De novo dup p/del q or dup q/del p rearranged chromosomes: review of 104 cases of a distinct chromosomal mutation.

We compiled 104 constitutional de novo or sporadic rearranged chromosomes mimicking recombinants from a parental pericentric inversion in order to comment on their occurrence and parental derivation, meiotic or postzygotic origin, mean parental ages, and underlying pathways. Chromosomes involved were 1-9, 13-18, 20-22, and X (64 autosomes and 40 X chromosomes). In the whole series, mean paternal and maternal ages in cases of paternal (proved or possible; n=29) or maternal (proved or possible; n=36) descent were 31.14 and 28.31 years, respectively. Rearranged X chromosomes appeared to be of paternal descent and to arise through intrachromosomal non-allelic homologous recombination (NAHR), whereas rec-like autosomes were of either maternal or paternal origin and resulted from mechanisms proper of non-recurrent rearrangements. Except for some mosaic cases, most rearranged chromosomes apparently had a meiotic origin. Except for 8 rearranged X chromosomes transmitted maternally, all other cases compiled here were sporadic. Hence, the recurrence risk for sibs of propositi born to euploid parents is virtually zero, regardless of the imbalance's size. In brief, recombinant-like or rea chromosomes are not related to advanced parental age, may (chromosome X) or may not (autosomes) have a parent-of-origin bias, arise in meiosis or postzygotically, and appear to be mediated by NAHR, nonhomologous end joining, and telomere transposition. Because rearranged chromosomes 10, 11, and Y are also on record, albeit just in abstracts or listed in large series, we remark that all chromosomes can undergo this distinct rearrangement, even if it is still to be described for pairs 12 and 19.

A de novo sSMC(22) Characterized by High-Resolution Arrays in a Girl with Cat-Eye Syndrome without Coloboma.

Cat-eye syndrome (CES) results from trisomy or tetrasomy of proximal 22q originated by a small supernumerary marker chromosome (sSMC). Two critical regions for the major clinical features of CES (CESCRs) have been suggested; however, CES clinical presentation often does not correlate with the sSMC genetic content. We report here a CES girl without coloboma and carrier of a de novo type I sSMC(22) as determined by G- and C-banding, NOR staining and microarrays. This sSMC included 6 distal genes outside the original CESCR and led to a tetrasomy for 22q11.1-22q11.21. The patient's final karyotype was 47,XX,+psu dic(22)(q11.21).arr 22q11.1q11.21(15,250,000-17,035,860)×4 dn. The amplified region outside of CESCR included some genes that may be related to neurologic, heart and renal abnormalities. Conversely, even though the amplification included the CECR2 gene, a major candidate for eye features, there was no coloboma in the patient. The genetic delineation of the present sSMC further strengthens that the CES clinical presentation does not fit completely with the duplicated genetic content and that CES is actually a genomic disorder. Furthermore, since we observed no mosaicism, we believe that other mechanisms might be behind the variability of CES phenotypes as well, mainly those related with functional interactions among amplified genes.

Pure duplication 21q21.2-->qter due to a rea(21) in a Down syndrome girl. Remarks on nomenclature.

We report on an 8-year-old girl with a typical Down syndrome phenotype and a 46,XX,rea(21)(qter-->p12::q21.2-->qter).ish rea(21)(qter-->pl2::q21.2-->qter)(LSI 21++,AML1++) karyotype; the mother had normal chromosomes but the father was unavailable. The great resemblance of the patient's rearranged chromosome to the rec(21)dup(q) from a parental pericentric inversion suggests that it would be better depicted as a recombinant-like chromosome. Altogether, 13 recombinant-like chromosomes of de novo or unknown (parents not karyotyped) origin have been described. Although these rearranged chromosomes should formally be described as derivatives because no parental inversion is identified, we underlie that the unofficial term recombinant-like would be more appropriate because no "multiple aberrations within a single chromosome" (as required by the ISCN) have been proved, not to mention that the term derivative usually designates abnormal chromosomes resulting from a translocation between non homologous chromosomes. Accordingly, we prefer to identify such rearrangements of a single chromosome precisely with the more neutral and sanctioned term rea (expanding its use to designate a rearranged chromosome) coupled with the lengthy description of the abnormal chromosome. We assume that the rea(21) chromosomes result from illegitimate recombination between non allelic homologous LCRs located in both the short and long arms.

Variegated-like mosaicism and ring syndrome in a r(4) boy. Appraisal of 38 patients with a fairly complete ring 4.

A 13-month-old boy with normal development and growth failure of prenatal onset but no other physical stigmata had a 46,XY,r(4)(p1 6.3q35).ish (4psubtel-, WHS1+, 4qsubtel+, pantel-) de novo karyotype. The analysis of 50-106 metaphases from each of four lymphocyte cultures (three of 72 h including one without colchicine and one of 96 h) revealed a dynamic mosaicism in 22-36% of cells. We did not observe a normal cell line. Hypoploidies (excluding ring losses) were observed in 2-7% of metaphases from colchicine-arrested cultures whereas tetraploidies were observed in 2-12% of metaphases from all four lymphocyte cultures. Further FISH studies were carried out on interphase nuclei from uncultured buccal cells and lymphocytes using two alphoid (CEP 1 and 9), a dual CEP X/SRY, and (in the former only) a subtel 4p probes. We scored 70-131 nuclei per assay and found apparent heteroploidies in approximately 1-47% of cells for CEP 1, CEP 9, subtel 4p, and SRY but not for CEP X. The patient's phenotype was typical of the ring syndrome and comparable to 9/37 previous r(4) cases. Moreover, all 38 patients were alive at the time of reporting and none has developed cancer. The 2-7% rate of hypodiploid cells in colchicine-arrested cultures and the approximately 1-47% rate of apparent heteroploidies in nuclei of uncultured cells evoke the in vitro and in vivo findings in patients with mosaic variegated aneuploidy (MVA). We conclude that our observation highlights the clinical and cytogenetical overlapping between the ring syndrome and the MVA syndrome; the crucial difference is the high risk of cancer related to BUB1B mutations in the latter.

Interstitial 1q42-q44 deletion defined by FISH in a short-lived female.

We report a female newborn with a de novo 1q4 deletion ascertained by G bands but refined as an interstitial one by FISH with a subtelomeric 1q probe; hence, the final karyotype was 46,XX,del(1)(q42q44).ish subtel1q x 2. She presented a few typical features of the del(1q42) syndrome. Additionally, she showed occipital skin aplasia, interauricular communication, and intestinal perforation-obstruction and she died at 24 days of age. This observation illustrates the clinical variability of the syndrome as well as the occasional reduced survival. The redefinition by molecular cytogenetics of a terminal deletion as an interstitial one suggests that interstitial deletions are more common than reported by classic cytogenetics and can partially account for the phenotypic variability in some deletion syndromes.

A de novo (1;2;3;15;18) chromosome rearrangement with six nonreciprocal translocations.

A de novo complex chromosome rearrangement (CCR) found in a phenotypically abnormal boy was characterized by G-bands, FISH with subtelomere probes, and M-FISH. The G-banding analysis revealed involvement of chromosomes 1, 2, 3, 15, and 18 with (at least) eight breakpoints, five nonreciprocal translocations (1q --> 2q --> 8q --> 15q --> 2p --> 1q), and a 3p insertion into the der(2); there was also a presumptive deletion of 1q41. The 5 derivatives were described as follows: der(1)(1pter --> 1q32.3?::2p21--> 2pter),der(2)(1qter --> 1q42?::2q24.2 --> 2p21::3p13 --> 3p26::15q15 --> 15qter),der(3)(3qter --> 3p13:),der(15)(15pter --> 15q15::18q11 --> 18qter),der(18)(18pter --> 18q11::2q24.2 --> 2qter). The molecular assays confirmed the segmental composition of each derivative and documented the localization of most relevant telomeres. In addition to the novelty of the 1, 2, 3, 15 and 18 combination, this CCR may also be unique in the sense that it represents a cluster of 6 nonreciprocal transpositions regardless of the occurrence (or lack thereof) of secondary unbalances. Finally, there appears to be an excess of CCRs in fetuses conceived by intracytoplasmic sperm injection.

Constitutional duplication 11q23 de novo involving the MLL gene.

We report a child with mental retardation, brain anomalies and congenital heart defect. His karyotype, after G-banding and FISH with a whole chromosome probe for chromosome 11 and a locus-specific probe for the MLL gene, was 46,XY,dup(11)(q23q23).ish dup(11)(q23q23)(wcp11+, MLL++) de novo; i.e., he had a pure partial 11q23 duplication. Clinical and cytogenetic findings of the present case were compared with the 7 previously reported cases with pure partial trisomy 11q; in 6/8 cases the region 11q23 was involved. We conclude that the scarce number of cases and their heterogeneity do not allow to establish a reliable genotype-phenotype correlation.

Follow-up of an intelligent odd-mannered teenager with del(3)(p26). Remarks on authorship and ethical commitment.

A male teenager formerly found to have a 46,XY,del(3)(p26)de novo karyotype was restudied. At the age of 14(8/12) yr, he attends the last grade of middle school and was a cooperating teenager with slender habitus, severe myopia, prominent nose, sacral dimples, pubertal stage Tanner III, and multiple surgical scars. Neuropsychological studies revealed a full scale IQ of 95 with slow performance (WISC-IV Spanish test) as well as an internalizing behavioral profile, poor social skills, a mild attention deficit, somatic complaints, and a feminized gender role. FISH with the 3p subtelomeric probe revealed that the deleted chromosome actually lacked the specific signal (n=10 cells). The patient's average intelligence confirms that euchromatic imbalances do not necessarily cause mental retardation and suggests that his deletion actually included the CALL gene, the Contactin 4 gene and other 3p26 genes related to intellectual capabilities; yet, the resulting hemizygosity either did not lead to haploinsufficiency or was minimally expressed. Moreover, the patient's peculiar cognitive and behavioral profile suggests that the 3p26 deletion is associated with a distinctive neuropsychological phenotype. Incidentally we comment on authorship and publication ethics in order to urge our institutional ethics committee to arbitrate authorship conflicts and thereby be consistent with its ethical commitment.

Centromeric association of a microchromosome Y in two male patients.

We characterized two Y-ring microchromosomes (MC) found in an azoospermic patient with Turner stigmata (case A) and a male infant with hypospadias (case B). The karyotypes, as assessed by banding, FISH, and STRs/STSs analyses, were 46,X,r(Y).ish r(Y)(p11.3q11.222)(SRY+,DYZ3+) and 46,X,+r(Y)/45,X.ish r(Y)(p 11.2q11.2)(Xp/Yp-,SRY+,DYZ3+) respectively. In both cases, we evaluated the association of each MC with the centromere of the nearest and second nearest chromosomes in G-banded metaphases by means of measuring the intervening distance according to two criteria: < or =1 time or < or =3 times the size of the MC in each metaphase. The case A's MC was associated 84 times in 98 cells according to the latter or less strict criterion and two times in 98 cells according to the strict criterion; the corresponding values for case B were 84 and two in 95 cells respectively. The centromeric association appears to be related to centromeric attraction mediated by heterochromatin or centromere-specific proteins, the replication time, and the Rabl orientation.

Bovine herpes virus gD protein produced in plants using a recombinant tobacco mosaic virus (TMV) vector possesses authentic antigenicity.

A tobacco mosaic virus (TMV)-based vector was utilized for expression of a cytosolic form of the bovine herpesvirus type 1 (BHV-1) protein glycoprotein D (gDc). Nicotiana benthamiana plants were harvested 7 days after inoculation with RNA transcripts derived from the TMV-gDc recombinant virus. Recombinant gDc protein of expected electrophoretic mobility accumulated in inoculated leaves to a concentration of about 20 micrograms/g of fresh leaf tissue. Oil-based vaccines were formulated with crude foliar extracts to immunize mice parentally. After a single injection, animals developed a sustained and specific response to both the isolated gD and native virus particles. Cattle vaccinated with the same gDc containing extracts developed specific humoral and cellular immune responses directed against both the viral gD and BHV-1 particles. Most importantly, animals vaccinated with the plant-produced gDc showed good levels of protection after challenge with the virulent BHV-1. Virus excretion was drastically reduced in these animals, reaching levels comparable to animals vaccinated with a commercial BHV-1 vaccine. The positive immunological characterization obtained for the gDc, indicated that an important part of the natural conformation was retained in the plant recombinant protein.

Rescue of the colony-stimulating factor 1 (CSF-1)-nullizygous mouse (Csf1(op)/Csf1(op)) phenotype with a CSF-1 transgene and identification of sites of local CSF-1 synthesis.

Colony-stimulating factor 1 (CSF-1) regulates the survival, proliferation, and differentiation of mononuclear phagocytes. It is expressed as a secreted glycoprotein or proteoglycan found in the circulation or as a biologically active cell-surface glycoprotein. To investigate tissue CSF-1 regulation, CSF-1-null Csf1(op)/Csf1(op) mice expressing transgenes encoding the full-length membrane-spanning CSF-1 precursor driven by 3.13 kilobases of the mouse CSF-1 promoter and first intron were characterized. Transgene expression corrected the gross osteopetrotic, neurologic, weight, tooth, and reproductive defects of Csf1(op)/Csf1(op) mice. Detailed analysis of one transgenic line revealed that circulating CSF-1, tissue macrophage numbers, hematopoietic tissue cellularity, and hematopoietic parameters were normalized. Tissue CSF-1 levels were normal except for elevations in 4 secretory tissues. Skin fibroblasts from the transgenic mice secreted normal amounts of CSF-1 but also expressed some cell-surface CSF-1. Also, lacZ driven by the same promoter/first intron revealed beta-galactosidase expression in hematopoietic, reproductive, and other tissue locations proximal to CSF-1 cellular targets, consistent with local regulation by CSF-1 at these sites. These studies indicate that the 3.13-kilobase promoter/first intron confers essentially normal CSF-1 expression. They also pinpoint new cellular sites of CSF-1 expression, including ovarian granulosa cells, mammary ductal epithelium, testicular Leydig cells, serous acinar cells of salivary gland, Paneth cells of the small intestine, as well as local sites in several other tissues.

In search of a 9q13 latent centromere in 9qh polymorphic inversions.

In search of a 9q13 latent centromere in 9qh polymorphic inversions: The presence of alphoid sequences in 9q13 has prompted the suggestion that such a region could harbor a latent centromere which under certain circumstances may appear as a neocentromere. We tested this hypothesis by means of FISH with a centromere 9-specific alphoid probe in lymphocyte metaphases from 13 unrelated individuals with a 9qh polymorphic inversion. Since all inverted chromosomes had the alphoid signal onto the primary constriction, it was not possible to identify any neocentromere . We believe, however, that the number of cases was not enough to conclude that all the polymorphic inversions of chromosome 9 are genuine.

Interchange trisomy 21 by t(1;21)(p22;q22)mat.

Interchange trisomy 21 by t(1:21)(p22:q22)mat: Interchange trisomy 21 by t(1;21)(p22;q22)mat was identified in a sporadic patient with Down syndrome. With a 21q22 specific probe, we observed signals on both normal 21 chromosomes and on the der. We reviewed the 23 published reports of families with reciprocal translocations leading to viable offspring with interchange trisomy 21. The breakpoints in chromosome 21 were mainly located in 21q (19/24 instances, including the present report) and in 19/23 cases the other chromosome involved in the translocation was <> (pairs 1-12). The underlying 3:1 segregation occurred mainly in carrier mothers; only one patient presented a de novo imbalance and in another case the father was the carrier. In addition, there were 4 instances of concurrence with another unbalanced segregation (adjacent-1 or tertiary trisomy) and 3 families with recurrence of interchange trisomy 21. The mean age of 14 female carriers at birth of interchange trisomy 21 offspring (24.8 yr) was lower that the mean (28.3 yr) found in a larger sample of mothers of unbalanced offspring due to 3:1 segregation (mostly tertiary trisomics) and was not increased with respect to the general population average. Overall, these data agree with previous estimates regarding recurrence risk (9-15%) and abortion rate (about 28%) in female carriers ascertained through an interchange trisomic 21 child.

The Cbl protooncoprotein stimulates CSF-1 receptor multiubiquitination and endocytosis, and attenuates macrophage proliferation.

Colony-stimulating factor-1 (CSF-1) activation of the CSF-1 receptor (CSF-1R) causes Cbl protooncoprotein tyrosine phosphorylation, Cbl-CSF-1R association and their simultaneous multiubiquitination at the plasma membrane. The CSF-1R is then rapidly internalized and degraded, whereas Cbl is deubiquitinated in the cytoplasm without being degraded. We have used primary macrophages from gene-targeted mice to study the role of Cbl. Cbl-/- macrophages form denser colonies and, at limiting CSF-1 concentrations, proliferate faster than Cbl+/+ macrophages. Their CSF-1Rs fail to exhibit multiubiquitination and a second wave of tyrosine phosphorylation previously suggested to be involved in preparation of the CSF-1-CSF-1R complex for endocytosis. Consistent with this result, Cbl-/- macrophage cell surface CSF-1-CSF-1R complexes are internalized more slowly, yet are still lysosomally degraded, and the CSF-1 utilization by Cbl-/- macrophages is reduced approximately 2-fold. Thus, attenuation of proliferation by Cbl is associated with its positive regulation of the coordinated multiubiquitination and endocytosis of the activated CSF-1R, and a reduction in the time that the CSF-1R signals from the cell surface. The results provide a paradigm for studies of the mechanisms underlying Cbl attenuation of proliferative responses induced by ligation of receptor tyrosine kinases.

Single cell chromosome rearrangements in indivuduals with reproductive failure

Single cell chromosome rearrangements (SCCR) are incidental findings in cell cultures. Nevertheless, some authors have implicated them in habitual abortion. Ninety individuals classified in four groups were prospectively studied: A) individuals with spontaneous abortions, malformed children or molar pregnancies (N = 36); B) azoospermic males (N = 14); C) individuals with one or more children with either de novo or inherited, constitutional, chromosome abnormalities (N = 26), and D) individuals with healthy children and no reproductive failure (control group, N = 14). Lymphocyte chromosome preparations were stained for GTG bands, and 50-100 metaphases were scored per individual. The rearrangements observed were translocations, deletions, duplications, isochromosomes, rings, fragments and markers. Thirty-four individuals (21 males, 13 females) had a range of 1-5 SCCR. Four had rearrangements only of chromosomes 7 and 14. SCCR frequency (with the exception of rearrangements involving chromosomes 7 and 14) was 0.0063, while that of rearrangements between chromosomes 7 and 14 was 0.0010. Statistical intergroup comparisons c2 with Yates correction) did not show significant differences. Hence, the occurrence of SCCR in our sample was found to be independent of ascertainment mode and sex.

The effects of colony-stimulating factor-1 on the distribution of mononuclear phagocytes in the developing osteopetrotic mouse.

Colony-stimulating factor-1 (CSF-1), the primary regulator of mononuclear phagocyte (Mphi) production, exists as either a circulating or cell surface, membrane-spanning molecule. To establish transplacental transfer of maternal CSF-1, gestational day-17 mothers were injected intravenously with 125I-mouse CSF-1 or human rCSF-1, and the 125I-cpm or human CSF-1 concentrations were measured in fetal tissue, placenta, and fetal/maternal sera. Biologically active CSF-1 crossed the placenta and peaked in fetal tissue, placenta, and serum 10 minutes after injection. The role of CSF-1 in perinatal Mphi development was examined by studying the CSF-1-deficient osteopetrotic (csfmop/csfmop) mouse. Fetal/neonatal mice, derived from matings of either +/csfmop females with csfmop/csfmop males or the reciprocal pairings, were genotyped and tissue Mphi identified and quantified. In the presence of circulating maternal CSF-1 (+/csfmop mother), Mphi development in csfmop/csfmop liver was essentially complete at birth relative to +/csfmop littermates, but significantly reduced in spleen, kidney, and lung. In the absence of circulating maternal CSF-1 (csfmop/csfmop mother), Mphi numbers at birth were reduced in csfmop/csfmop liver relative to the offspring of +/csfmop mothers, but were similar in spleen, kidney, and lung. We conclude that CSF-1 is required for the perinatal development of most Mphi in these tissues. Compensation for total absence of local CSF-1 production by circulating, maternal CSF-1 is tissue-specific and most prominent in liver, the first fetal organ perfused by placental blood. However, because some Mphi developed in the complete absence of CSF-1, other factors must also be involved in the regulation of macrophage development.

Effect of the colony-stimulating factor-1 null mutation, osteopetrotic (csfm(op)), on the distribution of macrophages in the male mouse reproductive tract.

Macrophages are found throughout the male reproductive tract and its accessory glands. Mice homozygous for a null mutation (csfm(op)) in the gene for the mononuclear phagocytic growth factor colony-stimulating factor-1 (CSF-1) have a significantly lower density of macrophages, defined by the mononuclear phagocytic antigen F4/80, in the testis, cauda and caput epididymis, prostate, seminal vesicles, and vas deferens. These data indicate that CSF-1 is the major growth factor regulating the occurrence of macrophages in male reproductive tissues. The residual macrophages were correctly located in the tissue except in the caput epididymis, where they failed to take up positions adjacent to the tubular epithelium. Restoration of circulating CSF-1 concentrations in csfm(op)/csfm(op) males totally restored F4/80+ cell density in the testis and caput and cauda epididymis and partially restored their density in the vas deferens and seminal vesicles but failed to affect density in the prostate. This failure to correct all populations with circulating CSF-1 suggests the requirement for local synthesis of CSF-1 at appropriate developmental stages and/or its expression in a cell surface-associated form. The absence of macrophages in the testis and epididymis of csfm(op)/csfm(op) mice correlates with dysfunction in these tissues, suggesting that macrophages play important nonimmunological roles in these tissues.