Fluorescence in situ hybridization (FISH) screening for the 22q11.2 deletion in patients with clinical features of velocardiofacial syndrome but without cardiac anomalies

A Rare Case of Mosaic Unbalanced Non-Robertsonian Translocation Involving Chromosomes 15 and 22 with Congenital Abnormalities in Monozygotic Twins

Balanced de novo non-robertsonian translocations (non-RTs), which involve acrocentric chromosomes, are rare findings in clinical cytogenetics and may be associated with an abnormal phenotype. These translocations, detected by conventional karyotyping, are found in approximately 1:1,000 neonates. In most of these cases, one of the parents carries the same translocation. In this study, we report a rare non-RT involving chromosomes 15 and 22 defined as 45, XX, -22,der(15;22)t(15;22)/46, XX, der(15)t(15;22),der(22). To our knowledge, this is the first report of a non-RT t(15;22) with these breakpoints.

De novo unbalanced translocation t(15;22)(q26.2;q12) with velo-cardio-facial syndrome: A case report and review of the literature

The present study reports the case of a 3-h old male with a de novo unbalanced t(15;22) translocation and velo-cardio-facial syndrome (VCFS), with other abnormalities. The manifestations of the condition observed in the patient included cleft palate with feeding difficulties, respiratory infection, dysmorphic face with almond-shaped eyes, a long and wide nose, small and low-set ears, tetralogy of Fallot, cryptorchidism and varus equinus. Standard lymphocyte cytogenetic analysis using G-banding demonstrated a 45,XY,-22,der (15),t(15;22)(q26.2;q12) karyotype. Fluorescent in situ hybridization with DiGeorge/VCFS TUPLE 1 confirmed 22q11 deletions. These cytogenetic aspects appear to be rare in the etiology of VCFS, as >1% of all 22q11 deletions are the result of an unbalanced translocation, which involves chromosomes 22 and another chromosome. To the best of our knowledge, this is the second reported case where the clinical features associated with VCFS are combined with an unbalanced (15;22) translocation involving the critical 22q11.2 region.

Caracterização do perfil comportamental e de competência social de indivíduos com a síndrome del22q11.2

Resumo:OBJETIVO:caracterizar os problemas comportamentais e de competência social de indivíduos com a síndrome del22q11.2 e compará-los com indivíduos com desenvolvimento típico, segundo informação dos pais.MÉTODOS:participaram desta pesquisa 24 pais de indivíduos de ambos os gêneros, entre seis e 18 anos, sendo 12 indivíduos com a síndrome del22q11.2 (grupo amostral) e 12 indivíduos com desenvolvimento típico (grupo controle). Foi aplicado o inventário comportamental "Child Behavior Checklist (CBCL)".RESULTADOS:oito dos 12 indivíduos com a síndrome foram classificados como "clínico" nas escalas de comportamento e Problemas Internalizantes; cinco dos 12 indivíduos do grupo amostral foram classificados como "clínico" quanto às escalas de comportamento e Problemas Externalizantes. Nas habilidades de competência social, dez dos 12 indivíduos do grupo amostral foram classificados como "clínico".CONCLUSÃO:indivíduos com diagnóstico da síndrome del22q11.2 apresentaram, segundo opinião dos pais, problemas comportamentais e de competência social, em diferentes graus de comprometimento. Quando realizada a comparação entre os grupos pode-se observar diferenças estatisticamente significantes em variáveis dos comportamentos externalizantes e dos comportamentos internalizantes. Desta forma, concluí-se que o grupo amostral apresenta comportamentos mais alterados quando comparados ao grupo controle.

Classification, epidemiology, and genetics of orofacial clefts

Orofacial clefts (OFCs) include a broad range of facial conditions that differ in cause and disease burden. In the published literature, there is substantial ambiguity in both terminology and classification of OFCs. This article discusses the terminology and classification of OFCs and the epidemiology of OFCs. Demographic, environmental, and genetic risk factors for OFCs are described, including suggestions for family counseling. This article enables clinicians to counsel families regarding the occurrence and recurrence of OFCs. Although much of the information is detailed, it is intended to be accessible to all health professionals for use in their clinical practices.

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.

Characteristic face: a key indicator for direct diagnosis of 22q11.2 deletions in Chinese velocardiofacial syndrome patients

Velocardiofacial syndrome (VCFS) is a disease in human with an expansive phenotypic spectrum and diverse genetic mechanisms mainly associated with copy number variations (CNVs) on 22q11.2 or other chromosomes. However, the correlations between CNVs and phenotypes remain ambiguous. This study aims to analyze the types and sizes of CNVs in VCFS patients, to define whether correlations exist between CNVs and clinical manifestations in Chinese VCFS patients. In total, 55 clinically suspected Chinese VCFS patients and 100 normal controls were detected by multiplex ligation-dependent probe amplification (MLPA). The data from MLPA and all the detailed clinical features of the objects were documented and analyzed. A total of 44 patients (80.0%) were diagnosed with CNVs on 22q11.2. Among them, 43 (78.2%) presented with 22q11.2 heterozygous deletions, of whom 40 (93.0%) had typical 3-Mb deletion, and 3 (7.0%) exhibited proximal 1.5-Mb deletion; no patient was found with atypical deletion on 22q11.2. One patient (1.8%) presented with a 3-Mb duplication mapping to the typical 3-Mb region on 22q11.2, while none of the chromosomal abnormalities in the MLPA kit were found in the other 11 patients and 100 normal controls. All the 43 patients with 22q11.2 deletions displayed characteristic face and palatal anomalies; 37 of them (86.0%) had cognitive or behavioral disorders, and 23 (53.5%) suffered from immune deficiencies; 10 patients (23.3%) manifested congenital heart diseases. Interestingly, all patients with the characteristic face had 22q11.2 heterozygous deletions, but no difference in phenotypic spectrum was observed between 3-Mb and 1.5-Mb deletions. Our data suggest that the characteristic face can be used as a key indicator for direct diagnosis of 22q11.2 deletions in Chinese VCFS patients.

Typical phenotypic spectrum of velocardiofacial syndrome occurs independently of deletion size in chromosome 22q11.2

Velocardiofacial syndrome (VCFS) is a relatively common developmental disorder characterized by craniofacial anomalies and conotruncal heart defects. Many VCFS patients present hemizygous deletions on part of chromosome 22q11.2; suggestive that haploinsufficiency in this region is responsible for this etiology. Most 22q11.2 deletions occur sporadically, although in some cases the deletion may be transmitted. A total of 29 VCFS patients and their parents were genotyped using six consecutive polymorphic markers (STS) of the chromosome 22q11.2: D22S420, D22S941, D22S264, D22S306, D22S425, and D22S257. The results revealed that 72% (21/29) of the patients harbored a deletion involving the polymorphic markers D22S420, D22S941, and/or D22S264. Haplotype analysis showed that among the patients studied, the deletions were either of maternal or paternal origin. Our findings demonstrated that independently of their size, any deletion occurring in the VCFS critical region is enough to confer the patient phenotype.