The tumor suppressor gene TRC8/RNF139 is disrupted by a constitutional balanced translocation t(8;22)(q24.13;q11.21) in a young girl with dysgerminoma

Background

RNF139/TRC8 is a potential tumor suppressor gene with similarity to PTCH, a tumor suppressor implicated in basal cell carcinomas and glioblastomas. TRC8 has the potential to act in a novel regulatory relationship linking the cholesterol/lipid biosynthetic pathway with cellular growth control and has been identified in families with hereditary renal (RCC) and thyroid cancers. Haploinsufficiency of TRC8 may facilitate development of clear cell-RCC in association with VHL mutations, and may increase risk for other tumor types. We report a paternally inherited balanced translocation t(8;22) in a proposita with dysgerminoma.

Methods

The translocation was characterized by FISH and the breakpoints cloned, sequenced, and compared. DNA isolated from normal and tumor cells was checked for abnormalities by array-CGH. Expression of genes TRC8 and TSN was tested both on dysgerminoma and in the proposita and her father.

Results

The breakpoints of the translocation are located within the LCR-B low copy repeat on chromosome 22q11.21, containing the palindromic AT-rich repeat (PATRR) involved in recurrent and non-recurrent translocations, and in an AT-rich sequence inside intron 1 of the TRC8 tumor-suppressor gene at 8q24.13. TRC8 was strongly underexpressed in the dysgerminoma. Translin is underexpressed in the dysgerminoma compared to normal ovary.

TRC8 is a target of Translin (TSN), a posttranscriptional regulator of genes transcribed by the transcription factor CREM-tau in postmeiotic male germ cells.

Conclusion

A role for TRC8 in dysgerminoma may relate to its interaction with Translin. We propose a model in which one copy of TRC8 is disrupted by a palindrome-mediated translocation followed by complete loss of expression through suppression, possibly mediated by miRNA.

Hemodynamically supported percutaneous coronary revascularization improves left ventricular function in patients with ischemic dilated cardiomyopathy at very high risk for surgery: a single-center experience

BACKGROUND

Coronary artery bypass grafting is often considered for patients with ischemic cardiomyopathy, but age, comorbidities and depressed left ventricular function can increase surgical risk. Percutaneous left ventricular assist devices (pLVAD) may facilitate complex percutaneous coronary interventions (PCI) in the setting of severely impaired left ventricular function, thus providing a possible alternative to thoracotomy in high-risk patients. The long-term effects of hemodynamically-supported PCI on left ventricular function and clinical outcome in these patients are poorly understood.

OBJECTIVE

To determine the effect of hemodynamically-supported multivessel PCI on left ventricular ejection fraction (LVEF) in patients with severe ischemic cardiomyopathy at very high operative risk.

METHODS

Retrospective case-series analysis of patients with ischemic cardiomyopathy at very high surgical risk who underwent prophylactic pLVAD implantation for hemodynamic support during complex PCI between January 2004 and February 2007. The main outcome variable was change in LVEF assessed by echocardiography 90 days or more after PCI. Major in-hospital adverse cardiovascular events (MACE), vascular complications and all-cause mortality were secondary endpoints.

RESULTS

Eleven patients with prior myocardial infarction and ischemic cardiomyopathy (mean age 73 +/- 14 years) underwent TandemHeart-supported PCI. The indications for prophylactic support were depressed LVEF and a large myocardial mass at risk. Baseline LVEF was 25 +/- 8%, increasing to 41 +/- 9% at a mean follow-up time of 15 +/- 15 months (p = 0.0004). There were no in-hospital MACE and only 1 vascular complication requiring blood transfusion.

CONCLUSIONS

PLVAD-supported PCI in patients with ischemic cardiomyopathy at very high risk for surgery is feasible and relatively safe. In combination with medical therapy, it results in significant improvement in LVEF by echocardiography.

Complex pathogenesis of Hirschsprung's disease in a patient with hydrocephalus, vesico-ureteral reflux and a balanced translocation t(3;17)(p12;q11)

Hirschsprung's disease (HSCR), a congenital complex disorder of intestinal innervation, is often associated with other inherited syndromes. Identifying genes involved in syndromic HSCR cases will not only help understanding the specific underlying diseases, but it will also give an insight into the development of the most frequent isolated HSCR. The association between hydrocephalus and HSCR is not surprising as a large number of patients have been reported to show the same clinical association, most of them showing mutations in the L1CAM gene, encoding a neural adhesion molecule often involved in isolated X-linked hydrocephalus. L1 defects are believed to be necessary but not sufficient for the occurrence of the intestinal phenotype in syndromic cases. In this paper, we have carried out the molecular characterization of a patient affected with Hirschsprung's disease and X-linked hydrocephalus, with a de novo reciprocal balanced translocation t(3;17)(p12;q21). In particular, we have taken advantage of this chromosomal defect to gain access to the predisposing background possibly leading to Hirschsprung's disease. Detailed analysis of the RET and L1CAM genes, and molecular characterization of MYO18A and TIAF1, the genes involved in the balanced translocation, allowed us to identify, besides the L1 mutation c.2265delC, different additional factors related to RET-dependent and -independent pathways which may have contributed to the genesis of enteric phenotype in the present patient.

Recurrent rearrangements of chromosome 1q21.1 and variable pediatric phenotypes

BACKGROUND

Duplications and deletions in the human genome can cause disease or predispose persons to disease. Advances in technologies to detect these changes allow for the routine identification of submicroscopic imbalances in large numbers of patients.

METHODS

We tested for the presence of microdeletions and microduplications at a specific region of chromosome 1q21.1 in two groups of patients with unexplained mental retardation, autism, or congenital anomalies and in unaffected persons.

RESULTS

We identified 25 persons with a recurrent 1.35-Mb deletion within 1q21.1 from screening 5218 patients. The microdeletions had arisen de novo in eight patients, were inherited from a mildly affected parent in three patients, were inherited from an apparently unaffected parent in six patients, and were of unknown inheritance in eight patients. The deletion was absent in a series of 4737 control persons (P=1.1x10(-7)). We found considerable variability in the level of phenotypic expression of the microdeletion; phenotypes included mild-to-moderate mental retardation, microcephaly, cardiac abnormalities, and cataracts. The reciprocal duplication was enriched in nine children with mental retardation or autism spectrum disorder and other variable features (P=0.02). We identified three deletions and three duplications of the 1q21.1 region in an independent sample of 788 patients with mental retardation and congenital anomalies.

CONCLUSIONS

We have identified recurrent molecular lesions that elude syndromic classification and whose disease manifestations must be considered in a broader context of development as opposed to being assigned to a specific disease. Clinical diagnosis in patients with these lesions may be most readily achieved on the basis of genotype rather than phenotype.

How I do it: endovascular stent deployment using a novel technique that obviates the need for introducer-sheath upsizing

A case is presented and a novel technique is described by which an endovascular stent is deployed in the venous outflow system of an arteriovenous fistula without the traditional exchange to a larger diameter introducer sheath.

Long-term survival using intra-aortic balloon pump and percutaneous right ventricular assist device for biventricular mechanical support of cardiogenic shock

Right ventricular (RV) involvement in acute inferior left ventricular (LV) myocardial infarction increases the risks of cardiogenic shock and in-hospital mortality. Acutely impaired RV performance results in reduced LV preload and, in combination with impaired LV contractility, causes severely reduced LV stroke volume and cardiac output. Here we report long-term patient survival after acute biventricular myocardial infarction (MI) using simultaneous RV support with a TandemHeart percutaneous ventricular assist device (Cardiac Assist Technologies, Pittsburgh, Pennsylvania) and LV support with an intra-aortic balloon pump. Further evaluation of completely percutaneous biventricular support in acute MI is warranted.

Percutaneous closure of a large PDA in a 35-year-old man with elevated pulmonary vascular resistance

The presence of a large patent ductus arteriosus (PDA) may result in significant pulmonary hypertension, which may not be reversible. We present the case of a 35-year-old man with pulmonary hypertension who had successful percutaneous closure of a large PDA with an Amplatzer muscular ventricular septal defect occluder and resolution of his pulmonary hypertension. The use of prior balloon test occlusion of the PDA suggested that the procedure would be successful, despite the lack of an immediate fall in the pulmonary artery pressure.

A recurrent 15q13.3 microdeletion syndrome associated with mental retardation and seizures

We report a recurrent microdeletion syndrome causing mental retardation, epilepsy and variable facial and digital dysmorphisms. We describe nine affected individuals, including six probands: two with de novo deletions, two who inherited the deletion from an affected parent and two with unknown inheritance. The proximal breakpoint of the largest deletion is contiguous with breakpoint 3 (BP3) of the Prader-Willi and Angelman syndrome region, extending 3.95 Mb distally to BP5. A smaller 1.5-Mb deletion has a proximal breakpoint within the larger deletion (BP4) and shares the same distal BP5. This recurrent 1.5-Mb deletion contains six genes, including a candidate gene for epilepsy (CHRNA7) that is probably responsible for the observed seizure phenotype. The BP4-BP5 region undergoes frequent inversion, suggesting a possible link between this inversion polymorphism and recurrent deletion. The frequency of these microdeletions in mental retardation cases is approximately 0.3% (6/2,082 tested), a prevalence comparable to that of Williams, Angelman and Prader-Willi syndromes.

How I do it: directional atherectomy for in-stent restenosis of a PTFE arteriovenous graft

We describe the use of directional atherectomy (DA) to restore patency of a thrombosed polytetrafluoroethylene arteriovenous graft with an in-stent restenosis at the venous anastomosis. Technically, the procedure described is not an atherectomy per se, but rather the removal of fibrosis and intimal hyperplasia with sharp endoluminal dissection. Certainly, the operator must be cautious when performing DA directly adjacent to a previously deployed stent. Nevertheless, our report suggests that there may be a role for DA in the treatment of severe, resistant in-stent stenosis. Further investigation is necessary to evaluate the safety and efficacy of the described technique.

Clinical spectrum of immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome)

BACKGROUND

Immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome) is a rare autosomal recessive disease characterised by facial dysmorphism, immunoglobulin deficiency and branching of chromosomes 1, 9 and 16 after PHA stimulation of lymphocytes. Hypomethylation of DNA of a small fraction of the genome is an unusual feature of ICF patients which is explained by mutations in the DNA methyltransferase gene DNMT3B in some, but not all, ICF patients.

OBJECTIVE

To obtain a comprehensive description of the clinical features of this syndrome as well as genotype-phenotype correlations in ICF patients.

METHODS

Data on ICF patients were obtained by literature search and additional information by means of questionnaires to corresponding authors.

RESULTS AND CONCLUSIONS

45 patients all with proven centromeric instability were included in this study. Facial dysmorphism was found to be a common characteristic (n = 41/42), especially epicanthic folds, hypertelorism, flat nasal bridge and low set ears. Hypo- or agammaglobulinaemia was demonstrated in nearly all patients (n = 39/44). Opportunistic infections were seen in several patients, pointing to a T cell dysfunction. Haematological malignancy was documented in two patients. Life expectancy of ICF patients is poor, especially those with severe infections in infancy or chronic gastrointestinal problems and failure to thrive. Early diagnosis of ICF is important since early introduction of immunoglobulin supplementation can improve the course of the disease. Allogeneic stem cell transplantation should be considered as a therapeutic option in patients with severe infections or failure to thrive. Only 19 of 34 patients showed mutations in DNMT3B, suggesting genetic heterogeneity. No genotype-phenotype correlation was found between patients with and without DNMT3B mutations.

Does detection of carotid plaque affect physician behavior or motivate patients?

BACKGROUND

Imaging techniques to identify subclinical atherosclerosis are becoming more widespread, but few data exist regarding their influence on patient or physician behavior. We evaluated the impact of ultrasound screening to identify carotid artery plaques on physician treatment plans and patient motivation.

METHODS

Subjects included asymptomatic patients without known vascular disease who had 2 or more cardiac risk factors. Circumferential scanning of the right and left carotid arteries to identify carotid plaques was performed using a handheld ultrasound device in an office setting. The physician's initial treatment recommendations were assessed before and after the results of the carotid scan were reported. Subjects completed a survey to assess motivation to make lifestyle changes before and after the results of the scan were provided.

RESULTS

Fifty subjects were enrolled over 9 months. Their mean (SD) age was 54.0 (10.4) years and their mean Framingham 10-year cardiovascular risk was 7.8% (7.9%). More than half (58%) of the subjects had at least one carotid plaque. When carotid plaque was identified, physicians were more likely to prescribe aspirin (P = .031) and lipid-lowering therapy (P = .004). Although subjects with carotid plaque reported an increase in their perceived likelihood of developing heart disease (P = .013), they did not report increased motivation to make lifestyle changes.

CONCLUSIONS

Ultrasound screening for carotid plaque in an office setting can alter physician treatment plans. Although the presence of plaque increased patient perception of cardiovascular risk, it did not motivate patients to make lifestyle changes.

Delayed complete heart block secondary to jailed first septal perforator

Partial or total occlusion of septal perforator branches can occur during stenting of the proximal and mid portion of the left anterior descending artery, secondary to plaque snow plowing and/or stent "jailing". Flow compromise in a sizeable septal branch can result in a myocardial infarction or in atrioventricular conduction abnormalities. Complete heart block has been described at the time of the procedure, and though it is usually transient, it may require temporary pacing. We report a case of delayed, symptomatic and permanent complete atrio-ventricular block that occurred 2 days after the index procedure, requiring implantation of a permanent pacemaker.

Overexpression of the C-type natriuretic peptide (CNP) is associated with overgrowth and bone anomalies in an individual with balanced t(2;7) translocation

Longitudinal bone growth is determined by the process of endochondral ossification in the cartilaginous growth plate, which is located at both ends of vertebrae and long bones and involves many systemic hormones and local regulators. We report the molecular characterization of a de novo balanced t(2;7)(q37.1;q21.3) translocation in a young female with Marfanoid habitus and skeletal anomalies. The translocation was characterized by fluorescence in situ hybridization (FISH), checked for other abnormalities by array-comparative genomic hybridization (CGH), and finally, the breakpoints were cloned, sequenced, and compared. Biochemical dosage was applied to study the possible mechanisms that may cause the proposita's phenotype. The breakpoint on chromosome 2 disrupts the hypothetical gene MGC42174 (HUGO-approved symbol DIS3L2) and is located in the proximity of the NPPC gene coding for C-type natriuretic peptide (CNP), a molecule that regulates endochondral bone growth. CNP plasma concentration was doubled in the proband compared to five normal controls, while NPPC was substantially overexpressed in her fibroblasts. A transgenic mouse generated to target NPPC overexpression in bone showed a phenotype highly reminiscent of the patient's phenotype. The breakpoint on chromosome 7 is localized proximally at about 75 kb from the COL1A2 gene. The COL1A2 allele on the derivative chromosome was strongly underexpressed in fibroblasts, but total collagen was not significantly different from controls. Several evidences support the conclusion that the proband's abnormal phenotype is associated with C-type natriuretic peptide overexpression.

Two classes of low-copy repeats comediate a new recurrent rearrangement consisting of duplication at 8p23.1 and triplication at 8p23.2

We describe a new type of rearrangement consisting of the duplication of 8p23.1 and the triplication of 8p23.2 [dup trp(8p)] in two patients affected by mental retardation and minor facial dysmorphisms. Array-comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH), and genotyping of polymorphic loci allowed us to demonstrate that this rearrangement is mediated by the combined effects of two unrelated low-copy repeats (LCRs). The first set of LCRs consists of the two clusters of olfactory receptor genes (OR-REPs) lying at 8p23.1. The second type of LCRs consists of a 15-kb segmental duplication, lying in inverted orientation at 8p23.2 and enclosing a nonrepeated sequence of approximately 130 kb, named MYOM2-REP because of its proximity to the MYOM2 gene. The molecular characterization of a third case with a dicentric chromosome 8 demonstrated that the rearrangement had been generated by nonallelic homologous recombination between the two MYOM2-REPs. Based on our findings, we propose a model showing that a second recombination event at the level of the OR-REPs leads to the formation of the dup trp(8p) chromosome. This rearrangement can only arise during meiosis in heterozygous carriers of the polymorphic 8p23.1 inversion, whereas in subjects with noninverted chromosomes 8 or homozygous for the inversion only the dicentric chromosome can be formed. Our study demonstrates that nonallelic homologous recombination involving multiple LCRs can generate more complex rearrangements and cause a greater variety of genomic diseases.

A large analphoid invdup(3)(q22.3qter) marker chromosome characterized by array-CGH in a child with malformations, mental retardation, ambiguous genitalia and Blaschko's lines

We report a new case of mosaic chromosome 3-derived marker chromosome, present in fibroblasts but not in lymphocytes, found in a child with malformations, mental retardation and ambiguous genitalia. Cytogenetic and molecular analysis showed that the supernumerary invdup(3)(q22.3qter) chromosome was negative at FISH with alpha satellite probe. The presence of a functional neocentromere was confirmed by immunofluorescence with antibodies to centromere proteins (CENPs). Definition of the marker breakpoints has been done through array-CGH. The skin of the patient presented dyschromic areas ordered along Blaschko's lines. The invdup(3q) marker chromosome was present only in fibroblasts from the dark skin biopsy, while lymphocytes and fibroblasts from the normal skin showed a normal male karyotype. Expression of the HPS3 gene (MIM: 606118) was more than two times higher in dark skin fibroblasts. Neocentromeres are most often observed on chromosomal arm fragments that have separated from an endogenous centromere, and therefore actually confer mitotic stability to what would have been acentric fragments. To our knowledge, this invdup(3q) analphoid marker is the largest among the several reported so far. Parental origin and possible mode of formation have been defined by DNA polymorphisms studies. The size of the duplicated marker chromosome and its frequency and tissue distribution may be relevant to the severity of the propositus' phenotype.

Characterization of a recurrent 15q24 microdeletion syndrome

We describe multiple individuals with mental retardation and overlapping de novo submicroscopic deletions of 15q24 (1.7-3.9 Mb in size). High-resolution analysis showed that in three patients both proximal and distal breakpoints co-localized to highly identical segmental duplications (>51 kb in length, > 94% identity), suggesting non-allelic homologous recombination as the likely mechanism of origin. Sequencing studies in a fourth individual provided base pair resolution and showed that both breakpoints in this case were located in unique sequence. Despite the differences in the size and location of the deletions, all four individuals share several major features (growth retardation, microcephaly, digital abnormalities, hypospadias and loose connective tissue) and resemble one another facially (high anterior hair line, broad medial eyebrows, hypertelorism, downslanted palpebral fissures, broad nasal base, long smooth philtrum and full lower lip), indicating that this represents a novel syndrome caused by haploinsufficiency of one or more dosage-sensitive genes in the minimal deletion region. Our results define microdeletion of 15q24 as a novel recurrent genomic disorder.

The breakpoint identified in a balanced de novo translocation t(7;9)(p14.1;q31.3) disrupts the A-kinase (PRKA) anchor protein 2 gene (AKAP2) on chromosome 9 in a patient with Kallmann syndrome and bone anomalies

We report the molecular characterization of a patient with Kallmann syndrome and bone anomalies bearing a balanced de novo translocation t(7;9)(p14.1;q31.3) which completely disrupts the A-kinase anchor protein 2 gene (AKAP2) on chromosome 9. In order to investigate the role of AKAP2 in the pathogenesis of the disease, we analyzed the expression of Akap2 in mouse embryos. The expression pattern was consistent with the phenotype observed and mAkap2 was actually found in the olfactory bulb and in the cartilagineous structures of the embryo. Since AKAP2 is supposed to bind and compartmentalize the PKA, we also analyzed the distribution and quantity of PKA in limphoblastoid cell lines of the patient compared with a control; these experiments did not demonstrate any differences between the cell lines. Furthermore a collection of 98 DNA samples from sporadic Kallmann patients was screened for mutations in this gene. The analysis revealed two different sequence variations observed in two patients but not in 200 control chromosomes: since they have been detected also in the unaffected mother of one of the two patients we can assume that they are rare polymorphisms, although we cannot exclude that they represent mutations with incomplete penetrance. Our findings suggest that the complex phenotype with Kallmann syndrome and bone anomalies observed in our patient could be the result of the interruption of the AKAP2 gene. However, a position effect mediated by the translocation could not be excluded. The screening of AKAP2 in other Kallmann patients will be necessary to elucidate its role in the pathogenesis of the disease.

Vertebral artery embolic protection via ipsilateral brachial approach during left subclavian artery angioplasty and stenting--a case report

The purpose of this report is to explore angioplasty and stenting with cerebral embolic protection as a salvage procedure for a compromised carotid-subclavian bypass in the presence of antegrade vertebral artery flow. A 76-year-old woman with a carotid-subclavian bypass presented with graft infection. Failure of medical therapy to treat the infection prompted surgical removal of the graft. The native subclavian artery was still patent, but a severe complex proximal stenosis was present with antegrade flow into the left vertebral artery. Angioplasty and stenting of the subclavian artery was performed with cerebral protection achieved by positioning a FilterWire EX in the left vertebral artery via the left brachial artery approach. Deployment of a filter device in the vertebral artery via the brachial or radial approach can provide embolic protection without interfering with the subclavian artery stenting. The successful treatment of the subclavian artery enabled the complete removal of the infected graft without need for major vascular reconstruction.

Identification and molecular modelling of a novel familial mutation in the SRY gene implicated in the pure gonadal dysgenesis

SRY gene is responsible for initiating male sexual differentiation. The protein encoded by SRY contains a homeobox (HMG) domain, which is a DNA-binding domain. Mutations of the SRY gene are reported to be associated with XY pure gonadal dysgenesis. The majority of these are de novo mutations affecting only one individual in a family. Only a small subset of mutations is shared between the father and one or more of his children. Most of these familial mutations are localized within the HMG box and only two are at the N-terminal domain of the SRY protein. Herein, we describe a young girl with pure gonadal dysgenesis and her father carrying a novel familial mutation in the SRY gene at codon number 3. This mutation is resulting in a serine (S) to leucine (L) substitution. The secondary structure of the SRY protein was carried out by protein modelling studies. This analysis suggests, with high possibility, that the N-terminal domain of the SRY protein, where we found the mutation, could form an alpha-helix from amino acid in position 2 to amino acid in position 13. The secondary structure prediction and the chemical properties of serine to leucine substitution stands for a potential disruption of this N-terminal alpha-helix in the SRY protein. This mutation could have some role in impeding the normal function of the SRY protein.

Molecular characterization of a t(2;6) balanced translocation that is associated with a complex phenotype and leads to truncation of the TCBA1 gene

The molecular characterization of balanced chromosomal rearrangements has often been a powerful tool for the positional identification of genes associated with specific diseases. In some instances, these rearrangements may be associated with a variety of different phenotypes, and thus establishing a genotype-phenotype correlation may be a complex process. However, molecular characterization of the rearrangement remains a useful tool for diagnoses or prognoses, or for identifying new genes and establishing a gene-to-function relationship. In this work we describe the characterization of a de novo balanced translocation t(2;6)(q24.3;q22.31) found in a patient with a complex phenotype. The major clinical finding was a severe neurological involvement. Thanks to the molecular characterization of this translocation we found that the rearrangement led to the truncation of the TCBA1 gene on chromosome 6q. We found that the gene is transcribed in different splice variants and is highly specific for the central nervous system. TCBA1 does not show any similarity with other known genes, and no information is available about its function. However, the gene appears to be well conserved among species, and we were able to infer the sequence of a putative mouse homolog of TCBA1. This allowed us to perform a more detailed expression study in mice, thus confirming its specificity for the nervous system. This finding is of particular interest because it suggests that TCBA1 may be correlated with the neurological phenotype of our patient, and possibly mutated in genetic diseases with a neurological phenotype.

Treatment of an Angio-Seal™-related vascular complication using the SilverHawk™ plaque excision system: A case report

The Angio-Seal is a user-friendly and safe arterial closure device increasingly used after percutaneous diagnostic and interventional procedures. Although it achieves rapid hemostasis and facilitates early patient mobilization, its use can be associated with vascular complications. A specific problem related to the device is protrusion of the collagen plug into the artery, causing either acute occlusion or symptomatic stenosis. When this occurs, treatment with balloon angioplasty alone is usually suboptimal, while stenting of the common femoral artery may be undesirable. In this report we describe a novel application of the SiverHawk plaque excision system to treat a highly eccentric stenosis at the site of a previously deployed Angio-Seal. Since the device allows preferential cutting in the direction of the lesion and collagen plug debulking, it may be ideally suited to treat this complication without the need for stenting of the common femoral artery.