating agents. Our target for molecular diagnosis within gliomas is the oligodendroglial tumor. We conducted cytogenetic and LOH analysis of 14 oligodendroglial tumors using fluorescent in situ hybridization (FISH) and microsatellite analysis, focusing on chromosomes 1p and 19q as well as 17p. With the clinical data of these patients, a combined loss of 1p and 19q would predict longer survival, but the loss of p53 could worsen the prognosis even with histological grade II. This diagnostic approach can be accepted and allows physicians to select an appropriate therapeutic modality including aggressive chemotherapy. Chromosome 22q loss has classically been a molecular marker of meningioma. We have conducted molecular genetic testing on a total of 63 tumors, including 15 atypical and 7 anaplastic meningiomas. A high incidence of deletion of at least part of 1p was observed in 67% of atypical and 86% of anaplastic meningiomas, showing molecular evidence for further treatment after simple removal. In addition, 12% of histologically benign meningiomas harbored 1p loss, indicating that patients with these tumors may need careful clinical follow-up with neuroimaging for recurrence. Detection of the allelic status of chromosome 1p may assist physicians in predicting the clinical prognosis.

20-Mb duplication of chromosome 9p in a girl with minimal physical findings and normal IQ: narrowing of the 9p duplication critical region to 6 Mb.

We studied the case of a girl with a partial 9p duplication, dup(9)(p22.1 --> p13.1). Molecular cytogenetics studies defined the chromosome 9 rearrangement as a direct duplication of 20 Mb from D9S1213 to D9S52. Microsatellite analysis demonstrated the presence of a double dosage of the paternal alleles and demonstrated that the duplication occurred between sister chromatids. The patient's phenotype was almost normal, with a few minor anomalies (dolichocephaly, crowded teeth, high arched palate) and normal IQ. The breakpoint's location in this patient and previously reported cases suggest that the critical region for the 9p duplication syndrome lies within a 6-Mb portion of chromosome 9p22 between markers D9S267 and D9S1213.

Detection of three novel translocations and specific common chromosomal break sites in malignant melanoma by spectral karyotyping

Chromosomal aberrations in malignant melanoma cells have been reported using standard chromosome banding analysis and comparative genomic hybridization. To identify marker chromosomes and translocations that are difficult to characterize by standard banding analysis, 15 early passage malignant melanoma cell lines were examined using spectral karyotyping. All 15 tumor cell lines had lost all or part of 1p and 10q. Losses of material on chromosome arms 4p (12/15), 6q (12/15), 9p (15/15), 12p (13/15), 12q (13/15), 13q (11/15), and 19q (14/15) were the next most frequent events. Gain of chromosome arms 1q (11/15), 6p (13/15), and 20q11 (14/15) was also observed. Interestingly, we identified translocations der(12)t(12;20)(q15;q11), der(19)t(10;19)(q23;q13), and der(12)t(12;19)(q13;q13) in 4/15 tumors. Three recurring translocations involving four of the most frequent break points were detected. The identification of recurring translocations and unique chromosome break points in melanoma will aid in the identification of the genes that are important in the neoplastic process.

Differences in genetic alterations between primary lobular and ductal breast cancers detected by comparative genomic hybridization.

Infiltrating ductal (DC) and lobular carcinoma (LC) of the breast represent the most frequently observed varieties of invasive breast cancer, characterized by differences in their histological and clinical properties. Although comparative genomic hybridization (CGH) of invasive breast carcinomas has revealed a complex and consistent pattern of DNA copy number changes, the data with regard to type specific aberrations are limited. A comprehensive study was therefore performed on 19 LCs and 29 DCs to ascertain type-specific differences of unbalanced DNA copy number changes by CGH. Statistical analysis revealed significantly higher frequencies for underrepresentation of chromosomes 16q (p<0.01), 22 (p<0.05), and 17q (p<0.05), and a lower frequency for overrepresentation of chromosome 8q (p<0.01) in LC. Similar frequencies of non-random chromosomal changes in LC and DC were obtained for gain of 1q (74%/59%) and loss of 19p (53%/52%), parts of 1p (42%/41%) and 11q (21%/24%). Less frequently, gains mainly involving parts of chromosomes 20q, 20p, 3q, and 5p and partial losses of chromosomes 17p and 13 were observed in both groups of tumours. Minimal regions of overlapping amplifications were mapped to 17q23 exclusively in DC (17%) and 11q13-q14 in both DC and LC (21% and 11%, respectively). High occurrences of DNA copy number decreases were detected at the distal part of chromosomes 1p, 19 and 22, but further analysis is required to confirm these imbalances. It is suggested that the observed differences are involved in the development of type-specific properties of DC and LC.

Clinical and molecular cytogenetic analysis of a rare case of mosaicism for partial monosomy 3p and partial trisomy 10q in human

The results of comprehensive clinical examination and molecular cytogenetic analysis of a patient carrying chromosome 3p+ in 69% of the peripheral blood lymphocytes are presented. Using microdissection of the metaphase chromosomes followed by DOP-PCR, a DNA library specific for the abnormal chromosome was obtained. By fluorescence in situ hybridization (FISH) of this DNA library with chromosomes from the patient and a healthy donor, the aberrant chromosome was identified as der(3)t(3;10)(3p25;q24.3). Since this chromosome was present in only a proportion of patient's cells studied and no chromosome aberrations were revealed in cells of his parents, the der(3)t(3;10) is suggested to appear de novo. The cells carrying der(3)t(3;10) are monosomic for a proportion of 3p25 and trisomic for 10q24.3-->qter. The developmental malformations revealed in the patient, such as the specific features of facial skeleton, mental retardation, microcephaly, and others are similar to those described previously in patients with partial 3p monosomy and 10q trisomy.

Molecularly defined interstitial tandem duplication 6p case with mild manifestations

An interstitial tandem duplication of 6p21.1-p22.2 was found in a girl at 11 months of age when she was evaluated for developmental delay. Previous cases reported with partial 6p duplication usually have involved terminal duplications, with breakpoints ranging from 6p11 to 6p25. Our patient exhibits a milder phenotype compared to the previously reported cases in the literature. Features that she has in common with the other cases include craniofacial anomalies, such as broad nasal bridge and bulbous tip, thin lips, incomplete development of the scapha helix bilaterally, mild spastic paraparesis of the lower extremities, gross motor delay, and mild cognitive delays.

Molecular definition of Xq common-deleted region in patients affected by premature ovarian failure.

High-resolution cytogenetic analysis of a large number of women with premature ovarian failure (POF) identified six patients carrying different Xq chromosome rearrangements. The patients (one familial and five sporadic cases) were negative for Turner's stigmata and experienced a variable onset of menopause. Microsatellite analysis and fluorescent in situ hybridization (FISH) were used to define the origin and precise extension of the Xq anomalies. All of the patients had a Xq chromosome deletion as the common chromosomal abnormality, which was the only event in three cases and was associated with partial Xp or 9p trisomies in the remaining three. Two of the Xq chromosome deletions were terminal with breakpoints at Xq26.2 and Xq21.2, and one interstitial with breakpoints at Xq23 and Xq28. In all three cases, the del(X)s retained Xp and Xq specific telomeric sequences. One patient carries a psu dic(X) with the deletion at Xq22.2 or Xq22.3; the other two [carrying (X;X) and (X;9) unbalanced translocations, respectively] showed terminal deletions with the breakpoint at Xq22 within the DIAPH2 gene. Furthermore, the rearranged X chromosomes were almost totally inactivated, and the extent of the Xq deletions did not correlate with the timing of POF. In agreement with previous results, these findings suggest that the deletion of a restricted Xq region may be responsible for the POF phenotype. Our analysis indicates that this region extends from approximately Xq26.2 (between markers DXS8074 and HIGMI) to Xq28 (between markers DXS 1113 and ALD) and covers approximately 22 Mb of DNA. These data may provide a starting point for the identification of the gene(s) responsible for ovarian development and folliculogenesis.

FISH analysis in detecting 9p duplication (p22p24)

Authors report on a case of partial 9p duplication, involving the 9p22-9p24 region. This represents the second case of such duplication in which the breakpoints were precisely defined using fluorescence in situ hybridisation (FISH) with chromosome 9 specific painting and YAC DNA probes, localised onto 9p22-9p24 region. FISH analysis pinpointed chromosome breakpoints in dup(9)(p22p24) and excluded an insertion or a translocation from other chromosomes. The present report supports the segment 9p22-9p24 as the critical region for the observed phenotype of the duplication 9p syndrome.

Familial dup(8)(p12p21.1): mild phenotypic effect and review of partial 8p duplications.

We describe a family with direct transmission of a duplication of 8p12-->8p21.1. The phenotype of affected relatives included mild mental retardation but no minor anomalies. The duplication was identified by means of GTG-banding and fluorescence in situ hybridization with a probe specific for 8p12 generated by microdissection and degenerate oligonucleotide primed-polymerase chain reaction. Assay of glutathione reductase, which has been localised to 8p21.1, was significantly increased when compared with controls with normal chromosomal constitution. To the best of our knowledge, a proximal direct duplication of 8p restricted to subbands p12-->p21.1 has not been reported so far. The reported aberration is compared with other partial duplications of 8p, in particular to inversion duplications 8p and to small direct distal duplications involving 8p23.1. Am. J. Med. Genet. 94:306-310, 2000.

Proximal 5p trisomy resulting from a marker chromosome implicates band 5p13 in 5p trisomy syndrome

We describe an infant with trisomy of (5)(p10p13.1) resulting from a de novo marker chromosome. The marker's origin was identified by chromosome microdissection and reverse in situ hybridization. The clinical findings are compared to those of other partial and complete 5p duplications. This case further defines the critical region of 5p trisomy syndrome to proximal 5p.