Subject(s)
Nucleic Acids/genetics , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, Steroid/genetics , Alleles , Fluorescence Resonance Energy Transfer , Fluorescent Dyes , Genotype , Humans , Polymorphism, Genetic/genetics , Pregnane X Receptor , Reverse Transcriptase Polymerase Chain Reaction , TemperatureABSTRACT
We report on a patient presenting with mental retardation and obesity and a proximal duplication of chromosome 15. The patient shared some clinical signs with Prader-Willi syndrome. With a region-specific paint, generated by microdissection, a duplication in region 15q11.2-q13 was shown to be present. Subsequently, FISH with probes localized to chromosome region 15q11.2-q12 and microsatellite analysis was used to characterize this chromosome aberration further and an insertion duplication within the region frequently deleted in Prader-Willi and Angelman syndrome was demonstrated.
Subject(s)
Chromosomes, Human, Pair 15/genetics , Gene Duplication , In Situ Hybridization, Fluorescence/methods , Prader-Willi Syndrome/genetics , Child , Chromosome Aberrations/genetics , Chromosome Disorders , DNA Methylation , DNA Probes/genetics , Electrophoresis, Agar Gel , Gene Deletion , Genetic Markers , Humans , Karyotyping , Male , Microsatellite Repeats/genetics , Polymerase Chain ReactionABSTRACT
We report on a patient with a de novo translocation between the long arms of chromosomes 14 and 18. The translocation was studied using microdissection in combination with fluorescence in situ hybridization (micro-FISH). Five copies of the chromosomes involved in the translocation were isolated by microdissection and amplified by means of degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR). Reverse chromosome painting with the biotin-labeled PCR product showed that part of the q-arm of chromosome 18 had no signal. The deletion was characterized further by FISH with band-specific probes and it was concluded that the rearrangement was unbalanced: 46,XY,t(14;18)(14pter-->14q22::18q21.1-->18qter) (18pter-->18q12.2::14q22-->14qter). The patient, who presented with psychomotor retardation, mild obesity, pes equinovarus, strabismus, and facial anomalies, is compared with previously reported patients with an interstitial deletion of band 18q12.
Subject(s)
Chromosomes, Human, Pair 14/genetics , Chromosomes, Human, Pair 18/genetics , Translocation, Genetic/genetics , Child, Preschool , DNA Probes , Gene Deletion , Humans , In Situ Hybridization, Fluorescence , Intellectual Disability/genetics , Karyotyping , MaleABSTRACT
Microdissection and fluorescence in situ hybridisation (FISH) were used to elucidate the nature of a complex chromosome translocation, after GTG banding failed in the complete characterisation of the structural rearrangement between chromosomes 6 and 12. These chromosomes were painted with chromosome specific paints and one of the chromosome regions involved in the translocation was isolated by microdissection. Ten copies of the microdissected region were collected with microneedles from GTG banded metaphases, transferred to a collecting drop, and amplified by means of DOP-PCR. The PCR product was labelled with biotin-14-dATP and used as a FISH probe for hybridisation to normal metaphase chromosomes and metaphase chromosomes of the patients (microFISH). FISH with this chromosome region specific painting probe and with chromosome band specific probes enabled the characterisation of a complex chromosome rearrangement with five breakpoints in two chromosomes. This resulted in the following karyotype: 46,XY,t(6;12)(6pter--> 6q12::12q24.1-->12qter;12qter-->12q13.3:: 6q16.2-->6q26::12q13.3-->12q24.1::6q12--> 6q16.2::6q26-->6qter).
Subject(s)
Chromosome Breakage/genetics , Adolescent , Chromosome Banding , Chromosomes, Human, Pair 12 , Chromosomes, Human, Pair 6 , Cytogenetics , DNA Probes , Humans , In Situ Hybridization, Fluorescence , Karyotyping , Male , Metaphase/genetics , Polymerase Chain ReactionABSTRACT
Micro-FISH was used to elucidate the chromosomal origin of marker chromosomes in three patients. Ten copies of marker chromosomes were collected with microneedles from GTG banded metaphases, transferred to a collecting drop and amplified by means of DOP-PCR. The PCR products were labeled with biotin-14-dATP and used as FISH probes for hybridization to normal metaphase chromosomes and to metaphase chromosomes of the patients (reverse painting). With the generation of chromosome region-specific painting probes by PCR amplification of microdissected DNA and subsequent FISH it was possible to identify the marker chromosomes in all patients. One marker appeared to be derived from the centromere region of the X-chromosome and the proximal third of the long arm, one from the centromere region of chromosome 17 and one marker chromosome was identified as an isochromosome 18p.
Subject(s)
Chromosome Aberrations , Chromosome Disorders , In Situ Hybridization, Fluorescence/methods , Polymerase Chain Reaction/methods , Adult , Child , Child, Preschool , Female , HumansABSTRACT
Microdissection combined with fluorescence in situ hybridization (micro-FISH) was used to visualize deletions in rearranged human chromosomes and in a de novo translocation. In each experiment five copies of a structurally aberrant chromosome or of the two chromosomes involved in the de novo translocation were isolated by microdissection and amplified using DOP-PCR. The PCR products were then used as probes for FISH to metaphase chromosomes of three patients. After reverse chromosome painting, the structurally aberrant chromosomes were completely painted, and the region deleted in the aberrant chromosomes was visible in the normal chromosomes. The smallest deletion that could be demonstrated this way was a microdeletion of approximately 6 x 10(6) bp, which is frequently reported in Angelman and Prader-Willi syndromes.
Subject(s)
Chromosome Deletion , In Situ Hybridization, Fluorescence/methods , Translocation, Genetic , Child , Child, Preschool , Chromosome Banding , Chromosomes, Human, Pair 14 , Chromosomes, Human, Pair 15 , Chromosomes, Human, Pair 18 , Chromosomes, Human, Pair 3 , Female , Fluorescent Dyes , Humans , Indoles , Infant, Newborn , Male , Polymerase Chain ReactionABSTRACT
We report on 2 girls with mosaic tetrasomy 8p. Patient 1 showed the extra iso 8p chromosome in 20% of cultured lymphocytes and 18% of cultured fibroblasts [46,XX/47,XX,+i(8p)]. She presented with growth retardation, mild facial alterations, and motor developmental delay. Patient 2 presented with developmental delay, hypotonia, and slight facial alterations; she had the extra iso 8p chromosome in 94% of cultured peripheral lymphocytes. The patients are compared to the 6 previously reported cases. In our experience, the presently reported patients clinically resemble children with inv dup(8)(p21-p22) and patients with mosaic trisomy 8.
Subject(s)
Abnormalities, Multiple/genetics , Aneuploidy , Chromosomes, Human, Pair 8 , Developmental Disabilities/genetics , Mosaicism , Chromosome Banding , Chromosome Inversion , Face/abnormalities , Female , Humans , Infant , Karyotyping , Muscle Hypotonia/geneticsABSTRACT
Fluorescent in situ hybridization with probes specific for a chromosomal subregion and chromosome-specific libraries (chromosome painting) are important new methods for assessing chromosome rearrangements. In this paper we present four patients with additional chromosomal material on chromosome 8p who have been studied using G-banding techniques, chromosome painting and FISH with cosmid probes specific for the region 8p23.1-->8pter. In all cases we found a partial inversion duplication of 8p along with a deletion of the region 8p23.1-->8pter.
