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 microdeletion syndrome: cardiorespiratory symptoms and fibrobronchoscopy

The 22q11 deletion syndrome is a frequent contiguous-gene deletion syndrome. This disorder has a broad spectrum of phenotypic manifestations. It includes various syndromes such as DiGeorge syndrome. The most frequent clinical manifestations are congenital cardiac defects, characteristic facies, palate malformations, hypoparathyroidism, immunodeficiency due to thymic hypoplasia, growth retardation, and behavioural and psychiatric problems. Among the symptoms observed, many patients suffer from respiratory insufficiency or failure. The origin is often multifactorial. Structural airway abnormalities are frequently found in this syndrome. In many of these patients the malformation is mild or non-existent, and remains asymptomatic. However, in some cases it can cause a severe respiratory insufficiency, being diagnosed when other disorders are ruled out. These cases illustrate the importance of early visualisation of the airway by fibrobronchoscopy in the management of the patient with 22q11 deletion syndrome who has recurrent respiratory difficulties.     

Cardiac surgery unmasks latent hypoparathyroidism in a child with the 22q11.2 deletion syndrome

The 22q11.2 deletion syndrome is a developmental field defect of the third and fourth pharyngeal pouches characterized by a spectrum of thymic and parathyroid gland abnormalities and conotruncal cardiac defects. Latent hypoparathyroidism, defined as normocalcaemia at rest but reduced ability to secrete parathyroid hormone (PTH) in response to pharmacologically evoked hypocalcaemia, is found in 30-50% of people with this syndrome. Its natural history is unknown. We describe a 1.5 year-old girl with tetralogy of Fallot, normal calcium metabolism and few facial dysmorphic features who developed transient hypoparathyroidism in the postoperative period, which lasted months and waxed and waned during this observation period. The clinical picture led us to the diagnosis of 22q11.2 deletion syndrome.     

Growth hormone deficiency in patients with 22q11.2 deletion: expanding the phenotype

The list of findings associated with the 22q11.2 deletion is quite long and varies from patient to patient. The hallmark features include: conoruncal cardiac anomalies, palatal defects, thymic aplasia or hypoplasia, T cell abnormalities, mild facial dysmorphia, and learning disabilities. The 22q11.2 deletion has been seen in association with the DiGeorge sequence, velocardiofacial syndrome (VCFS), conotruncal anomaly face syndrome, isolated conotruncal cardiac anomalies, and some cases of autosomal dominant Optiz G/BBB syndrome. Short stature has been seen in one to two thirds of children reported in the literature with a diagnosis of VCFS, but growth hormone deficiency (GHD) has not been described in conjunction with this diagnosis. We present 4 patients with a 22q11.2 deletion and short stature who were found to have abnormalities in the growth hormone-insulin-like growth factor I axis. All had growth factors less than -2 SD for age and failed provocative growth hormone testing. Two patients were found to have abnormal pituitary anatomy. In our population, the incidence of GHD in 4 or 95 children with 22q11 deletion is significantly greater than the estimated incidence of GHD in the general population. Children with a 22q11.2 deletion appear to be at a greater risk for pituitary abnormalities. Therefore, those children with the 22q11.2 deletion and short stature or poor growth should be evaluated for GHD, as replacement growth hormone therapy may improve their growth velocity and final height prediction.     

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.     

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目的 探讨22q11.2微缺失综合征患儿的不同临床表现.方法 收集2006年7月至2007年6月在英国Oxford儿童医院临床所见的7例经分子细胞遗传学分析(FISH检测)确诊为22q11.2微缺失综合征患儿的临床资料,分析其临床表现、诊断及治疗情况.结果 7例中男2例,女5例.7例均通过FISH检测确诊,1例为产前诊断,余6例的平均确诊年龄为2个月.2例(28.4%)为父母遗传致病,5例(71.6%)为基因突变致病.其中,先天性心脏病和面容异常的发生率均为100%,免疫功能异常28.6%,颚裂14.3%,低钙14.3%.根据患儿的不同临床表现进行对症治疗.结论 22q11.2微缺失综合征患儿以心脏畸形及面容异常为突出表现,结合FISH检测可早期诊断,基因突变是其主要病因,以流出道受损为主的心脏畸形及以T淋巴细胞数量减少为主的免疫功能异常是影响预后的关键因素.     

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.     

Growth hormone deficiency associated with 22q11.2 deletion: a case report

The 22q11.2 microdeletion produces many syndromes, characterized by similar phenotypical features. The most known syndromes are: the DiGeorge syndrome, the velocardiofacial syndrome, the conotruncal anomaly face syndrome. The hallmark features are represented by cardiac anomalies, palate defects, immune and cognitive deficiencies, facial dysmorphisms. Less common disorders include: genito-urinary abnormalities, visual defects, autoimmune disorders and pituitary anomalies, being the last represented by growth hormone and/or insulin growth factor-I deficiency. We present the case of a 8 years old male admitted to our Division for failure to thrive. We found growth hormone deficiency and pituitary hypoplasia associated with some of the anomalies shown above, thus we suspected and confirmed the 22q11.2 deletion syndrome. In literature few cases of associated 22q11.2 deletion syndrome with growth hormone deficiency are described, while short stature between children with and children without cleft palate is reported to be more frequent in the first ones, suggesting that the 22q11.2 deletion syndrome remains undetected in many affected children and that the growth hormone deficiency prevalence in affected children has to be investigated. The wide phenotypical presentation of 22q11.2 deletion syndrome requires a multidisciplinary approach to the affected subject and, from the auxologic point of view, is good to monitoring the growing trend and, if short stature is present, check for the growth hormone deficiency.     

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.     

4号染色体4q21/q22缺失综合征1例报告

目的提高对4q21/q22缺失综合征的临床和基因特征的认识。方法回顾性分析1例有特殊面容及体格智力发育迟缓患儿的临床资料及基因检测结果。结果患儿,女,2个月。表现为喂养困难,发育迟缓,新生儿期肌张力低下,头大,前额及枕部突出,小手足;合并先天性心脏病。应用染色体微阵列芯片分析技术发现患儿4q21.21q22.2区域有一缺失,缺失片段大小约15.26 Mb,至少包含76个基因,确诊为4q21/q22缺失综合征。结论患儿有典型面容特征,发育迟缓,伴其他系统累及时应考虑4q21/q22缺失综合征可能,染色体芯片检测技术有助于明确诊断。     

Immunologic features of chromosome 22q11.2 deletion syndrome (DiGeorge syndrome/velocardiofacial syndrome).

OBJECTIVES: To characterize immunologic function and clinical characteristics in patients with chromosome 22q11.2 deletion syndrome and determine whether there was significant change over time. METHODS: This study characterized the laboratory and clinical features of the immunodeficiency in a cohort of 195 patients with chromosome 22q11.2 deletion syndrome and used cross-sectional and analysis of variance to compare the findings in different age groups with control patients. Changes over time were also characterized by a model effect method in a subset of patients who were studied serially. RESULTS: Diminished T cell counts in the peripheral blood are common in patients with chromosome 22q11.2 deletion syndrome. The pattern of changes seen with aging in normal control patients was also seen in patients with chromosome 22q11.2 deletion syndrome, although the decline in T cells was blunted. Autoimmune disease was seen in most age groups, although the types of disorders varied according to age. Infections were also common in older patients, though they were seldom life threatening. CONCLUSIONS: Slow declines in T cell populations are seen in chromosome 22q11.2 deletion syndrome. Clinical manifestations of immunodeficiency, such as recurrent infection and autoimmune disease, were common in this population but had little relationship to specific immunologic laboratory features.     

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).     

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     

Velo-cardio-facial syndrome

Velo-cardio-facial syndrome (VCFS) is the most common contiguous gene deletion syndrome in humans, caused by a microdeletion from chromosome 22 at the q11.2 locus. Moreover, it is one of the most common multiple anomaly syndromes associated with congenital heart disease and is certainly the most common syndrome causing conotruncal heart anomalies. The population prevalence of this syndrome is probably increasing because of the advances in the diagnosis and treatment of congenital heart malformations. Presenting symptoms are highly variable because VCFS is often the trigger for a number of developmental malformation sequences, including DiGeorge sequence, Robin sequence, and Potter sequence. Because of the variability of the phenotypic expression of VCFS, the disorder has been delineated in several sets of literature from different areas of specialization, and from publications in the U.S., Eastern Europe, and Japan. The result has been nosologic differences with various names for the same disorder caused by a 22q11.2 deletion, including VCFS, Shprintzen syndrome, DiGeorge syndrome, Sedlačková syndrome, Cayler syndrome, and conotruncal anomalies face syndrome. All of these labels represent exactly the same syndrome. Understanding the cause of the various phenotypes associated with VCFS is dependent on careful studies of genotype to phenoype matching. The deleted region in most cases of VCFS encompasses 3 million base pairs of DNA and 30 genes. The challenge is therefore to determine if the broad spectrum of anomalies are caused by one major gene, most or all of the deleted genes, or the interaction between the genes in the deleted region and other genes elsewhere in the genome. There is some evidence for each of these hypotheses. The ability to complete phenotype to genotype matching is enhanced by the recognition of more cases and the careful study of phenotypic expression. Towards this end, screening of cases with congenital heart disease is imperative and guidelines for screening are discussed.     

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.     

Asymmetric crying facies associated with congenital hypoparathyroidism and 22q11 deletion

Asymmetric crying facies is caused by congenital hypoplasia or agenesis of the depressor anguli oris muscle. Associations of this facial defect with major congenital anomalies have been reported, most commonly in the cardiovascular system and less frequently involving the genitourinary, musculoskeletal, cervicofacial, respiratory, and rarely, the endocrine system. CATCH 22 is a medical acronym for cardiac defects, abnormal facies, thymic hypoplasia, cleft palate and hypocalcemia and a variable deletion on chromosome 22q11. The deletion within chromosme region of 22q11 may occur in patients with dysmorphologic and cardiological syndromes: DiGeorge syndrome, velo-cardiofacial syndrome and conotruncal anomaly face syndrome. We report a newborn infant who had asymmetric crying facies associated with congenital hypoparathyroidism, severe neonatal hypocalcemia and tetralogy of Fallot. Genetic confirmation of chromosome 22q11 deletion was made.     

Transient congenital hypoparathyroidism and 22q11 deletion

CATCH-22 syndrome represents a spectrum of abnormalities associated with microdeletions of chromosome 22q11. We report a patient with transient congenital hypoparathyroidism, with severe neonatal hypocalcemia and spontaneous resolution in infancy, tetralogy of Fallot and thymic hypoplasia. Genetic confirmation of chromosome 22q11 deletion was made. Newborns with congenital hypoparathyroidism need genetic analysis and examination for anomalies associated with CATCH-22 syndrome.     

A search for chromosome 22q11.2 deletions in a series of 176 consecutively catheterized patients with congenital heart disease: no evidence for deletions in non-syndromic patients

Microdeletions in chromosome 22q11.2 are associated with DiGeorge syndrome (DGS), velo-cardio-facial syndrome (VCFS), and several other syndromes, collectively referred to as DG/VCF. Non-dysmorphic patients with cardiac defects have also been attributed to deletions in this chromosomal region. In this study 157 consecutively catheterized patients with isolated, non-syndromic cardiac defects, and 25 patients with cardiac defects and additional stigmata (10 of whom were clinically diagnosed as DG/VCF cases prior to chromosome analysis) were analysed by fluorescence in situ hybridization with the DGS-specific probe D0832. Chromosome 22q11.2 deletions were observed only in the ten patients with the clinical diagnosis of DG/VCF. Conclusion In a large unselected cohort of patients with congenital heart disease no association between isolated or non-syndromic heart defects and the 22q11.2 microdeletion was observed. One can conclude that testing for the 22q11.2 microdeletion is clearly indicated in cases when even mild extracardiac abnormalities are present, particularly in very young infants. Received: 24 February 1998 / Accepted in revised form: 04 May 1999     

A population study of chromosome 22q11 deletions in infancy

AIMS: To determine the prevalence of submicroscopic deletions within chromosome band 22q11 in infants with significant heart disease and compare this with the prevalence of other chromosomal abnormalities causing significant heart disease. To determine a minimum prevalence of deletions within chromosome band 22q11 in infants in the general population. METHODS: Chromosome analysis was performed on samples from infants born in the former UK Northern Health Region in 1994 and 1995 who either had significant heart disease or who were suspected to have a chromosome band 22q11 deletion following referral to the Northern Genetics Service. Significant heart disease was defined as major structural malformation or cases where invasive investigation or intervention was required in infancy. RESULTS: Chromosome band 22q11 deletions were identified in nine infants in a population of 69,129 livebirths, giving a minimum prevalence of 13 per 100,000 (95% confidence interval 4.5 to 21.5). Six cases had significant heart disease, one of whom died before diagnosis. In the same population there were 53 cases of trisomy 21, 15 of whom had significant heart disease. CONCLUSION: The most common chromosomal cause of significant congenital heart disease remains trisomy 21, while the second most common chromosomal cause is deletion in chromosome band 22q11.