1/12. tetrasomy 9p due to an intrachromosomal triplication of 9p13-p22.To date, approximately 30 patients have been described with a tetrasomy 9p, all being caused by the presence of an isochromosome 9p. We now report on a 3-year-old boy with a de novo intrachromosomal triplication of 9p13-p22, resulting in partial tetrasomy 9p. We compared his phenotype with cases of tetrasomy 9p caused by the presence of an extra isochromosome 9p. He has facial anomalies similar to those of cases of tetrasomy 9p, central nervous system abnormalities, and severe psychomotor retardation but no other major congenital anomalies. fluorescence in situ hybridization with region-specific probes showed that the middle repeat of the triplicated part is inverted. Microsatellite analysis demonstrated an involvement of both paternal chromosome 9 homologues in the triplication. This is compatible with either unequal crossing over of three of the four chromatids in paternal meiosis I or with a double crossing over in meiosis I and II (or an early mitotic division).- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/12. A microdeletion syndrome due to a 3-Mb deletion on 19q13.2--diamond-Blackfan anemia associated with macrocephaly, hypotonia, and psychomotor retardation.We report on a boy with congenital pure red blood cell aplasia [diamond Blackfan anemia (DBA)] and severe congenital hypotonia, macrocephaly, hypertelorism, a broad and tall forehead, medial epicanthus, and facial hypotonia with mouth-breathing and drooling, an affable and out-going personality, and a general psychomotor retardation. These features show similarity to the phenotype of the X-linked FG syndrome. DBA was diagnosed at the age of 4 months, and the boy underwent treatment with transfusion and with prednisolone. He had a normal 46, XY karyotype, but fluorescence in situ hybridization (FISH) analysis to metaphase chromosomes revealed a 3-Mb deletion on 19q13.2. This chromosomal region has previously been linked to the DBA phenotype and one 19q13 microdeletion has been identified in a patient with DBA. This deletion coincides with the deletion reported here. We suggest that the complex phenotype of our patient, including both DBA and the associated features, represent a microdeletion syndrome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/12. Molecular cytogenetic studies in three patients with partial trisomy 2p, including CGH from paraffin-embedded tissue.We report on three cases of partial trisomy 2p in which the identification and exact localization of the duplicated chromosome segment was possible only by application of molecular cytogenetic techniques. These included fluorescence in situ hybridization by use of wcp2, N-myc, and subtelomeric 2p probes and comparative genomic hybridization with dna isolated from blood samples, frozen fetal tendon, and formalin fixed, paraffin-embedded fetal lung tissue. Two of the cases concerned fetuses of gestational week 20 and 24 with duplication of nonoverlapping terminal (2pter-->p24) and more proximal (2p25-->p23) segments and with distinctly different phenotypes. The third case was due to a de novo inverted duplication of 2p25-->p23, with loss of the subtelomeric region of 2p. This 53-month-old girl was a bloom syndrome carrier. The patient had prenatal growth failure, borderline microcephaly, dilated lateral horns of the cerebral ventricles, transient cortical blindness, myopia, muscle hypotonia, and dilatation of the left renal collecting system. Dermal cysts were found on the glabella, the soles of both feet, and the vocal cord, causing respiratory embarrassment. Previously reported cases of pure trisomy 2p are reviewed, in an attempt to correlate clinical findings to overlapping regions in 2p. These cases illustrate the effectiveness of molecular cytogenetic methods in resolving subtle chromosomal aberrations in order to coordinate more accurately a chromosome regionspecific phenotype.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
4/12. Clinical and molecular-cytogenetic studies in seven patients with ring chromosome 18.We report the results of detailed clinical and molecular-cytogenetic studies in seven patients with ring chromosome 18. Classical cytogenetics and fluorescence in situ hybridization (FISH) analysis with the chromosome 18 painting probe identified five non-mosaic and two complex mosaic 46,XX,dup(18)(p11.2)/47,XX,dup(18)(p11.2), r(18) and 46,XX,dup(18)(p11.32)/47,XX,dup(18)(p11.32), r(18) cases. FISH analysis was performed for precise characterization of the chromosome 18 breakpoints using chromosome 18-specific short-arm paint, centromeric, subtelomeric, and a panel of fifteen Alu- and DOP-PCR YAC probes. The breakpoints were assessed with an average resolution of approximately 2.2 Mb. In all r(18) chromosomes, the 18q terminal deletions ranging from 18q21.2 to 18q22.3 ( approximately 35 and 9 Mb, respectively) were found, whereas only in four cases could the loss of 18p material be demonstrated. In two cases the dup(18) chromosomes were identified as inv dup(18)(qter-->p11.32::q21.3-->qter) and inv dup(18)(qter-->p11.32::p11.32-->p11.1: :q21.3-->qter)pat, with no evidence of an 18p deletion. A novel inter-intrachromatid mechanism of formation of duplications and ring chromosomes is proposed. Although the effect of "ring instability syndrome" cannot be excluded, the phenotypes of our patients with characteristic features of 18q- and 18p- syndromes are compared and correlated with the analyzed genotypes. It has been observed that a short neck with absence of cardiac anomalies may be related to the deletion of the 18p material from the r(18) chromosome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/12. Deletion of chromosome region 18q21.1 --> 18q21.3 in a patient without clinical features of the 18q- phenotype.In a 16-month-old boy referred because of developmental delay and asymmetric motor development, chromosome analysis showed an aberrant chromosome 18 in all 25 metaphases examined. The chromosome aberration was initially interpreted either as an interstitial deletion of chromosome region 18q21.1 --> 18q21.3 or an unbalanced translocation involving the distal part of the long arm of chromosome 18. Chromosome microdissection in combination with fluorescence in situ hybridization demonstrated that the aberrant chromosome 18 had an interstitial deletion, the karyotype being: 46,XY,del(18)(q21.1q21.3). At age 27 months, his development was moderately retarded. He showed craniofacial asymmetry but no other anomalies. The clinical and cytogenetic findings are compared with previously reported patients with a terminal or interstitial deletion in the long arm of chromosome 18.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/12. Mosaic supernumerary inv dup(15) chromosome with four copies of the P gene in a boy with pigmentary dysplasia.association of the pink-eye-dilution gene (P) with hypopigmentation is seen in patients who have oculocutaneous albinism type 2 (OCA2) and prader-willi syndrome (PWS) or angelman syndrome (AS). However, it remains unknown whether duplication or amplification of the P gene causes hyperpigmentation. We previously reported a woman who had hyperpigmentation with a duplication of the proximal part of 15q, including the P gene. Here, we describe an additional patient with mosaicism of inv dup(15) and clinical manifestations of severe psychmoter retardation, epilepsy, and pigmentary dysplasia showing mottled and linear patterns of hyperpigmentation. His karyotype was 47,XY, idic(15)(pter-->q14::q14-->pter)[38]/46,XY[12] de novo. Chromosomal fluorescence in situ hybridization (FISH) showed six copies of the P gene. Therefore, his cutaneous mosaicism might be caused by the presence of both normal and hyperpigmented skin due to multicopies of the P gene.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/12. Xq chromosome duplication in males: clinical, cytogenetic and array CGH characterization of a new case and review.Males with duplications within the long arm of the x chromosome are rare and most cases are inherited from a maternal heterozygote. We report a male with a de novo Xq duplication and review of the literature. The proband was ascertained prenatally after an abnormal expanded alpha-fetoprotein (AFP) screen and abnormal ultrasound findings. Chromosome analysis on amniocyte and subsequent peripheral blood lymphocyte cultures showed a male karyotype containing additional material on the long arm of the x chromosome. fluorescence in situ hybridization with an x chromosome whole chromosome paint probe showed that the additional material was derived from the x chromosome, interpreted as a dup(X)(q13.3q24). Further characterization of the duplication by array CGH showed a duplication size between 30-44 Mb as determined by the map position of the flanking clones on the array, and refined the breakpoints of the duplicated region to Xq21.32 --> Xq25. At birth, the proband had multiple craniofacial abnormalities, musculoskeletal anomalies, bilateral cryptorchidism with scrotal hypoplasia, conductive hearing loss, and profound generalized hypotonia despite normal birthweight, length, and head circumference. Although data regarding Xq duplications in males are limited, a clear pattern of characteristic features can be discerned as illustrated in the present case and confirmed in our literature review. Mental, psychomotor and growth retardation, as well as, craniofacial anomalies, muscle hypotonia, hypoplastic genitalia, cryptorchidism, feeding difficulties, and endocrine dysfunction are all significant issues in these individuals.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
8/12. The new wolf-hirschhorn syndrome critical region (WHSCR-2): a description of a second case.The wolf-hirschhorn syndrome (WHS), is a well known contiguous gene syndrome characterized by microcephaly, hypertelorism, prominent glabella, epicanthal folds, cleft lip or palate, cardiac defects, growth and mental retardation and seizures. The currently accepted WHS critical region (WHSCR) is localized between the loci D4S166 and D4S3327, where a deletion seems to generate all the clinical manifestations of the syndrome. Here we present a patient with a subtelomeric deletion of 4p16.3 showing growth and psychomotor delay with a typical WHS facial appearance and two episodes of seizures in conjunction with fever. The high-resolution G-banded karyotype was normal. fluorescence in situ hybridization (FISH) with a set of cosmids from 4p16.3, showed that the deletion in this patient was from the D4S3327 to the telomere, enabling the size of the deletion to be estimated as 1.9 Mb, excluding the accepted WHSCR deletion. This patient supports the recent proposal by Zollino et al. [2003] that the critical region for WHS is located distally to the WHSCR between the loci D4S3327 and D4S98-D4S16, and it is called "WHSCR-2" [Zollino et al., 2003].- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
9/12. A novel 2.3 Mb microduplication of 12q24.21q24.23 detected by genome-wide tiling-path resolution array comparative genomic hybridization in a girl with syndromic mental retardation.We report on a female patient with severe mental retardation, dysmorphic features, deafness, spasticity, and behavioural problems in whom a 2.3 Mb duplication of 12q24.21q24.23 was detected by genome-wide tiling-path resolution array-based comparative genomic hybridization. Mental retardation, microcephaly, short stature, recurrent infections, hypotonia and facial features, such as hypertelorism, epicanthal folds, and a broad nasal bridge, were also described in patients with larger duplications overlapping the 12q24.21q24.23 region. The duplicated region contains 16 genes, of which several genes, such as thyroid hormone receptor associated protein 2, replication factor C5 and nitric oxide synthase 1, are expressed in the brain and/or are involved in embryogenesis. The current case shows that microduplications might be a more frequent cause of mental retardation and human malformation than previously appreciated.- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |
10/12. Interstitial deletion of the long arm of chromosome 6.A de novo interstitial deletion of 6q21 was observed in a male baby with moderate microcephaly, facial dysmorphism, and psychomotor retardation. in situ hybridization with a c-myb probe showed that the gene was conserved on the deleted chromosome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
| | Next -> |