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.     

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.     

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.     

22q11.2 Deletions in Patients with Conotruncal Defects: Data from 1,610 Consecutive Cases

The 22q11.2 deletion syndrome is characterized by multiple congenital anomalies including conotruncal cardiac defects. Identifying the patient with a 22q11.2 deletion (22q11del) can be challenging because many extracardiac features become apparent later in life. We sought to better define the cardiac phenotype associated with a 22q11del to help direct genetic testing. 1,610 patients with conotruncal defects were sequentially tested for a 22q11del. The counts and frequencies of primary lesions and cardiac features were tabulated for those with and those without a 22q11del. Logistic regression models investigated cardiac features that predicted deletion status in tetralogy of Fallot (TOF). Deletion frequency varied by primary anatomic phenotype. Regardless of the cardiac diagnosis, a concurrent aortic arch anomaly (AAA) was strongly associated with deletion status [odds ratio (OR), 5.07; 95 % confidence interval (CI), 3.66–7.04]. In the TOF subset, the strongest predictor of deletion status was an AAA (OR, 3.14; 95 % CI 1.87–5.27; p < 0.001), followed by pulmonary valve atresia (OR, 2.03; 95 % CI 1.02–4.02; p = 0.04). Among those with double-outlet right ventricle and transposition of the great arteries, only those with an AAA had a 22q11del. However, 5 % of the patients with an isolated conoventricular ventricular septal defect and normal aortic arch anatomy had a 22q11del, whereas no one with an interrupted aortic arch type A had a 22q11del. A subset of patients with conotruncal defects are at risk for a 22q11del. A concurrent AAA increases the risk regardless of the intracardiac anatomy. These findings help to direct genetic screening for the 22q11.2 deletion syndrome in the cardiac patient.     

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.     

Genetic analyses in two extended families with deletion 22q11 syndrome: importance of extracardiac manifestations

OBJECTIVES: Cardiovascular malformations (CVMs) are reported to be common (approximately 75%) in patients with deletion 22q11.2 (del22q11) syndrome. To better understand why deletions go unrecognized, we characterized the phenotype in deleted individuals in two large kindreds with particular emphasis on the presence or absence of CVM. STUDY DESIGN: After the diagnosis of del22q11 in two unrelated probands with CVM, we sequentially evaluated family members with clinical evaluation and cytogenetic analysis. RESULTS: Del22q11 was identified in 13 individuals; all exhibited characteristic dysmorphic facial features, but a CVM was present in only 6 of 13 (46%) individuals. CONCLUSIONS: We speculate that in the absence of CVM, diagnosis of del22q11 is hampered by a failure to recognize extracardiac features of the del22q11 syndrome spectrum. The data highlight the need for primary care physicians and specialists to familiarize themselves with the extracardiac stigmata of del22q11 to ensure timely diagnosis in all family members.     

Velofacial hypoplasia (Sedlackova syndrome): a variant of velocardiofacial (Shprintzen) syndrome and part of the phenotypical spectrum of del 22q11.2

In 1955, a pattern of velar hypoplasia causing hypernasal speech and associated facial dysmorphism was observed in 26 children of Czech origin. Further cases with submucous cleft and/or cardiac anomalies were described. In 1978 velocardiofacial syndrome (VCFS) was reported, a condition very similar to velofacial hypoplasia (Sedlackova syndrome) apart from overt clefts instead of velar hypoplasia. In 1990 it was suggested that both syndromes might be variants of the same clinical entity. To test this hypothesis we performed fluorescence in situ hybridisation using the DiGeorge/VCFS region specific probe D22S75 on 20 patients originally classified as Sedlackova syndrome as well as molecular investigations for a subset of these patients. A 22q11.2 deletion was found in 16/20 patients. Thus, our results confirm the aforementioned hypothesis and expand the long list of clinical diagnoses associated with del 22q11.2. CONCLUSION: Velofacial hypoplasia (Sedlackova syndrome) and velocardiofacial (Shprintzen) syndrome have a corresponding phenotype and are both associated with del 22q11.2.     

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     

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.     

Two cases of 22q11.2 deletion syndrome with anorectal anomalies and growth retardation

Clinical features associated with the deletion of 22q11.2 are highly variable. Most are diagnosed by cardinal congenital heart disease or hypoparathyroidism. In cases without major features, an early accurate diagnosis of 22q11.2 deletion syndrome is difficult. Congenital anorectal malformations (ARM), which can be detected soon after birth, have been rarely reported in 22q11.2 deletion syndrome. We report two cases of 22q11.2 deletion syndrome with ARM who showed growth retardation. ARM was detected in both patients without congenital heart disease or hypoparathyroidism at early infancy and they were followed by pediatric surgeons. Later, failure to thrive or short stature became evident, and they consulted with pediatric endocrinologists who subsequently confirmed the diagnosis of 22q11.2 deletion by fluorescent in situ hybridization analysis. The combination of ARM and growth retardation may lead to an early diagnosis of 22q11.2 deletion syndrome.     

An adolescent with 22q11.2 deletion syndrome and multiple endocrinopathies

The endocrine abnormalities are common in patients with 22q11.2 deletion, and include hypocalcaemia due to primary hypoparathyroidism, short stature and thyroid dysfunction. We present a patient with delayed diagnosis of del22q11.2 who had multiple endocrine involvement and type 1 diabetes mellitus. A review is also made on the current knowledge of the endocrine manifestations described in patients with 22q11.2 deletion.     

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.     

Cytogenetic Findings in Pediatric T-Lymphoblastic Lymphomas: One Institution’s Experience and a Review of the Literature

Cytogenetic analyses of lymphomas commonly reveal nonrandom chromosomal abnormalities, but there are relatively few reports in childhood lymphoblastic lymphoma (LL). We retrospectively reviewed G-banded karyotypic analyses performed at Arkansas Children’s Hospital between 1990 and 2004. Six children (2 to 20 years old) had LL that presented as mediastinal or cervical masses and had a T-cell immunophenotype and clonal abnormalities. The cytogenetic findings in these 6 patients were as follows: 46,XX,?7,inv(9)(p11q12),der (12)t(7;12)(q11.2;p13),t(16;18)(p13.1;q21),+22 in patient 1; 47,XX,+9,del(9)(q11q22)x2 in patient 2; 72?119, XY,+X,+1,+1, inv(2) (p11q13),?3,+5,+6,+7,+10,?12,?16, ?21,?21,?22,+mar in patient 3; 48,XY,+5,+20,t(7;9) (q32;q34) in patient 4; 47～48,XX,der(10)t(10;14)(q23; q11.2),+12, del(12)(p12)x2, ?14,del(16)(q22q22),+?add (19)(p13.3) in patient 5; and 48～49,XY,+7,+8,t(11;19) (q23;p?13.3),+der(19)t(11;19)[cp20] in patient 6. Eleven chromosome breakpoints in 6 of our patients (7q11, 12p13, 16p13, 18q21, 9q11, 2p11, 2q13, 7q32, and 7q23) have been reported in other patients with acute lymphoblastic leukemia or LL and involved regions containing TEL, ABL, E2A, MLL, and T-cell receptor-α genes. A review of the cytogenetic findings of these and other cases of LL reveals that clonal aberrations are common and most frequently involve T-cell receptor gene regions. The aberrations show some features similar to those of acute lymphoblastic leukemia and are not unique to LL, thus furnishing additional evidence of the equivalence of these two diseases. The cytogenetic features of LL may be helpful in the diagnosis of pediatric lymphomas and undifferentiated neoplasms.     

Novel translocation in acute megakaryoblastic leukemia (AML-M7)

The authors report a unique translocation in a patient with M7 acute myeloid leukemia and review the literature. A 22-month-old girl without Down syndrome was diagnosed with acute myeloid leukemia, subtype M7 (AML-M7), and died with relapsed disease following bone marrow transplantation. Tumor cells were evaluated using cytogenetics (including spectral karyotyping), immunohistochemistry, and flow cytometry. The patient was found to have a previously unreported complex translocation as follows: 50,XX,der(1)t(1;5)(p36?.1;p15?.1),del(5)(p15?.1), +6,+der(6;7)(?;?),der(7)t(6;7)(?;p22)[2],der(9)t(6;9) (?;p21)t(9;14)(q34;q11.2-q13),+10,t(12;16)(p13;q24),-14[2], del(14)(q13)[2],+der(19)t(1;19)(?;p13.3),+22[cp 4]. AML-M7 in non-Down syndrome patients is a rare disease that requires improved prognostic markers.     

Reproductive failure in a carrier of inv dupl l(q21.4----q12)

High resolution analysis of the early metaphase and prometaphase chromosomes of the father of a child with malformations and mental retardation revealed inv dupl l(q21.4----q12). Almost the same was the aberration in the propositus but with a deletion of the band lq11.2 : 46,XX, inv dupl l(q21.4----q12)del lq11.2. This suggested that the malformations and mental retardation in the child were probably due to the microchromosome anomaly in the euchromatin, connected with the heterochromatin block in the father.     

Defining new guidelines for screening the 22q11.2 deletion based on a clinical and dysmorphologic evaluation of 194 individuals and review of the literature

The 22q11.2 deletion is the most frequent interstitial deletion in humans and presents a wide phenotypic spectrum, with over 180 clinical manifestations described. Distinct studies have detected frequencies of the deletion ranging from 0 % to 75 %, depending on the studied population and selection criteria adopted. Due to the lack of consensus in this matter, several studies have been conducted aiming to define which patients would be eligible for screening; however, the issue is still up for debate. In order to contribute to the delineation of possible clinical and dysmorphologic guidelines to optimize decision making in the clinical setting, 194 individuals with variable features of the 22q11.2 deletion syndromes (22q11.2DS) were evaluated. Group I, clinical suspicion of 22q11.2DS with palatal anomalies; Group II, clinical suspicion without palatal anomalies; Group III, cardiac malformations associated with the 22q11.2DS; and Group IV, juvenile-onset schizophrenia. Multiplex ligation-dependent probe amplification was used for screening the 22q11.2 deletion, which was detected in 45 patients (23.2 %), distributed as such: Group I, 35/101 (34.7 %); Group II, 4/18 (22.2 %); Group III, 6/52 (11.5 %); and Group IV, 0/23 (0 %). Clinical data were analyzed by frequency distribution and statistically. Based on the present results and on the review of the literature, we propose a set of guidelines for screening patients with distinct manifestations of the 22q11.2DS in order to maximize resources. In addition, we report the dysmorphic features which we found to be statistically correlated with the presence of the 22q11.2DS.     

Impact of 22q11.2 Deletion on the Postoperative Course of Children After Cardiac Surgery

The primary objective of this study was to describe the impact of 22q11.2 deletion (del22q11) on the clinical characteristics, postoperative course, and short-term outcomes of children undergoing surgery for congenital heart disease. The charts of all children ages 1 day–18 years who received cardiac surgery for interrupted aortic arch (IAA), tetralogy of Fallot (TOF), or truncus arteriosus (TA) repair from 1 January 2001 to 31 December 2011 were retrospectively reviewed. The patients were divided into two groups: the 22q11 group including children with del22q11 undergoing surgery for TOF, IAA, or TA and the non-22q11 or control group including children with no chromosomal or genetic abnormality undergoing surgery for TOF, IAA, or TA. Demographic information, cardiac diagnoses, noncardiac abnormalities, preoperative factors, intraoperative details, surgical procedures performed, postoperative complications, and in-hospital deaths were collected. The outcome data collected included days of inotrope use, need for dialysis, length of mechanical ventilation, intensive care unit (ICU) length of stay (LOS), hospital LOS, and mortality. The study enrolled 173 patients: 65 patients in the 22q11 group and 108 patients in the control group. Of the 65 patients in the 22q11 group, 36 (55 %) underwent repair for TOF, 13 (20 %) for IAA, and 16 (25 %) for TA. The two groups did not differ in terms of age or weight. The preexisting conditions were similar in the two groups. Unplanned noncardiac operations were more common in the children with del22q11, but delayed chest closure was similar in the two groups. The incidence of postoperative noncardiac complications such as reintubation, vocal cord paralysis, and diaphragmatic paralysis was similar in the two groups. However, increasing numbers of patients in del22q11 group needed dialysis in one form or the other during the immediate postoperative stay. The incidence of fungal infection and wound infection was higher in the del22q11 group than in the control group. Duration of mechanical ventilation, ICU LOS, and hospital LOS were similar in the two groups, except in certain subgroups. Mortality did not differ significantly between the two groups. In conclusion, children with del22q11 have a higher risk of postoperative complications after cardiac surgery, with no difference in length of mechanical ventilation, ICU LOS, hospital LOS, or mortality. However, short-term outcomes may differ in certain subgroups.     

Hypocalcemia impacts heart failure control in DiGeorge 2 syndrome

Chromosome 10p terminal deletion accounts for a rare subset among patients presenting with DiGeorge syndrome, and is designated as DiGeorge 2 syndrome. We report a neonate with DiGeorge-like phenotype having a deletion of distal 10p (p13-pter) and a duplication of terminal 3q (q29-qter) derived from paternal balanced translocation between 3q29 and 10p13. She had facial dysmorphism, atrial and ventricular septal defect, impaired T-cell function, hypoparathyroidism, sensorineural hearing loss, renal abnormalities and developmental delay. Her phenotype corresponded well with the typical characteristics of partial monosomy 10p and the small duplication of terminal 3q did not involve the critical region of 3q duplication syndrome. Clinically, hypoparathyroidism-related hypocalcemia lasted for three weeks and resulted in repeated episodes of heart failure. It was not until the calcium level was normalized that her heart failure improved markedly.
Conclusion: Cytogenetic analysis can help to recognize patients early on who have terminal 10p deletion when microdeletion of 22q11.2 is not the cause of DiGeorge syndrome. Hypoparathyroidism-related hypocalcemia impacts heart failure control in partial monosomy 10p and should be managed aggressively on critical care.     

Left Ventricular Noncompaction and Coronary Artery Fistula in an Infant with Deletion 22q11.2

This report describes an infant presenting with deletion 22q11.2 in combination with left ventricular noncompaction and a coronary artery fistula. These two cardiac findings have rarely been reported in association with each other and have never been reported together in combination with deletion 22q11.2. The reported case demonstrates the expanding cardiac phenotype of individuals with deletion 22q11.2, suggesting that it may be appropriate to offer studies for the detection of deletion 22q11.2 to individuals with a wide range of structural cardiac defects.