Chromosome 22 microdeletion by F.I.S.H. in isolated congenital heart disease

Objective To analyze the frequency of del22q11.2 in non-syndromic CHDs using classical cytogenetics and Fluorescence In Situ Hybridization (FISH) technique in Indian population. Methods 105 prospective cases which included 6 families with isolated, non-syndromic cardiac defects were analyzed clinically by a cardiologist and a geneticist. The cases were then subjected to karyotypic (classical cytogenetics) as well as FISH analysis. The efficacy of FISH technique was compared with inference drawn from classical cytogenetics. Results Karyotypic analysis of all the 105 patients revealed a normal chromosomal complement. Microdeletion 22q11.2 was observed in six patients (5.71%) by FISH studies. FISH studies were also performed on the parents of these six patients who revealed a normal chromosome 22. No correlation was found between clinical features (mild or unspecific) with 22q11.2 microdeletion. Conclusion The testing for microdeletion 22q11.2 in isolated non-syndromic patients using FISH technique is mandatory even when mild/unspecific extracardiac abnormalities are seen in the patients.     

FISH investigation of 22q11.2 deletion in patients with immunodeficiency and/or cardiac abnormalities

DiGeorge anomaly/velocardiofacial syndrome (DG/VCFS), called 22q11.2 deletion syndrome in general, is the most common chromosomal deletion syndrome found in humans. Typical facial features, palatal defects, conotruncal abnormalities of the heart, aplasia/hypoplasia of the parathyroid glands and of thymus are characteristics of this syndrome. Deletions of chromosome 22q11.2 (del22q11.2) are the leading causes of DG7VCFS. We report on a systematic search by fluorescence in situ hybridization (FISH) for deletions of chromosomes 22q11.2 in patients with a clinical suspicion or diagnosis of DG/VCFS. Using FISH we studied a series of 43 patients with suspected DG/VCFS. In this study, a total of 43 patients were investigated for the presence of a 22q11.2 deletion over a two-year period. Del22q11.2 was detected in 5 of the 43 patients tested. All patients with deletion had hypocalcemia, 80% had cardiac defects, 40% had facial dysmorphism, 40% had immunodeficiency , and 20% had otolaryngeal abnormalities. Chromosome 22q11.2 deletion is a relatively common condition and is readily diagnosed by FISH. We suggest that FISH analysis of 22q11.2 deletion should be performed in the presence of combined of hypocalcemia and congenital cardiac malformations, with or without any characteristics of the disease. This may facilitate an early diagnosis in such patients.     

单纯性圆锥动脉干畸形22q11.2微缺失发生率及临床表型研究

目的 探讨单纯性圆锥动脉干畸形(CTD)染色体22q11.2微缺失发生率及临床表型分析.方法 应用多重连接探针扩增法(MLPA)对77例0～10岁单纯性CTD患儿进行染色体22q11.2微缺失筛查,并对阳性样本进行荧光原位杂交(FISH)验证.采用Fisher精度检验,P＜0.05有统计学意义.结果 用MLPA对77例单纯性CTD患儿进行了22号染色体微缺失筛查,其中55例法乐四联症(TOF),4例肺动脉闭锁伴室间隔缺损(PA-VSD),8例右室双出口(DORV),10例大动脉转位(TGA).6例(7.8%)患儿存在染色体22q 11.2微缺失,其中4例为TOF,1例为PA-VSD,1例为DORV;10例TGA患儿中均未发现22q11.2缺失.结论 单纯性CTD染色体22q 11.2微缺失发生率约为7.8%.单纯性CTD患儿中,PA-VSD,DORV及TOF比TGA更易发生染色体22q11.2微缺失.应加强对单纯性CTD患儿的遗传筛查及咨询.     

Frequency of 22q11.2 microdeletion in children with congenital heart defects in western poland

Background

The 22q11.2 microdeletion syndrome (22q11.2 deletion syndrome -22q11.2DS) refers to congenital abnormalities, including primarily heart defects and facial dysmorphy, thymic hypoplasia, cleft palate and hypocalcaemia. Microdeletion within chromosomal region 22q11.2 constitutes the molecular basis of this syndrome. The 22q11.2 microdeletion syndrome occurs in 1/4000 births. The aim of this study was to determine the frequency of 22q11.2 microdeletion in 87 children suffering from a congenital heart defect (conotruncal or non-conotruncal) coexisting with at least one additional 22q11.2DS feature and to carry out 22q11.2 microdeletion testing of the deleted children's parents. We also attempted to identify the most frequent heart defects in both groups and phenotypic traits of patients with microdeletion to determine selection criteria for at risk patients.

Methods

The analysis of microdeletions was conducted using fluorescence in situ hybridization (FISH) on metaphase chromosomes and interphase nuclei isolated from venous peripheral blood cultures. A molecular probe (Tuple) specific to the HIRA (TUPLE1, DGCR1) region at 22q11 was used for the hybridisation.

Results

Microdeletions of 22q11.2 region were detected in 13 children with a congenital heart defect (14.94% of the examined group). Microdeletion of 22q11.2 occurred in 20% and 11.54% of the conotruncal and non-conotruncal groups respectively. Tetralogy of Fallot was the most frequent heart defect in the first group of children with 22q11.2 microdeletion, while ventricular septal defect and atrial septal defect/ventricular septal defect were most frequent in the second group. The microdeletion was also detected in one of the parents of the deleted child (6.25%) without congenital heart defect, but with slight dysmorphism. In the remaining children, 22q11.2 microdeletion originated de novo.

Conclusions

Patients with 22q11.2DS exhibit wide spectrum of phenotypic characteristics, ranging from discreet to quite strong. The deletion was inherited by one child. Our study suggests that screening for 22q11.2 microdeletion should be performed in children with conotruncal and non-conotruncal heart defects and with at least one typical feature of 22q11.2DS as well as in the deleted children's parents.     

Chromosome 22q11.2 microdeletion in children with conotruncal heart defects: frequency,associated cardiovascular anomalies,and outcome following cardiac surgery

The association of conotruncal heart defects with 22q11.2 chromosomal microdeletions is well established. However, it is not clear whether particular types of conotruncal malformations or additional cardiovascular anomalies are associated with microdeletions. In addition, cardiac surgery outcome in children with conotruncal defects and del22q11.2 is not well described. We prospectively enrolled 214 children with conotruncal defects: 126 with tetralogy of Fallot (TOF), 18 with pulmonary atresia-ventricular septal defect (PA-VSD), 15 with truncus arteriosus communis (TAC) type I, one with interrupted aortic arch (IAA) type B, and 54 with the transposition of great arteries, who were consecutively hospitalized at the Pediatric Cardiology Department between 2003 and 2005. 22q11.2 microdeletion was identified by fluorescence in situ hybridization. The postoperative course following cardiac surgery was compared in patients with TOF and its more severe form, PA-VSD, with/without del22q11.2 (groups A and B) and TAC with/without del22q11.2 (groups C and D). In 15 of 214 patients, 22q11.2 microdeletion was diagnosed (in 11 with TOF/PA-VSD, in three with TAC, in one with IAA type B). In patients with TOF/PA-VSD and microdeletion anatomic features that were significantly associated with 22q11.2, deletion included right aortic arch (p = 0.018), aberrant right subclavian artery (p < 0.001), and major aortopulmonary collateral arteries (p = 0.016). A complicated postoperative course was more frequent and mortality was higher in patients with conotruncal defects and with/without microdeletion. We conclude that additional cardiovascular anomalies are significantly more frequent in children with 22q11.2 microdeletion and TOF/PA-VSD. Children with conotruncal heart defects and 22q11.2 microdeletion more frequently experienced complicated postoperative course after cardiac surgery.     

单纯性圆锥动脉干畸形患者染色体22q11.2微缺失的研究

目的：心血管畸形是22q11.2缺失综合征常见的临床表现,随着研究的深入,该综合征发生率逐渐提高。该文就单纯性心脏圆锥动脉干畸形患者染色体22q11.2微缺失发生率进行研究。方法：对24例单纯型圆锥动脉干畸形患者,包括2例永存动脉干,5例肺动脉闭锁/室间隔缺损,13例法洛四联症,4例右室双出口进行22q11.2内位点DNA探针荧光原位杂交（FISH）检测。结果：24例单纯性圆锥动脉干畸形患者中仅1例患者有22q11.2缺失,发生率为4.2%,低于以往报道。结论：尽管22q11.2缺失在伴其他系统异常的心脏圆锥动脉干畸形患者中较常见,单纯性圆锥动脉干畸形患者很少发现该缺失。［中国当代儿科杂志,2009,11（1）：25-28］     

Chromosome 22q11 microdeletion and congenital heart disease – a survey in a paediatric population

Congenital heart disease is a common finding in patients with microdeletion of chromosome 22q11. To determine if the deletion is an epidemiologically important cause of congenital heart disease, we studied a consecutive series of children attending a paediatric cardiac clinic and of neonates diagnosed as having structural congenital heart disease. Venous blood samples were tested by fluorescent in-situ hybridisation analysis for microdeletion of chromosome 22q11 using probe D22S75. Each patient was examined for the other clinical features associated with microdeletion of chromosome 22q11, and any family history of congenital heart disease recorded. Of 151 families approached, 111 participated and a fluorescent in-situ hybridisation result achieved in 87. One patient with microdeletion of chromosome 22q11 was identified; the clinical features were those of DiGeorge syndrome. Two patients with CHARGE association, two with nasal speech, ten with high arched palate, and 15 with minor facial dysmorphic features had no deletion. Conclusion Microdeletion of chromosome 22q11 detected by probe D22S75 is rare in this consecutive series of patients with structural congenital heart disease. Received: 31 January 1998 / Accepted in revised form: 24 September 1998     

筛查染色体22q11.2缺失综合征在先天性心血管畸形中的意义

染色体22q11.2缺失综合征(22q111DS)又称DiGeorge综合征、腭-心-面综合征,临床表现极具多样性,可累及心血管、免疫系统、面容、内分泌系统,甚至语言发育、精神等多方面.荧光原位杂交能够检测到染色体22q11.2缺失.目前国内对本病认识尚不足,尚未建立规范的临床筛查体系,确诊率亦低.已报道的22q11D...     

筛查染色体22q11.2缺失综合征在先天性心血管畸形中的意义

染色体22q11.2缺失综合征(22q111DS)又称DiGeorge综合征、腭-心-面综合征,临床表现极具多样性,可累及心血管、免疫系统、面容、内分泌系统,甚至语言发育、精神等多方面.荧光原位杂交能够检测到染色体22q11.2缺失.目前国内对本病认识尚不足,尚未建立规范的临床筛查体系,确诊率亦低.已报道的22q11DS病例中,先天性心血管畸形尤其是圆锥干畸形和主动脉弓畸形发生率很高,也最确切.该文拟综述22q11DS,并分析如何在临床工作中从心血管畸形入手早期发现22q11DS,从而早期干预治疗、综合评估、长期随访及遗传咨询,提高患者及后代生活质量.     

NEOPLASTIC DISEASE AND DELETION 22q11.2: A MULTICENTRIC STUDY AND REPORT OF TWO CASES

Deletion 22q11.2 is a chromosomal abnormality detected in young patients with clinical manifestations of the DiGeorge/velocardiofacial syndrome. Conotruncal heart defects are also associated with del22q11.2. An association of these cardiac malformations with neoplasias has been observed. Our series includes two cases of malignancies, a hepatoblastoma and a renal-cell carcinoma, arising in children with complex cardiac malformations. The aim of the study was to determine if the deletion at 22q11.2 was present and could be responsible for both pathological processes. Del22q11.2 was identified in both cases. Comparative genomic hybridization revealed terminal gains on chromosomes 1q and Xq and terminal loss on 1p in the hepatoblastoma, and gains in 1p, 12q, 16p, 20q, 22q, and whole chromosome 19 and loss of Xq in the renal-cell carcinoma. Our results confirm a common genetic basis for cardiac malformations, and del22q11.2 presents a risk factor for the development of pediatric tumours.     

Influence of Chromosome 22q11.2 Microdeletion on Postoperative Calcium Level After Cardiac-Correction Surgery

One of the most common constitutional chromosomal abnormalities, 22q11.2 microdeletion (del22q11.2) syndrome has diverse medical complications, such as congenital heart defect, hypocalcaemia, and immune deficiency, which require coordinated multidisciplinary care. Until now, the natural history of hypocalcaemia in chromosome del22q11.2 syndrome had been only partly documented, but there has been limited recognition of the importance of calcium status during the postoperative period when altered calcium status may be associated with serious complications. The goals of our study were (1) to delineate the clinical characteristics of serum calcium in patients with del22q11.2 during the postoperative period and (2) to make recommendations for the investigation and management of del22q11.2 patients after cardiac correction. This study included 22 children diagnosed with del22q11.2 syndrome and 110 children without del22q11.2 syndrome from Nanjing Children's Hospital. Clinical examinations and blood ionized calcium testing were reviewed retrospectively. A comparative study of postoperative calcium levels and complications of del22q11.2 patients with nondeletion patients was performed. Association between postoperative hypocalcaemia and adverse incidents after cardiac correction was also examined. Postoperative hypocalcaemia was observed among 86.4% of del22q11.2 patients and among only 47.3% of nondeletion subjects. The difference was statistically significant (P?=?0.0017). Patients with del22q11.2 syndrome also had a much sharper decrease in serum calcium levels during the first 6?h after surgery than nondeletion patients. Postoperative clinical analysis showed that del22q11.2 patients with hypocalcaemia experience more postoperative complications (18 of 19) and greater mortality (5 of 19) after cardiac correction than del22q11.2 patients without normal calcium levels and nondeletion patients. Del22q11.2 children have high susceptibility of hypocalcaemia during the postoperative period, and this low calcium status after cardiac correction may be associated with significant risk of postoperative complications and mortality in patients with del22q11.2.     

22q11.2 deletion syndrome: DiGeorge, velocardiofacial, and conotruncal anomaly face syndromes.

A microdeletion of chromosome 22q11.2 is found in most patients with velocardiofacial syndrome, DiGeorge syndrome, and conotruncal anomaly face syndrome, and in some patients with Cayler cardiofacial and autosomal dominant Opitz-G/BBB syndromes. A wide spectrum of clinical findings accompanies the 22q11.2 deletion, without genotype or phenotype correlation even among affected family members. Classic features are dysmorphic facies, conotruncal cardiac defects, hypocalcemic hypoparathyroidism, T-cell mediated immune deficiency, and palate abnormalities. Less well recognized are learning, speech, feeding, and psychiatric disorders, and renal and musculoskeletal defects. Parathyroid and immune deficiencies in the same individual can progress or resolve with time. The 22q11.2 deletion can be inherited as an autosomal dominant or arise as a de novo deletion or translocation. Fluorescent in situ hybridization using cosmid probes mapping to the DiGeorge chromosomal region is a widely available method to detect the 22q11.2 deletion in metaphase chromosomes from cultured lymphocytes, amniocytes, or chorionic villi. The ubiquitin-fusion-degradation-1-like gene, expressed in embryonic branchial arches and in the conotruncus, appears to play a prominent role in the pathogenesis of the 22q11.2 deletion syndrome.     

多重连接依赖的探针扩增技术检测先天性心脏病患儿的22q11微缺失

目的 检测先天性心脏病患儿的22q11微缺失情况.方法 采用商品化的多重连接依赖探针扩增(Multiplex ligation dependent probe amplification,MLPA)P250试剂盒,检测100例散发的先天性心脏畸形样本,其中40例产前超声诊断为心脏畸形的胎儿,60例为先天性心脏病患儿.结果 心脏畸形的胎儿有2例为22q11微缺失,先天性心脏病患儿有1例22q11微缺失;3例检测出22q11微缺失的患儿,2例为3M典型缺失,1例为非典型缺失.结论 在先天性心脏病患儿中存在22q11微缺失.

Abstract：

Objective To detect 22q11 microdeletion in the children and fetuses affected by congenital heart defects.Method MLPA P250 kit was used to detect 22q1 1 microdeletion in 100 cases of sporadic congenital heart defects including 40 fetuses and 60 patients diagnosed by ultrasound.Result Two cases from the fetuses and 4 case from the patients were found to have 22q11 microdeletion.Conclusion Three cases had 22q11 microdeletion in the congenital heart defects.     

DiGeorge syndrome, a review of 52 patients]

The deletion of chromosome 22q11.2 is involved in the majority of DiGeorge or velo-cardiofacial syndrome. The phenotypic variability was noted in the "CATCH 22" acronym. This acronym doesn't recapitulate the full spectrum of the symptoms. The diagnosis of this syndrome can be done with the prenatal diagnosis, with fetal pathology or with a child alive. METHODS: Review of 52 cases with the microdeletion 22q11. Six cases were diagnosed during the prenatal period, 12 cases at fetal pathology examination, and 34 cases during infancy. RESULTS: Cardiac malformations were the major indications (75%) to search for the microdeletion. The facial dysmorphy was difficult to diagnose during the antenatal period or in dead foetus, thereby it was not often recognized. The renal anomalies usually present in 35% of cases, were diagnosed in only 6 to 16% of the cases in our study. CONCLUSION: Phenotypic diversity of the DiGeorge syndrome is important. Its knowledge allows to better determine the indications of the research of the microdeletion. 22q11.2.     

C1-2 vertebral anomalies in 22q11.2 microdeletion syndrome

BACKGROUND: Chromosome 22q11.2 microdeletion syndrome (22q11DS) is characterized by cleft palate, cardiac anomalies, characteristic facies, high prevalence of skeletal anomalies and learning disability. OBJECTIVE: To evaluate the prevalence of craniovertebral junction anomalies in children with 22q11DS and compare these findings to those in nonsyndromic children with velopharyngeal insufficiency (VPI). MATERIALS AND METHODS: Sequential CT scans performed for presurgical carotid assessment in 76 children (45 children positive for chromosome 22q11.2 deletion and 31 negative for the deletion) with VPI were retrospectively evaluated for assessment of C1-2 anomalies. RESULTS: C1-2 vertebral anomalies, specifically midline C1 defects, uptilted or upswept posterior elements of C2 and fusions of C2-3, were nearly universal in our cohort of 22q11DS patients with VPI. They were strikingly absent in the majority of non-22q11DS patients with VPI. CONCLUSION: C1-2 vertebral anomalies, particularly those listed above, are important radiographic markers for 22q11DS.     

Laterality of the aortic arch and anomalies of the subclavian artery—reliable indicators for 22q11.2 deletion syndromes?

A variety of cardiac defects, encompassing truncus arteriosus, tetralogy of Fallot, pulmonary atresia with ventricular septal defect and interrupted aortic arch, are generally summarised as conotruncal malformations. Patients with these cardiac defects were frequently found to have a common microdeletion on chromosome 22, the so-called monosomy 22q11.2. The aim of our study was to determine whether the laterality of the aortic arch or the presence of subclavian artery anomalies (SAA) represent markers for monosomy 22q11.2 in these patients. 170 patients with these cardiac anomalies were recruited at presentation in the paediatric cardiology units of two tertiary referral centres from 1994 until 2003. Of the 170 children and young adults, 33 had interrupted aortic arch, 35 tetralogy of Fallot, 31 truncus arteriosus communis and 71 pulmonary atresia with ventricular septal defect. All were screened for monosomy 22q11.2 and the results were correlated with the laterality of the aortic arch and the presence of SAA contralateral to the aortic arch (aberrant origin from the descending aorta, isolation, distal ductal origin from the pulmonary artery and cervical origin of the right subclavian artery). Monosomy 22q11.2 was present in 59/170 patients (35%). A left aortic arch (LAA) was found in 118 (69%), a right aortic arch (RAA) in 52 (31%) patients. Almost 50% of the patients with RAA (46%), but only 30% of the patients with LAA had monosomy 22q11.2 (P=0.054). A total of 47 patients (28%) had an anomaly of the subclavian artery, 81% of whom had monosomy 22q11.2. This deletion was found in decreasing percentage in patients with LAA+SAA (85%) >RAA+SAA (75%) >RAA without SAA (28%) >LAA without SAA (13%). Conclusion:In patients with conotruncal malformations, anomalies of the subclavian arteries are the most important anatomical marker for the presence of monosomy 22q11.2, independent of the laterality of the aortic arch. Therefore, we recommend cytogenetic testing for this microdeletion in all patients with subclavian artery anomalies and conotruncal malformations.     

Investigating 22q11.2 Deletion and Other Chromosomal Aberrations in Fetuses With Heart Defects Detected by Prenatal Echocardiography

Congenital heart disease (CHD) is the most common birth defect and the leading cause of mortality in the first year of life. In fetuses with a heart defect, chromosomal abnormalities are very frequent. Besides aneuploidy, 22q11.2 deletion is one of the most recognizable chromosomal abnormalities causing CHD. The frequency of this abnormality varies in nonselected populations. This study aimed to investigate the incidence of the 22q11.2 deletion and other chromosomal alterations in a Brazilian sample of fetuses with structural cardiac anomalies detected by fetal echocardiography. In a prospective study, 68 fetuses with a heart defect were evaluated. Prenatal detection of cardiac abnormalities led to identification of aneuploidy or structural chromosomal anomaly in 35.3% of these cases. None of the fetuses with apparently normal karyotypes had a 22q11.2 deletion. The heart defects most frequently associated with chromosomal abnormalities were atrioventricular septal defect (AVSD), ventricular septal defect (VSD), and tetralogy of Fallot. Autosomal trisomies 18 and 21 were the most common chromosomal abnormalities. The study results support the strong association of chromosome alterations and cardiac malformation, especially in AVSD and VSD, for which a chromosome investigation is indicated. In fetuses with an isolated conotruncal cardiopathy, fluorescence in situ hybridization (FISH) to investigate a 22q11.2 deletion is not indicated.     

4q34.1–q35.2 deletion in a boy with phenotype resembling 22q11.2 deletion syndrome

Small terminal or interstitial deletions involving bands 4q34 and 4q35 have been described in several patients with a relatively mild phenotype such as mild to moderate intellectual disability and minor dysmorphic features. We present a boy born from unrelated parents with a de novo 4q34.1–q35.2 deletion and clinical features resembling 22q11.2 deletion syndrome. To the best of our knowledge, this is the first reported patient with 4q34–q35 deletion and phenotype resembling 22q11.2 deletion syndrome without fifth finger anomalies as a specific feature of 4q- syndrome. G-banding karyotyping disclosed the deletion, which was further delineated by microarray comparative genomic hybridization. Fluorescence in situ hybridization and multiplex ligation-dependent probe amplification analyses did not reveal rearrangements of 22q11.2 region. MLPA confirmed the deletion within the 4q35.2 region. Conclusion: Given the considerable clinical overlaps between the 22q11.2 deletion syndrome and clinical manifestation of the patient described in this study, we propose that region 4q34.1–q35.2 should be considered as another region associated with phenotype resembling 22q11.2 deletion syndrome. We also propose that distal 4q deletions should be considered in the evaluation of patients with phenotypic manifestations resembling 22q11.2 deletion syndrome in whom no 22q11.2 microdeletion was detected, even in the absence of distinctive fifth finger anomalies. Additionally, we underline the importance of applying array CGH that enables simultaneous genome-wide detection and delineation of copy number changes (e.g., deletions and duplications).     

Clinical characteristics of children with hypoparathyroidism due to 22q11.2 microdeletion

The phenotypes of chromosomal 22q11.2 microdeletion are quite variable among individuals and hypoparathyroidism (HP) constitutes a definite portion of the clinical spectrum. For the correct diagnosis and pertinent follow up of the HP children due to del22q11.2, we tried to delineate the clinical characteristics of such patients. By employing fluorescence in situ hybridization (FISH) to all the patients diagnosed as HP in our clinic, ten possessed the 22q11.2 microdeletion. Among them, the incidence of cardiac defect (5/10), recurrent infection (1/10) and cleft palate (1/10) was modest. Additionally, seven of them had been diagnosed as HP during the infantile period, when their facial abnormality and intellectual problem had not become evident. Notably, two patients were complicated by Graves disease, while the association of idiopathic thrombocytopenic purpura was also observed in two girls. Conclusion HP due to del22q11.2 may be misdiagnosed as idiopathic, especially in an infant who lacks apparent complications like cardiac anomaly. They should be closely followed up for auto-immune complications. Received: 11 February 1997 and in revised form: 20 June 1997 / Accepted: 6 July 1997