1/124. Abdominal lymphatic dysplasia and 22q11 microdeletion.We report the case of a child with 22q11 microdeletion who presented with abdominal lymphatic dysplasia resulting in exsudative enteropathy. This primitive and localized lymphatic malformation is consistent with the vascular theory in the velocardiofacial syndrome.- - - - - - - - - - ranking = 1keywords = deletion, q (Clic here for more details about this article) |
2/124. Possible extrathymic development of nonfunctional T cells in a patient with complete digeorge syndrome.Complete digeorge syndrome is characterized by the clinical triad of cardiac malformation, hypocalcemia, and T cell immunodeficiency due to congenital athymia. We describe an infant with complete digeorge syndrome who at presentation had no circulating T cells detectable by flow cytometry. The patient spontaneously developed circulating T cells but these cells did not proliferate in response to mitogens. The T cell receptor Vbeta repertoire was severely restricted. All T cells were host, not maternal, as assessed by fluorescent in situ hybridization evaluation of 22q11 hemizygosity. At autopsy, this patient had no grossly detectable thymus tissue and no microscopic evidence for thymopoiesis. These findings suggest that appearance of T cells in infants with complete digeorge syndrome may represent oligoclonal expansions of a small number of T cells that may have matured extrathymically and which do not respond in vitro to mitogen stimulation.- - - - - - - - - - ranking = 0.0027606971618582keywords = q (Clic here for more details about this article) |
3/124. Partial digeorge syndrome in two patients with a 10p rearrangement.We describe 2 patients with a partial digeorge syndrome (facial dysmorphism, hypoparathyroidism, renal agenesis, mental retardation) and a rearrangement of chromosome 10p. The first patient carries a complex chromosomal rearrangement, with a reciprocal insertional translocation between the short arm of chromosome 10 and the long arm of chromosome 8, with karyotype 46, XY ins(8;10) (8pter 8q13::10p15-->10p14::8q24.1-->8qter) ins(10:8) (10pter--> 10p15::8q24.1-->8q13::10p14-->10qter). The karyotype of the second patient shows a terminal deletion of the short arm of chromosome 10. In both patients, the breakpoints on chromosome 10p reside outside the previously determined DiGeorge critical region II (DGCRII). This is in agreement with previous reports of patients with a terminal deletion of 10p with breakpoints distal to the DGCRII and renal malformations/hypoparathyroidism, and thus adds to evidence that these features may be caused by haploinsufficiency of one or more genes distal to the DGCRII.- - - - - - - - - - ranking = 0.41104278864743keywords = deletion, q (Clic here for more details about this article) |
4/124. Patient with a 22q11.2 deletion with no overlap of the minimal digeorge syndrome critical region (MDGCR).The apparent lack of genotype/phenotype correlation in patients with the DiGeorge anomaly and velocardiofacial syndrome (DGA/VCFS; the "22q11 deletion syndrome") indicates a complex genetic condition. Most cases, whatever the phenotype, have a 1.5-3 Mb chromosomal deletion that includes the minimal DiGeorge critical region (MDGCR). Another potential critical region on 22q11 has been suggested based on two patients with distal deletions outside the MDGCR. We report on a patient with a VCFS phenotype who has a deletion, mapped by short tandem repeat polymorphic loci and fluorescence in situ hybridization analysis, distal to and not overlapping the MDGCR. This patient is deleted for several genes, including the T-box 1 gene (TBX1; a transcription regulator expressed early in embryogenesis) and catechol-O-methyltransferase (COMT; involved in neurotransmitter metabolism). We discuss the role these two genes may play in the clinical phenotype of the patient.- - - - - - - - - - ranking = 11.186484053392keywords = deletion syndrome, deletion, q (Clic here for more details about this article) |
5/124. Interruption of the aortic arch at the isthmus with digeorge syndrome and 22q11.2 deletion.A 6-day-old male with interruption of the aortic arch at the isthmus (type A) had the typical phenotype of digeorge syndrome. There was also a doubly committed juxta-arterial ventricular septal defect and an unobstructed left ventricular outflow tract. Hypoplasia of the thymus was confirmed during a modified Blalock-Park operation. He had persistent hypocalcemia, and was susceptible to infection. He was subsequently revealed by the use of fluorescence in situ hybridization analysis to have 22q11.2 deletion. Interruption of the aortic arch at the isthmus is presumed to reflect abnormal fetal hemodynamics, and is considered a distinct pathogenetic entity from interruption between the left common carotid and subclavian arteries, the latter being the variant more frequently associated with digeorge syndrome. In our case, the 22q11.2 deletion likely played a major role in the etiology of the interrupted aortic arch.- - - - - - - - - - ranking = 1.2055213943237keywords = deletion, q (Clic here for more details about this article) |
6/124. CATCH 22 syndrome: report of 7 infants with follow-up data and review of the recent advancements in the genetic knowledge of the locus 22q11.CATCH 22 is a medical acronym for Cardiac defects, Abnormal facies, Thymic hypoplasia, cleft palate, and hypocalcemia, and a variable deletion on chromosome 22. The deletion within the chromosome region of 22q11 may occur in patients with three well-described dysmorphologic cardiological syndromes: digeorge syndrome (DGS), velocardiofacial syndrome (VCFS), and conotruncal anomaly face syndrome (CTAFS). We report in detail seven infants with a deletion of the locus 22q11 showing overlapping clinical features of DGS and CTAFS with complex congenital heart defects (double outlet right ventricle, atresia or stenosis of the pulmonary valve, atrial and ventricular septal defects, patent ductus arteriosus, tetralogy of fallot, major aortopulmonary collateral arteries, arcus aortae dexter, and persistence of the left superior vena cava). A homograft was implanted between the right ventricle and the main stem of the pulmonary artery in 2 patients, while a balloon valvuloplastic of the pulmonary valve was performed in one patient only. Pulmonary hemorrhage, acute hypoxia, and aspergillus pneumonia were the complications. death occurred in three out of seven patients. Recent advancements in the genetic knowledge of the locus 22q11 are described. Since the locus 22q11 is highly heterogeneous, the CATCH 22 acronym should be used and temporarily the old eponyms should be abandoned waiting for the identification of the different genes.- - - - - - - - - - ranking = 0.61380348580929keywords = deletion, q (Clic here for more details about this article) |
7/124. Atypical deletions suggest five 22q11.2 critical regions related to the DiGeorge/velo-cardio-facial syndrome.Deletions of chromosome 22q11.2 have been associated with distinct phenotypes including digeorge syndrome (DGS) and velo-cardio-facial (VCFS) syndrome. These diseases result from a failure to form derivatives of the third and fourth branchial arches during development. DGS/VCFS deletions usually encompass about 3 Mb of genomic dna in more than 90% of patients. However, deletion mapping studies have failed to demonstrate the existence of a single small region of overlap (SRO) and ruled out any obvious correlation between site or size of deletion and severity of clinical phenotype. We describe three patients carrying 'atypical' deletions presenting the DGS/VCFS phenotype. A comparative analysis of deletions in our patients and those previously published has suggested the existence of five distinct critical regions within the 22q11.2 locus. This observation argues that DGS/VCFS results from haploinsufficiency secondary to a complex and as yet unexplained molecular mechanism, probably involving chromatin effects in mediating gene expression throughout the entire region.- - - - - - - - - - ranking = 1.7917179085144keywords = deletion, q (Clic here for more details about this article) |
8/124. An HDR (hypoparathyroidism, deafness, renal dysplasia) syndrome locus maps distal to the digeorge syndrome region on 10p13/14.Partial monosomy 10p is a rare chromosomal condition and a significant proportion of patients show features of digeorge syndrome (DGS) and velocardiofacial syndrome (VCFS). A critical haploinsufficiency region for DGS/VCFS was defined on 10p (DGCR2). We performed molecular deletion analysis of two further patients with partial monosomy 10p, who showed hypoparathyroidism, deafness, and renal dysplasia or renal insufficiency, but no cardiac defect, cleft palate, or reduced T cell levels. Previously, the combination of hypoparathyroidism, deafness, and renal dysplasia has been proposed to represent a specific syndrome (MIM 146255) under the acronym HDR. In addition to the two patients in this report, at least four published cases with partial monosomy 10p show the triad of HDR and 14 other patients present with at least two of the three features. We therefore conclude that HDR syndrome can be associated with partial monosomy 10p. Based on molecular deletion analysis and the clinical data, we suggest that the DGS/VCFS phenotype associated with 10p deletion can be considered as a contiguous gene syndrome owing to haploinsufficiency of two different regions. Hemizygosity of the proximal region, designated DGCR2, can cause cardiac defect and T cell deficiency. Hemizygosity of the distal region, designated HDR1, can cause hypoparathyroidism and in addition sensorineuronal deafness and renal dysplasia/insufficiency or a subset of this triad.- - - - - - - - - - ranking = 0.59171790851443keywords = deletion (Clic here for more details about this article) |
9/124. Stenting of stenosed aortopulmonary collaterals and shunts for palliation of pulmonary atresia/ventricular septal defect.patients with unrepaired pulmonary artery atresia and ventricular septal defect (PA/VSD) depend on aortoplumonary collaterals and surgically created shunts for pulmonary blood flow. These vessels frequently develop stenoses with time, leading to hypoperfusion of lung segments and systemic hypoxemia. The purpose of this article is to describe catheter palliation of hypoxemic patients with PA/VSD who were not candidates for surgical repair. We present our experience with stent implantation for stenosis of aortopulmonary collaterals and shunts in these patients. Three patients with hypoplastic pulmonary arteries underwent stent placement in aortopulmonary collateral arteries (APCAs) or their shunts. Technical aspects of the interventional catheterization procedure are discussed in detail. Case 1 underwent placement of five stents in collateral vessels and one stent in the Blalock-Taussig shunt (BT) with dramatic increase in vessel size and improvement in saturations from 70% to 89%. Case 2 underwent placement of two overlapping stents in a collateral vessel with an increase in diameter of the collateral vessel from 2.3 to 6 mm and an improvement in saturation from 68% to 88%. Case 3 underwent placement of three overlapping stents in a BT shunt with an increase in diameter of the shunt from 2.2 to 6.6 mm and an improvement in saturation from 71% to 89%. All three patients had excellent clinical improvement and stable saturation at follow-up. Stent placement for maintaining patency of APCAs and aortopulmonary shunts is feasible and safe.- - - - - - - - - - ranking = 0.0027606971618582keywords = q (Clic here for more details about this article) |
10/124. Dual-probe fluorescence in situ hybridization assay for detecting deletions associated with VCFS/digeorge syndrome I and digeorge syndrome II loci.Over 90% of patients with digeorge syndrome (DGS) or velocardiofacial syndrome (VCFS) have a microdeletion at 22q11.2. Given that these deletions are difficult to visualize at the light microscopic level, fluorescence in situ hybridization (FISH) has been instrumental in the diagnosis of this disorder. Deletions on the short arm of chromosome 10 are also associated with a DGS-like phenotype. Since deletions at 22q11.2 and at 10p13p14 result in similar findings, we have developed a dual-probe FISH assay for screening samples referred for DGS or VCFS in the clinical laboratory. This assay includes two test probes for the loci, DGSI at 22q11.2 and DGSII at 10p13p14, and centromeric probes for chromosomes 10 and 22. Of 412 patients tested, 54 were found to be deleted for the DGSI locus on chromosome 22 (13%), and a single patient was found deleted for the DGSII locus on chromosome 10 (0. 24%). The patient with the 10p deletion had facial features consistent with VCFS, plus sensorineural hearing loss, and renal anomalies. cytogenetic analysis showed a large deletion of 10p [46, XX,del(10)(p12.2p14)] and FISH using a 10p telomere region-specific probe confirmed the interstitial nature of the deletion. Analysis for the DGSI and the DGSII loci suggests that the deletion of the DGSII locus on chromosome 10 may be 50 times less frequent than the deletion of DGSI on chromosome 22. The incidence of deletions at 22q11.2 has been estimated to be 1 in 4000 newborns; therefore, the deletion at 10p13p14 may be estimated to occur in 1 in 200,000 live births.- - - - - - - - - - ranking = 2.7751537255433keywords = deletion, q (Clic here for more details about this article) |
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