Distinct prenatal ultrasonographic cranial and cerebral findings in terminal deletion of the short arm of chromosome 1.
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Abnormalities, Multiple↗
Biomedical subjects
J R Vermeesch
Publications and source records attributed to J R Vermeesch.
Ring syndrome caused by ring chromosome 7 without loss of subtelomeric sequences.
Ring chromosome 7 is an unusual chromosome anomaly. Here we describe a patient with ring chromosome 7 and we show that both subtelomeres are still present. The diagnosis agrees with 'ring syndrome'. This report helps to further delineate the clinical manifestations of 'ring syndrome' and to distinguish the phenotypic consequences of the presence of a ring chromosome 7 from the phenotypic consequences of terminal chromosome 7 submicroscopic deletions.
Chromosome Banding↗
Mosaicism for duplication 12q (12q13-->12q21.2) accompanied by a pericentric inversion in a dysmorphic female infant.
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Abnormalities, Multiple↗
Small terminal 10q26 deletion in a male patient with Noonan-like stigmata: diagnosis by cytogenetic and FISH analysis.
A male patient is reported with terminal 10q26 deletion, developmental retardation, special behaviour, and multiple clinical anomalies including hypotonia, short stature of postnatal onset, short webbed neck, craniofacial dysmorphism, pectus excavatum with widely spaced small nipples, cryptorchidism with scrotal hypoplasia, limb and musculoskeletal anomalies. The facial dysmorphism mainly consisted of trigonocephaly, a long, triangular and asymmetrical face, hypertelorism with pseudoepicanthus, broad nasal bridge, high-arched palate, retrognathia, low-set dysplastic auricles and, on ophthalmologic examination, strabismus, astigmatism and myopia. Some of these clinical stigmata were suggesting the diagnosis of Noonan syndrome. The extremities showed special features including shortening of proximal limbs, brachydactyly with syndactyly of toes II-III and left fingers III-IV, hypoplastic toenails and joint abnormalities. A diastasis of abdominal muscles was noted and, on X-rays a thoracic scoliosis and bilateral coxa valga were evidenced. Analyses of G- and T-banded chromosomes complemented by FISH analyses using different subtelomere probes detected a terminal 10q26 deletion. Subsequent FISH studies using different probes of the 10q26 region were performed in an attempt to closely define the breakpoint and the extent of the deletion and, thereby, to allow karyotype/phenotype comparison between this patient and a previously reported case with an apparently similar 10q26 deletion.
Chromosome Deletion↗
Human sphingosine-1-phosphate lyase: cDNA cloning, functional expression studies and mapping to chromosome 10q22(1).
Sphingosine-1-phosphate lyase catalyzes the last step in sphingolipid breakdown, the cleavage of phosphorylated sphingoid bases such as sphingenine-1-phosphate. The latter lipid is not only a catabolite, but can influence as an inter- and/or intracellular second messenger many cellular processes. To allow for the diagnosis of human disorders that might be linked to a deficient lyase, the human sphingosine-1-phosphate lyase cDNA was cloned. The obtained cDNA encoded a protein of 568 amino acids with a calculated molecular mass of 63492 Da. Hydropathy plots revealed the presence of one membrane span near the amino-terminal which is however not required for enzyme activity since recombinant poly-His-tagged lyase, lacking this membrane span, was functionally active. Site-directed mutagenesis disclosed the importance of the cysteine residues 218 and 317 for the cleavage reaction. Northern analysis showed the presence of rare large-sized mRNAs of 6.7, 5.8 and 4 kb and the highest expression in liver. By fluorescent in situ hybridization, the gene was mapped to chromosome 10q22.
Aldehyde-Lyases↗
Microdissection and FISH investigations in acute myeloid leukemia: a step forward to full identification of complex karyotypic changes.
Complex chromosomal rearrangements in malignant hemopathies frequently remain unclarified because of paucity of material for further fluorescence in situ hybridization analyses and/or lack of suitable probes. Chromosome microdissection (MD) can be an adequate approach to elucidate chromosome aberrations unrecognizable by conventional karyotyping. We applied MD in two patients with acute myeloid leukemia (AML) and unidentified chromosome changes at karyotype. Microdissection of a ring chromosome in an AML-M5 case revealed 21q polysomy. In an AML-M4 case, MD of an add(15p) disclosed a t(8;15) with over-representation of both 8q22 and 8q24 bands. YAC probes were helpful in showing duplication of the ETO gene at 8q22, and amplification of C-MYC, at 8q24.
Aneuploidy↗
Characterization of centromere alterations in liposarcomas.
Supernumerary ring and large marker chromosomes are a characteristic of atypical lipomas and well-differentiated liposarcomas (ALP-WDLPS) and are composed of amplified 12q14-15 sequences in association with variable segments from other chromosomes. Although stably transmitted, these chromosomes contain centromeric alterations, showing no detectable alpha-satellite sequences. We performed C-banding, fluorescence in situ hybridization, and immunostaining with anti-centromere antibodies in 8 cases of liposarcomas with supernumerary rings and large markers, including 5 ALP-WDLPS and 3 dedifferentiated-LPS and high-grade LPS. Our results with alpha-satellite probes and anti-CENPB antibodies confirm the lack of detectable alpha-satellite sequences in the five ALP-WDLPS supernumerary chromosomes, whereas centromeric activity was proved by the detection of kinetochores by using anti-CENPC antibodies. In contrast, the high grade and dedifferentiated liposarcomas showed a different pattern. In 2 cases, amplified chromosome 12 sequences, including amplification of alpha-satellite 12 sequences in 1 case, were present on chromosomes with typical centromeres. In another case, the rings were similar to WDLPS-ALP rings, but a large marker contained a chromosome 5 centromere and amplified alpha-satellite sequences from chromosome 8. ALP-WDLPS is the first example of a tumor class for which the presence of stable analphoid chromosomes is a constant and specific abnormality. Formation of newly derived centromeres, so-called neocentromeres, could be an original and effective way to maintain a selective advantage in neoplastic cells by conferring stability to the supernumerary chromosomes of ALP-WDLPS. The activation of normally non-centromeric sequences might be obtained by an epigenetic mechanism due to the peculiar chromatin conformation of these highly complex chromosomes.
Blotting, Southern↗
Multiple small accessory marker chromosomes from different centromeric origin in a moderately mentally retarded male.
The occurrence of more than two small accessory chromosomes (SACs) in a single individual is extremely rare. Here, we characterize six SACs found in the cells of two different tissues of a moderately mentally retarded male. Microdissection combined with regular FISH demonstrates that the SACs are ring chromosomes derived from the centromeres of different chromosomes. The SACs are often associated with the centromeres of other chromosomes. Immunofluorescence with an anti-CENP-C antibody demonstrates that the SACs contain an active centromere. A possible mechanism by which the SACs originated and their clinical relevance are discussed.
Centromere↗
Identification of multiple copies of a 20q-chromosome in a case of myelodysplastic syndrome: a FISH study.
In myelodysplastic syndromes (MDS) karyotypic aberrations identify subgroups of patients with distinct clinical-morphological features and can be relevant in risk assessment of developing leukemia. Often conventional cytogenetic analysis is not sufficiently informative due to the presence of partially or completely unrecognizable chromosome markers. By chromosome microdissection (MD) and fluorescence in situ hybridization (FISH) we investigated the nature of a karyotypic marker occurring in multiple copies in one case of MDS arisen in a patient previously treated for breast cancer. Results showed dicentrics derived from telomeric fusion between interstitially deleted 20q-chromosomes. The abnormal karyotype resulted into polysomy for a deleted chromosome 20q.
Aged↗
Delineation of the critical deletion region for congenital heart defects, on chromosome 8p23.1.
Deletions in the distal region of chromosome 8p (del8p) are associated with congenital heart malformations. Other major manifestations include microcephaly, intrauterine growth retardation, mental retardation, and a characteristic hyperactive, impulsive behavior. We studied genotype-phenotype correlations in nine unrelated patients with a de novo del8p, by using the combination of classic cytogenetics, FISH, and the analysis of polymorphic DNA markers. With the exception of one large terminal deletion, all deletions were interstitial. In five patients, a commonly deleted region of approximately 6 Mb was present, with breakpoints clustering in the same regions. One patient without a heart defect or microcephaly but with mild mental retardation and characteristic behavior had a smaller deletion within this commonly deleted region. Two patients without a heart defect had a more proximal interstitial deletion that did not overlap with the commonly deleted region. Taken together, these data allowed us to define the critical deletion regions for the major features of a del8p.
Abnormalities, Multiple↗
A mosaic extra ring chromosome 4 in a female patient with postnatal overgrowth.
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Child, Preschool↗
Conserved DNA sequences adjacent to chromosome fragmentation and telomere addition sites in Euplotes crassus.
During the formation of a new macronucleus in the ciliate Euplotes crassus, micronuclear chromosomes are reproducibly broken at approximately 10 000 sites. This chromosome fragmentation process is tightly coupled with de novo telomere synthesis by the telomerase ribonucleoprotein complex, generating short linear macronuclear DNA molecules. In this study, the sequences of 58 macronuclear DNA termini and eight regions of the micronuclear genome containing chromosome fragmentation/telomere addition sites were determined. Through a statistically based analysis of these data, along with previously published sequences, we have defined a 10 bp conserved sequence element (E-Cbs, 5'-HATTGAAaHH-3', H = A, C or T) near chromosome fragmentation sites. The E-Cbs typically resides within the DNA destined to form a macronuclear DNA molecule, but can also reside within flanking micronuclear DNA that is eliminated during macronuclear development. The location of the E-Cbs in macronuclear-destined versus flanking micronuclear DNA leads us to propose a model of chromosome fragmentation that involves a 6 bp staggered cut in the chromosome. The identification of adjacent macronuclear-destined sequences that overlap by 6 bp provides support for the model. Finally, our data provide evidence that telomerase is able to differentiate between newly generated ends that contain partial telomeric repeats and those that do not in vivo.
Animals↗
Noonan-like phenotype in monozygotic twins with a duplication-deficiency of the long arm of chromosome 18 resulting from a maternal paracentric inversion.
We report on newborn monozygotic twins with a Noonan-like phenotype, and multiple congenital anomalies due to a monocentric recombinant chromosome 18. The mother carried a paracentric inversion of the long arm of chromosome 18, inv(18)(q21.1q22.3). Cytogenetic, fluorescent in situ hybridization, comparative genomic hybridization and DNA marker analyses allowed the delineation of the deleted (18q22.3-qter) and duplicated (18q12.1-q21.1) chromosomal regions in the recombinant chromosome 18, and suggest that this duplication-deletion chromosome 18 resulted from breakage of a dicentric recombinant chromosome 18 with subsequent reconstitution of telomeric sequences on the long arm. Marked variability is observed in the phenotypic expression of the same chromosomal anomaly in these monozygotic twins. The clinical findings of these patients are compared with those reported in proximal 18q-duplication and distal 18q-deletion patients. The clinical features of both infants are compatible with Noonan syndrome, suggesting that a locus for this syndrome may be located on the long arm of chromosome 18.
Chromosome Deletion↗
Chromosome healing of constitutional chromosome deletions studied by microdissection.
Broken chromosomes are highly unstable and are subject to chromosome fusion or loss. As an exception, healing of human chromosomes occurs which can lead to constitutional or acquired terminal chromosome deletion disorders. Both de novo telomere addition at the breakpoint and telomere capture have been implicated as healing mechanisms. We investigated the origin of the novel ends of chromosomes 4p and 5p in a patient with the Wolf-Hirschhorn syndrome and in 4 patients with the Cri-du-Chat syndrome by chromosome microdissection. Our results suggest that de novo telomere synthesis by telomerase is the main mechanism of chromosome healing in constitutional chromosome deletions.
Abnormalities, Multiple↗
Unusual de novo t(13;15)(q12.1;p13) translocation leading to complex mosaicism including jumping translocation.
We report on a patient with neurosensory deafness, cataract and moderate mental retardation showing a constitutional mosaicism with the predominant cell line consisting of a 45,XY,-13,-15,+t(13;15) translocation of the Robertsonian type. By means of fluorescence in situ hybridization (FISH) using a panel of acrocentric pericentromeric probes and various banding techniques, the breakpoints in the translocation were determined at 13q12.1 and 15p13 respectively. Five other cell lines were present, at low percentage, one of them showing a t(13;15) tandem translocation. Interstitial telomeric sequences could be detected at the translocation fusion sites in both the Robertsonian and tandem translocations. The mosaicism appears therefore to be a consequence of chromosomal instability involving the t(13;15) fusion region of the predominant cell line, and related to the presence of interstitial telomeric sequences. The present observation suggests that in the pericentromeric 13q12 region, a gene involved in neurosensory deafness may be located.
Cataract↗
Localization by FISH of centric fission breakpoints in a de novo trisomy 9p patient with i(9p) and t(9q;11p).
Localization by FISH of centric fission breakpoints in a de novo trisomy 9p patient with i(9p) and t(9q;11p): In this report we present a 38 year-old, severely mentally retarded female with 9p trisomy due to isochromosome 9p, i(9p), formation and translocation of the long arm of the rearranged chromosome 9 onto the telomere region of the short arm of chromosome 11: karyotype: 46, XX, -9, -11, +i(9p), +der(11) t(9;11) (q12;p15.5). C-banding showed that the i(9p) was monocentric and that der(11) had an additional C-band at the t(9q;11p) junction. The centric rearrangements were further identified by fluorescence in situ hybridisation (FISH) using a panel of chromosome 9 (peri)centric DNA probes. Analysis with probe pG-Xbal 1/340 (locus D4Z1), detecting the satellite subfamily at the centromeres of chromosomes 4 and 9, revealed small signals at the primary constriction of i(9p) but no signals at the breakpoint junction of the t(9q;11p). Further analysis using respectively chromosome 9 classical satellite probe (locus D9Z1), that consists of beta satellite sequences and pHuR98 probe (locus D9Z3) which detects satellite 3 DNA, localized to the 9qh region, both revealed translocation of these DNA sequences to the breakpoint of the t(9;11) junction. By using a 3'biotinylated oligonucleotide (TTAGGG)7 probe, no evidence was found for the presence of interstitial telomeric repeats at the t(9q;11p) breakpoint junction indicating that this derivative chromosome is the result of a reciprocal translocation with loss of telomeric regions including terminal 11p15.5-->pter. Our results provide evidence that the misdivision process that occurs on the chromosome 9 centric region results either from breakage in the alphoid DNA arrays or at the junction between alphoid and DNA regions.
Adult↗
The human peroxisomal multifunctional protein involved in bile acid synthesis: activity measurement, deficiency in Zellweger syndrome and chromosome mapping.
The dehydrogenation of 24R,25R-varanoyl-CoA, the physiological intermediate formed during the peroxisomal breakdown of the bile acid intermediate trihydroxycoprostanic acid, was studied in human liver. The reaction appeared to be catalyzed by two different enzymes. A first one, present in the cytosol, did not discriminate between the four possible varanoyl-CoA isomers and did not require the CoA moiety. The second enzymic activity was associated with peroxisomes and acted only on the 24R,25R-isomer, in which the 24-hydroxy group possesses the D-configuration. The D-specific dehydrogenase is part of a 79 kDa protein which represents the human counterpart of a recently discovered second multifunctional protein in rat liver peroxisomes, named multifunctional protein 2 (MFP-2). Human MFP-2, like its rat counterpart, is also responsible for the formation (by hydratation) of 24R,25R-varanoyl-CoA. A deficiency of MFP-2 in Zellweger liver could be demonstrated immunologically by using antibodies against the rat enzyme and enzymically -- after removal of the cytosol -- by using 24R,25R-varanoyl-CoA. The gene coding for MFP-2 was mapped to chromosome 5q2.3.
3-Hydroxyacyl CoA Dehydrogenases↗
Interstitial telomeric sequences at the junction site of a jumping translocation.
The mechanism(s) for the origin of jumping translocations (JTs) are unknown. To assess the possible involvement of telomeric sequences in the jumping process, metaphases of a patient with hydrops fetalis having a JT were analyzed for the presence of interstitial telomeres. Telomere DNA sequences were detected at the junction sites of the donor and the recipient chromosomes. Interstitial telomeric sequences have so far only been detected in JTs involving chromosome 15q in patients with Prader-Willi syndrome. Our finding of interstitial telomeric sequences in a JT with a chromosome different from chromosome arm 15q in a patient without Prader-Willi syndrome implies that telomere sequences may be common to all telomeric JTs. The possible role of telomeric sequences as a cause of the observed chromosomal mosaicism is discussed.
Chromosomes, Human, Pair 4↗