A boy is described, who shares many of the clinical features found in the few patients with a partial 17q trisomy known at present. Karyotyping revealed a de novo 17q+ chromosome, interpretable as a tandem duplication of the distal long arm region 17q25.Close

A child with a combined trisomy 15q11 and 17q25 shows the typical phenotype of partial duplication 17q. The male fetus developed in the 3rd trimenon of pregnancy a nonimmune hydrops fetalis (NIHF). Analysing the chromosomes of 54 cases with NIHF during the 2nd and 3rd trimenon and after birth we found chromosomal abnormalities in 33% of them.Close

An 18-month-old girl was found to have monosomy for 17q25—-qter which resulted from an unequal crossing-over in the mother carrying an apparently balanced translocation 46, XX, t(3;17) (p12;q24). Clinical features of the proband included: cleft palate, micrognathia and glossoptosis. It seems to be the first reported case where a single band deletion in the long arm of chromosome 17 has ever been noted.Close

We report a case with derivative chromosome 17 which could not be characterized by routine G-banding, since the additional material on 17q overlapped with chromosome bands 2q35 -->qter, 3p25-->pter, 4p15-->pter, 5q33-->qter, 7p15-->pter, 12p11.2-->pter, 14q24-->qter and 16q22-->qter. Therefore, whole chromosome paint and region specific probes were used to identify the abnormality by FISH-technique which revealed a 46,XY, der (17) t (4;17) (p15.2;q25) karyotype. The proband was partially trisomic for 4p15.2-->pter and monosomic for the distal 17q25-->qter regions. The major clinical features included: anti-mongoloid slanted palpebrae, coloboma of right iris, depressed nasal bridge, high arched palate, protruding tongue, micrognathia and small penis. The MRI of the brain revealed midly hypoplastic cerebellar vermis, and a normal septum pellucidum. The infant responded to therapy for hypoglycemia and was discharged under stable condition. Prior to cytogenetic evaluation the infant was not recognized as either "trisomy 4p syndrome" or "monosomy 17q syndrome".Close

Relative phylogenetic divergence of the members of the Pongidae family has been based on genetic evidence. The recent isolation of subtelomeric probes specific for human (HSA) chromosomes 1q, 11p, 13q, and 16q has prompted us to cross-hybridize these to the chromosomes of the chimpanzee (Pan troglodytes, PTR), gorilla (Gorilla gorilla, GGO), and orangutan (Pongo pygmaeus, PPY) to search for their equivalent locations in the great apes. Hybridization signals to the 1q subtelomeric DNA sequence probe were observed at the termini of human (HSA) 1q, PTR 1q, GGO 1q, PPY 1q, while the fluorescent signals to the 11p subtelomeric DNA sequence probe were observed at the termini of HSA 11p, PTR 9p, GGO 9p, and PPY 8p. Fluorescent signals to the 13q subtelomeric DNA sequence probe were observed at the termini of HSA 13q, PTR 14q, GGO 14q, and PPY 14q, and positive signals to the 16p subtelomeric DNA sequence probe were observed at the termini of HSA 16q, PTR 18q, GGO 17q, and PPY 19q. These findings apparently suggest sequence homology of these DNA families in the ape chromosomes. Obviously, analogous subtelomeric sequences exist in apes' chromosomes that apparently have been conserved through the course of differentiation of the hominoid species.Close

Defining boundaries of chromosomal rearrangements at the molecular level would benefit from landmarks that link the cytogenetic map to physical, genetic, and transcript maps, as well as from large-insert FISH probes for such loci to detect numerical and structural rearrangements in metaphase or interphase cells. Here, we determined the locations of 24 genetically mapped CEPH-Mega YACs along the FLpter scale (fractional length from p-telomere) by quantitative fluorescence in situ hybridization analysis. This generated a set of cytogenetically mapped probes for chromosome 17 with an average spacing of about 5 cM. We then developed large-insert YAC, BAC, PAC, or P1 clones to the following 24 known genes, and determined refined map locations along the same FLpter scale: pter-TP53-TOP3-cen-TNFAIP1-ERBB2-TOP2A-BRCA1- TCF11-NME1-HLF-ZNF147/CL N80-BCL5/MPO/SFRS1-TBX2-PECAM1-DDX5/PRKCA- ICAM2-GH1/PRKAR1A-GRB2-CDK3 /FKHL13-qter. Taken together, these 48 cytogenetically mapped large-insert probes provide tools for the molecular analysis of chromosome 17 rearrangements, such as mapping amplification, deletion, and translocation breakpoints in this chromosome, in cancer and other diseases.Close

Human chromosomes terminate with specialized telomeric structures including the simple tandem repeat (TTAGGG)n and additional complex subtelomeric repeats. Unique sequence DNA for each telomere is located 100-300 kilobases (kb) from the end of most chromosomes. A high concentration of genes and a number of candidate genes for recognizable syndromes are known to be present in telomeric regions. The human telomeric regions represent a major diagnostic challenge in clinical cytogenetics, because most of the terminal bands are G negative, and cryptic deletions and translocations in the telomeric regions are therefore difficult to detect by conventional cytogenetic methods. In fact, several submicroscopic chromosomal abnormalities in patients with undiagnosed mental retardation or multiple congenital anomalies have been identified by other molecular methods such as DNA polymorphism analysis. To improve the sensitivity for deletion detection and to determine whether such cryptic rearrangements represent a significant source of human pathology that has not been previously appreciated, it would be valuable to have specific FISH probes for all human telomeres. We report here the isolation and characterization of a complete set of specific FISH probes representing each human telomere. As most of these clones are at a known distance of within 100-300 kb from the end of the chromosome arm, this provides a 10-fold improvement in deletion detection sensitivity compared with high-resolution cytogenetics (2-3 Mb resolution). While testing these probes, we serendipitously identified a family with multiple members carrying a cryptic 1q;11p rearrangement in the balanced or unbalanced state.Close

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Telomere-specific clones are a valuable resource for the characterization of chromosomal rearrangements. We previously reported a first-generation set of human telomere probes consisting of 34 genomic clones, which were a known distance from the end of the chromosome ( approximately 300 kb), and 7 clones corresponding to the most distal markers on the integrated genetic/physical map (1p, 5p, 6p, 9p, 12p, 15q, and 20q). Subsequently, this resource has been optimized and completed: the size of the genomic clones has been expanded to a target size of 100-200 kb, which is optimal for use in genome-scanning methodologies, and additional probes for the remaining seven telomeres have been identified. For each clone we give an associated mapped sequence-tagged site and provide distances from the telomere estimated using a combination of fiberFISH, interphase FISH, sequence analysis, and radiation-hybrid mapping. This updated set of telomeric clones is an invaluable resource for clinical diagnosis and represents an important contribution to genetic and physical mapping efforts aimed at telomeric regions.Close

The recent spreading of a subtelomeric region at nine different human chromosome ends was characterized by a combination of segregation analyses, physical mapping, junction cloning, and FISH investigations. The events occurred very recently in human genome evolution as demonstrated by sequence analysis of different alleles and the single location of the ancestral site at chromosome 17qter in chimpanzee and orangutan. The domain successfully colonized most 1p, 5q, and 6q chromosome ends and is also present at a significant frequency of 6p, 7p, 8p, 11p, 15q, and 19p ends. On 6qter, the transposed domain is immediately distal to the highly conserved, single-copy gene PDCD2.Close