Yueh-Chun Li

Molecular cytogenetic analysis of de novo dup(5)(q35.2q35.3) and review of the literature of pure partial trisomy 5q

An 11‐year‐old girl presented with the phenotype of microcephaly, moderate mental retardation, motor retardation, short stature, strabismus, brachydactyly, and facial dysmorphism. She had undergone surgery for inguinal hernias. Detailed examinations of the heart and other internal organs revealed normal findings. Her karyotype was 46,XX,dup(5)(q35.2q35.3) de novo. Molecular cytogenetic analysis showed a paternally derived 5q35.2 → q35.3 direct duplication and led to a correlation between the particular genotype and phenotype. This is the first description of a direct duplication of 5q35.2 → q35.3. Our case represents the smallest distal duplication of chromosome 5q that is not associated with congenital heart defects. Our case also represents the smallest distal duplication of chromosome 5q that is associated with short stature and microcephaly. Mutations or deletions of the NSD1 gene, mapped to 5q35.2 → q35.3, has been known to cause Sotos syndrome with cerebral gigantism, macrocephaly, advanced bone age and overgrowth. Our case provides evidence that the gene dosage effect of the NSD1 gene causes a reversed phenotype of microcephaly and short stature.

Sumoylation of p45/NF-E2: Nuclear Positioning and Transcriptional Activation of the Mammalian β-Like Globin Gene Locus

ABSTRACT NF-E2 is a transcription activator for the regulation of a number of erythroid- and megakaryocytic lineage-specific genes. Here we present evidence that the large subunit of mammalian NF-E2, p45, is sumoylated in vivo in human erythroid K562 cells and in mouse fetal liver. By in vitro sumoylation reaction and DNA transfection experiments, we show that the sumoylation occurs at lysine 368 (K368) of human p45/NF-E2. Furthermore, p45 sumoylation enhances the transactivation capability of NF-E2, and this is accompanied by an increase of the NF-E2 DNA binding affinity. More interestingly, we have found that in K562 cells, the β-globin gene loci in the euchromatin regions are predominantly colocalized with the nuclear bodies promyelocytic leukemia protein (PML) oncogenic domains that are enriched with the PML, SUMO-1, RNA polymerase II, and sumoylatable p45/NF-E2. Chromatin immunoprecipitation assays further showed that the intact sumoylation site of p45/NF-E2 is required for its binding to the DNase I-hypersensitive sites of the β-globin locus control region. Finally, we demonstrated by stable transfection assay that only the wild-type p45, but not its mutant form p45 (K368R), could efficiently rescue β-globin gene expression in the p45-null, erythroid cell line CB3. These data together point to a model of mammalian β-like globin gene activation by sumoylated p45/NF-E2 in erythroid cells.

A paternally derived inverted duplication of distal 14q with a terminal 14q deletion

A girl presented with a phenotype including neonatal hypotonia, psychomotor retardation, mental retardation, short stature, and facial dysmorphism. She demonstrated common features of both 14q31‐qter duplication and terminal 14q deletion. She had undergone surgery for patent ductus arteriosus and pyloric stenosis in infancy. Her karyotype was 46,XX,der(14) dup(14)(q32.3 q31.3)del(14)(q32.3). Molecular cytogenetic analysis showed a paternally derived 14q31.3‐q32.3 duplication and a terminal 14q deletion and led to the correlations between a particular genotype and phenotype. This is the first description of a deletion and inverted duplication of 14q, and adds 14q to the growing list of the inverted duplication associated with a terminal deletion.

Genomic Alterations in Human Malignant Glioma Cells Associate with the Cell Resistance to the Combination Treatment with Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand and Chemotherapy

Purpose: Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) is currently under clinical development as a cancer therapeutic agent. Many human malignant glioma cells, however, are resistant to TRAIL treatment. We, therefore, investigated the genomic alterations in TRAIL-resistant malignant glioma cells. Experimental Design: Seven glioma cell lines and two primary cultures were first analyzed for their sensitivity to TRAIL and chemotherapy and then examined for the genomic alterations in key TRAIL apoptotic genes by comparative genomic hybridization (CGH), G-banding/spectral karyotyping, and fluorescence in situ hybridization (FISH). Results: CGH detected loss of the chromosomal regions that contain the following genes: 8p12-p23 (DR4 and DR5), 2q33-34 (caspase-8), 11q13.3 (FADD), 22q11.2 (Bid), and 12q24.1-q24.3 (Smac/DIABLO) in TRAIL-resistant cell lines. Spectral karyotyping showed numerical and structural aberrations involving the chromosomal regions harboring these genes. A combination of G-banding/spectral karyotyping and FISH further defined the loss or gain of gene copy of these genes and further showed the simultaneous loss of one copy of DR4/DR5, caspase-8, Bid, and Smac in two near-triploid cell lines that were resistant to the combination treatment with TRAIL and chemotherapy. Loss of the caspase-8 locus was also detected in a primary culture in correlation with the culture resistance to the combined TRAIL and chemotherapy treatment. Conclusions: The study identifies chromosomal alterations in TRAIL apoptotic genes in the glioma cells that are resistant to the treatment with TRAIL and chemotherapy. These genetic alterations could be used to predict the responsiveness of malignant gliomas to TRAIL-based therapies in clinical treatment of the tumors.

Small supernumerary marker chromosome originating from chromosome 10 associated with an apparently normal phenotype

Small supernumerary marker chromosomes (sSMC) originating from chromosome 10 are rare. Only seven cases have been documented, and among those three cases were diagnosed prenatally. We reported on another prenatal diagnosis of a de novo mosaic sSMC in an apparently normal female fetus whose mother had conceived with assisted reproductive technology (ART) procedures. G‐banding analysis of amniotic cells was performed. Spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH) studies with chromosome 10‐specific alphoid satellite DNA probe were used to identify the chromosome 10 origin of the sSMC. Further FISH study with telomeric sequence probes showed that the sSMC lacked a hybridization signal, suggesting that the marker could be a ring chromosome. FISH studies using BAC clone probes specific for the regions within 10p11.2, 10q11.1, and 10q11.2 showed that the short arm breakpoint was located between 29.8 and 30.7 Mb from the 10p telomere, and that the long arm breakpoint was located less than 43.6 Mb from the 10p telomere. The karyotype of the fetus was 47,XX,+mar. ish der(10)(SKY+ CEP 10+, CTD‐2130I7+, RP11‐89J23−)/46,XX. Oligonucleotide microarray‐based copy number variations (CNV) analysis was also performed and showed a 6.7 Mb duplication from 10p11.2 to 10q11.2 (36.2–42.9 Mb) with Affymetrix SNP‐array 6.0 genotype: arr cgh. 10p11.2q11.2(CN_519687 → CN_541524) X 3. At the 1‐year follow‐up, the baby did not have any findings of the trisomy 10p syndrome. This observation provided further credence to the concept that additional chromosome material of proximal 10p11.2 may not contribute to the trisomy 10p syndrome phenotype.

Chromosomal distribution and organization of three cervid satellite DNAs in Chinese water deer (Hydropotes inermis)

The species-specific profile and centromeric heterochromatin localization of satellite DNA in mammalian genomes imply that satellite DNA may play an important role in mammalian karyotype evolution and speciation. A satellite III DNA family, CCsatIII was thought to be specific to roe deer (Capreolus capreolus). In this study, however, this satellite DNA family was found also to exist in Chinese water deer (Hydropotes inermis) by PCR-Southern screening. A satellite III DNA element of this species was then generated from PCR-cloning by amplifying this satellite element using primer sequences from the roe deer satellite III clone (CCsatIII). The newly generated satellite III DNA along with previously obtained satellite I and II DNA clones were used as probes for FISH studies to investigate the genomic distribution and organization of these three satellite DNA families in centromeric heterochromatin regions of Chinese water deer chromosomes. Satellite I and II DNA were observed in the pericentric/centric regions of all chromosomes, whereas satellite III was distributed on 38 out of 70 chromosomes. The distribution and orientation of satellite DNAs I, II and III in the centromeric heterochromatin regions of the genome were further classified into four different types. The existence of a Capreolus-like satellite III in Chinese water deer implies that satellite III is not specific to the genus Capreolus (Buntjer et al., 1998) and supports the molecular phylogeny classification of Randi et al. (1998) which suggests that Chinese water deer and roe deer are closely related.

A new familial insertion, ins(18;9)(q12.2;q33.1q31.1) with a 9q31.1-9q33.1 deletion in a girl with a cleft lip and palate.

A New Familial Insertion, ins(18;9)(q12.2;q33.1q31.1) With a 9q31.1–9q33.1 Deletion in a Girl With a Cleft Lip and Palate Shu-Chin Chien, Yueh-Chun Li, Ling-Hui Li, Jer-Yuarn Wu, Pei-Ching Hsu, Sue-Lin Shi, Fuu-Jen Tsai, and Chyi-Chyang Lin* Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung, Taiwan Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan Department of Medical Research, China Medical University Hospital, Taichung, Taiwan Department of Medical Genetics, China Medical University Hospital, Taichung, Taiwan Department of Pediatrics, China Medical University Hospital, Taichung, Taiwan Graduate Institute of Basic Medical Sciences, China Medical University, Taichung, Taiwan

Rare rearrangements: a "jumping satellite" in one family and autosomal location of the SRY gene in an XX male.

A satellited short arm of the Y chromosome (Yps) is rare. Only one de novo case of Yps has been documented. Here we report the prenatal diagnosis of Yps in a male fetus with a karyotype, 46,XYps. Family chromosome study showed that the father and a sister had a satellited short arm of the X chromosome (Xps). A phenotypically normal male child with the Yps was delivered. This is the first familial case showing a satellite “jumping” from Xp to Yp. We propose that it resulted from a crossover within the pseudoautosomal region 1 (PAR1) on the distal Xp and Yp during paternal meiosis. In addition to the rare translocation mentioned above, relocation of the SRY gene onto an autosome in XX males is also a rare event. Herein we report a phenotypically normal male fetus with a 46,XX karyotype. Fluorescence in situ hybridization (FISH) study showed that the SRY locus had been transferred to the terminal short arm of a chromosome 3. The terminal short arm deletion of this chromosome 3 was also confirmed by FISH study with a subtelomeric probe and the breakpoint of the terminal deletion was estimated between 446 and 664 kb from the 3p telomere by real‐time qPCR study with a gene sequence and STS markers in this region. A healthy boy was delivered at 37 weeks of gestation. At 1‐year follow‐up, the childs growth pattern and development were appropriate for age.

Prenatal detection and characterization of a psu idic(8)(p23.3) which likely derived from nonallelic homologous recombination between two MYOM2-repeats

Mosaicism with an isodicentric 8 with a breakpoint at p23.3 [idic(8)(p23.3)] is very rare. We report the first prenatal case on a male fetus, in which obstetric ultrasound revealed multiple congenital anomalies at 28 weeks of gestation. Cytogenetic analysis of amniocytes showed mos 45,XY,-8,psu idic(8)(p23.3)[16]/46,XY,psu idic(8)(p23.3)[4], and that of cord blood lymphocytes revealed mos 46,XY, psu idic(8)(p23.3)[37]/45,XY,-8,psu idic(8)(p23.3)[13]. Fluorescence in situ hybridization studies revealed that the break-reunion occurred at the cytoband 8p23.3 within the physical position 2.08 Mb from the 8p telomere. Chromosomal microarray analyses further assigned the duplication/deletion breakpoint at 2.16 Mb (Agilent 244K) and at 2.19 Mb (Affymetrix SNP6.0). Analysis of microsatellite DNA indicated that the psu idic(8)(p23.3) was derived from the maternal chromosome 8. Together, these findings indicate that the fetus was nullisomic for ~2.2 Mb from 8pter, trisomic for the rest of chromosome 8 in mosaic condition, and likely had breaks in MYOM2 repeats of the maternal chromosome 8.

Partial Trisomy 3p and Monosomy 7p Associated with Tetralogy of Fallot and Infantile Seizure

A 7-month-old female infant was referred because of hypothyroidism, seizure, respiratory distress syndrome, and tetralogy of Fallot (TOF) with hypoxic spell. Her father and 24-year-old mother were healthy and nonconsanguineous. There was no family history of congenital malformations. The mother denied any exposure to alcohol, teratogenic agents or infectious diseases during this pregnancy. She received regular prenatal examinations at a local clinic. The infant was born prematurely at 35 weeks of gestation. However, bradycardia, restlessness, cyanosis, gasping respiration, upgaze, and episodes of seizure developed soon after delivery. The infant’s external appearance was grossly normal, and the extremities were freely movable. The body weight was less than third percentile with growth restriction. Serial studies were arranged. Echocardiography revealed an atrial septal defect, a large ventricular septal defect, right ventricular hypertrophy, and severe pulmonary stenosis that were consistent with TOF. Brain sonography revealed moderate dilatation of lateral and third ventricles, in favor of the diagnosis of benign extracerebral fluid collection. Conventional cytogenetic studies performed on the