A whole exome sequencing study of a Korean proband with idiopathic basal ganglia calcification and its daughter.

Idiopathic basal ganglia calcification (IBGC) is characterized by brain calcification and a wide variety of neurological and psychiatric symptoms. In families displaying an autosomal dominant inheritance pattern, three causative genes have been identified: SLC20A2, PDGFRB, and very recently, PDGFB. While in clinical practice sporadic presentation of IBGC is frequent, well-documented reports of true sporadic occurrences are rare. We report a case of a 61-year-old woman who presented with depressive and dystonic symptoms revealing IBGC. Her 41-year-old daughter was healthy. In the proband, we identified 4 mutations in PDGFB, and 1 exonic mutation in SLC20A2, all of which were absent in the daughter. These mutations may result in a loss-of-function of PDGF-B or SLC20A2, which has been shown to cause IBGC in humans and disrupts the blood-brain barrier in mice resulting in brain calcification. Herein, we present the occurrence of a sporadic patient of IBGC and its causative mutations.

Molecular and clinicopathological analysis of dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) is a dermal and subcutaneous tumor of intermediate malignancy. The most remarkable cytogenetic feature of DFSP is the chromosomal translocation t(17;22)(q22;q13), causing a fusion of the platelet-derived growth factor beta chain (PDGFB) gene at 22q13, and the collagen type 1 alpha 1 (COL1A1) at 17q22. The aim of the study was to analyze the molecular characteristic of DFSP in conjunction with histopathological and clinical features. We performed fluorescence in situ hybridization (FISH) and multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) to detect chromosomal translocations and fusion gene transcripts in 16 formalin-fixed, paraffin-embedded DFSP samples. In addition, the amplification of PDGFB was also evaluated in the 16 DFSP samples by real-time PCR. FISH analysis revealed that all the 16 samples exhibited COL1A1-PDGFB gene fusion. Eleven out of 11 informative cases (100%) showed fusion transcripts by multiplex RT-PCR analysis. Various exons of the COL1A1 gene were fused with the PDGFB gene. Among them, exon 25 was found to be more frequently involved. Real-time PCR showed that the PDGFB copy number increase in the DFSP samples was higher than in normal skin tissues (p=0.007). Values of FISH fusion signals and PDGFB DNA analysis were variable between samples, but suggested that increased values might be associated with parameters of tumor progression. Our results confirm that analysis of the COL1A1-PDGFB status by FISH and RT-PCR is a useful tool in the confirmation of a DFSP diagnosis. In addition, the analysis of PDGFB copy number status may become a useful diagnostic marker since the gene is a potential target for treatment of DFSP patients.

Gene mutation analysis in five cases of dermatofibrosarcoma protuberans using formalin-fixed, paraffin-embedded tissues.

Fusion of the collagen type I a 1 (COL1A1) gene with the platelet-derived growth factor B-chain (PDGFB) gene has been pointed out in dermatofibrosarcoma protuberans. Various exons of the COL1A1 gene have been shown to be involved in the fusion with exon 2 of the PDGFB gene. We studied the breakpoints of the COL1A1 gene using formalin-fixed, paraffin-embedded tumour specimens from five patients with dermatofibrosarcoma protuberans (three reconfirmations and two new cases). Reverse transcriptase-PCR was performed using paraffin-embedded tissues. Nucleotide sequence analysis was carried out using the PCR products to identify the breakpoints. The COL1A1-PDGFB fusion transcripts were detected from the tumour specimens. Sequence analysis revealed that the ends of exons 18, 29, 38, 42 and 44 in the COL1A1 gene were fused with the start of exon 2 in the PDGFB. This study identified a novel COL1A1 breakpoint, namely, exon 44 of the COL1A1 gene. Detection of the aberrant fusion transcript using formalin-fixed, paraffin-embedded tumour specimens is useful as a diagnostic aid for dermatofibrosarcoma protuberans in cases where fresh or frozen samples of tumour tissue are not available.

Disruption of the PDGFB gene in a 1;22 translocation patient does not cause Costello syndrome.

We studied a female patient initially diagnosed with Costello syndrome who carries an apparently balanced translocation, t(1;22) (q24.3;q13.1). Molecular characterization of the translocation revealed a mosaic of two derivative chromosomes 1 in her peripheral blood lymphocytes, in one of which the coding region of the platelet-derived growth factor (PDGFB; chromosome 22q13.1) gene was disrupted. Both the initial translocation and the secondary intrachromosomal rearrangement appear to have occurred by nonhomologous (illegitimate) recombination. In 18 patients with Costello syndrome, mutation analysis of the genes belonging to the PDGF/R family, PDGFA, PDGFB, PDGFC, PDGFD, PDGFRA, and PDGFRB, revealed no pathogenic mutations. Reevaluation of the clinical symptoms of the translocation patient challenges the diagnosis of Costello syndrome in this patient. In total RNA isolated from lymphocytes of the translocation patient, we identified four different fusion transcripts consisting of PDGFB exons and parts of chromosome 1q24.3. In two of the mRNAs, exon 6 of PDGFB, encoding the 41 C-terminal amino acid residues, was absent. Immunofluorescence analysis showed that the wild-type protein was dispersed and formed a network-like structure in the extracellular matrix, whereas the two aberrant PDGFB proteins were localized in aggregates. We speculate that the biological consequences of the mutant PDGFB allele contributed to the unique disease phenotype of the translocation patient.

[Immortalized cell lines from murine embryos are characterized by progressive destabilization of their karyotype structure]. / Immortalizovannye linii kletok, poluchennye iz transgennykh émbrionov myshei, kharakterizuiutsia progressiruiushzchei destabilizatsiei struktury kariotipa.

The karyotype structure was studied for three cell lines obtained from cells of transgenic murine embryos at early stages of their establishment. The first line was obtained from a transgenic embryonic explantant containing oncogen v-sis under promotor MMTV, two other lines originated from cells of transgenic embryos containing oncogen k51. The karyotypic analysis of G-banded metaphase chromosomes revealed deviations from the normal mouse karyotype as early as by the third passage of cultivation of independent embryonic cell lines that contained a foreign oncogene in their genome. The repeated analysis that involved 15-22 passages revealed similar abnormalities: variability and progression in chromosome number with the appearance of hyperpolyploid combinations, and a large number of rearranged chromosomes, both marker and unique ones. It is concluded that introduction of a foreign oncogene into murine cell genome leads to its enhanced and progressive non-specific destabilization. Oncogen v-sis produces a more valuable karyotype destabilization than oncogen k51.

[Effect of truncated platelet-derived growth factor-alpha receptor on apoptosis and expression of c-sis mRNA of pulmonary artery smooth muscle cells].

OBJECTIVE: Platelet-derived growth factor (PDGF) plays an important role during the pathophysiological changes in vascular remodeling. The study aimed to investigate the effect of truncated PDGF-alpha receptor on apoptosis and expression of c-sis mRNA of pulmonary artery smooth muscle cells (VSMCs). METHODS: Tissue mass culture was done to get vascular smooth muscle cells of pulmonary artery in newborn pigs. Two methods were used to interfere VSMCs: adding adenoviral recombined body (Ad5CMV-PalphaRtr, ACP) with three different concentrations of truncated PDGF-alpha receptor into the cultures, or adding three concentrations of PDGF-BB after the treatment with mid-concentration of ACP. VSMC apoptosis, cellular cycle and expression of c-sis were observed using flow-cytometry, and the expression of c-sis mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: ACP with mid- to- high concentrations could restrain the proliferation of VSMCs apparently with the increase of G(0)/G(1) cells. The apoptotic rate presented an ascending tendency. The differences among the groups were of statistically significant. Affected by mid- concentration of ACP, PDGF-BB did not exhibit a significantly accelerating effect on the changes of cellular cycle and VSMC apoptosis. The expression of c-sis mRNA was up-regulated under the effect of ACP. Affected by mid-concentration of ACP and PDGF-BB, c-sis mRNA expressed was down-regulated. CONCLUSION: Mid- to- high concentration of ACP is a powerful inhibitor of cellular proliferation for pulmonary artery VSMCs. It can significantly increase cells in number in G(0)/G(1) phase, apoptosis and c-sis mRNA expression.

Fusion of COL1A1 exon 29 with PDGFB exon 2 in a der(22)t(17;22) in a pediatric giant cell fibroblastoma with a pigmented Bednar tumor component. Evidence for age-related chromosomal pattern in dermatofibrosarcoma protuberans and related tumors.

In contrast with classic dermatofibrosarcoma protuberans (DP), genetic information about the juvenile or pigmented variant forms of DP, so-called giant cell fibroblastoma (GCF) and Bednar tumor (BT), is limited. In the sole karyotyped case of BT a supernumerary ring containing chromosomes 17 and 22 sequences, similar to DP rings, was reported, whereas in three GCF cases, t(17;22) or der(22)t(17;22) with COL1A1-PDGFB fusion involving exons 11, 40, and 47, respectively, have been described. Here, we report the first cytogenetic and molecular analysis of a tumor from a 5-year-old child that contained both GCF and BT components. The karyotype and molecular analyses confirmed the common histogenetic origin between DP, GCF, and BT in showing the presence of a der(22)t(17;22) fusing the COL1A1 exon 29 to PDGFB exon 2. Because COL1A1 exon 29 has been involved previously in gene fusion with PDGFB exon 2 in several cases of adult or infantile DP presenting either t(17;22) or ring chromosomes, our results support the concept that DP, GCF, and BT are morphologic variants of a same entity, rather than distinct tumors. Of interest, our findings give prominence to the relation between patient age and the chromosomal rearrangement pattern in DP and related tumors. Whereas only a few adult DP cases presented with translocations, all the infantile cases, either DP, GCF, or mixed BT-GCF, as shown here, contained translocation derivatives but not ring chromosomes. All the ring chromosomes were observed in adult cases. With respect to cytogenetic studies, DP, GCF, and BT appear to be a unique model for age-related chromosomal rearrangement progression.

Effects of H-ras and v-sis overexpression on N-acetylglucosaminyltransferase V and metastasis-related phenotypes in human hepatocarcinoma cells.

Oncogenes and N-acetylglucosaminyltransferase (GnT-V) are both commonly associated with carcinogenesis and metastasis. In order to elucidate the relationship between oncogenes and GnT-V, two oncogenes, H-ras and v-sis/PDGF (platelet-derived growth factor), were selected, and the effects of their overexpression on GnT-V in 7721 human hepatocarcinoma cells were investigated. The results showed that the over expression of H-ras or v-sis/PDGF-B up-regulated the activities of GnT-V to various degrees in the transfected cells. In H-ras- and PDGF-B-overexpressing cells, the activity of GnT-V was up-regulated to double the normal value. The transient expression of v-sis, which produces a protein almost identical to PDGF-B, stimulated the GnT-V activity by 80.3%, and the effect was more pronounced (increased by 182.5%) in 7721 cells with stable expression of v-sis. The stimulating effect was entirely abolished by treatment with PDGF-B antibody. The staining of asparagine-linked glycans (N-glycans) in the H-ras- and v-sis-overexpressing 7721 cells was intensified when horseradish peroxidase-labeled leucoagglutinating phytohemogglutinin was used as a probe, indicating the increased content of beta1,6GlcNAc branching on the N-glycans. The enhancement of GnT-V mRNA expression was also observed in H-ras- and v-sis- overexpressing cells, indicating that H-ras and v-sis regulated GnT-V via the transcription of GnT-V mRNA and the synthesis of GnT-V protein. The cells overexpressing H-ras and v-sis displayed some changes in metastasis-related phenotypes, including acceleration of cell growth, decline of cell adhesion to fibronectin, and an increase of cell adhesion to laminin, as well as increased invasiveness through Matrigel. These results indicated that the alteration of cell adhesion and invasion induced by oncogenes is closely related to the up-regulation of GnT-V activity and its product, beta1,6GlcNAc branching in N-glycans on the cell surface.

Novel germline p16(INK4) allele (Asp145Cys) in a family with multiple pancreatic carcinomas. Mutations in brief no. 148. Online.

As part of a search for causative genes of familial pancreatic carcinoma, the p16 genes were sequenced in members of 21 families with a phenotype of familial pancreatic carcinoma (2 or more first degree relatives affected). One family was found in which members carried a novel p16 allele with a G to T transversion at position 451, creating a missense amino acid change at codon 145 (Asp to Cys) and possibly disrupting the donor splice site of the exon 2/3 boundary. This coding change is not a known polymorphism, and occurs at a codon position in which another missese/splicing change has been shown to be linked to familial melanoma/pancreas cancer.