Williams-Beuren syndrome in Mexican patients confirmed by FISH and assessed by aCGH.

Williams-Beuren syndrome (WBS) has a prevalence of 1/7500-20000 live births and results principally from a de novo deletion in 7q11.23 with a length of 1.5 Mb or 1.8 Mb. This study aimed to determine the frequency of 7q11.23 deletion, size of the segment lost, and involved genes in 47 patients with a clinical diagnosis of WBS and analysed by fluorescence in situ hybridization (FISH); among them, 31 had the expected deletion. Micro-array comparative genomic hybridization (aCGH) confirmed the loss in all 18 positive-patients tested: 14 patients had a 1.5 Mb deletion with the same breakpoints at 7q11.23 (hg19: 72726578-74139390) and comprising 24 coding genes from TRIM50 to GTF2I. Four patients showed an atypical deletion: two had a 1.6 Mb loss encompassing 27 coding genes, from NSUN5 to GTF2IRD2; another had a 1.7 Mb deletion involving 27 coding genes, from POM121 to GTF2I; the remaining patient presented a deletion of 1.2 Mb that included 21 coding genes from POM121 to LIMK1. aCGH confirmed the lack of deletion in 5/16 negative-patients by FISH. All 47 patients had the characteristic facial phenotype of WBS and 45 of 47 had the typical behavioural and developmental abnormalities. Our observations further confirm that patients with a classical deletion present a typical WBS phenotype, whereas those with a high (criteria of the American Association of Pediatrics, APP) clinical score but lacking the expected deletion may harbour an ELN point mutation. Overall, the concomitant CNVs appeared to be incidental findings.

22q11.2 deletion detected by in situ hybridization in Mexican patients with velocardiofacial syndrome-like features.

INTRODUCTION: Deletion 22q11.2 occurs in 1:4,000-1:6,000 live births while 10p13p14 deletion is found in 1:200,000 newborns. Both deletions have similar clinical features such as congenital heart disease and immunological anomalies. OBJECTIVE: We looked for a 22q11.2 deletion in Mexican patients with craniofacial dysmorphisms suggestive of DiGeorge or velocardiofacial syndromes and at least one major phenotypic feature (cardiac anomaly, immune deficiency, palatal defects or development delay). METHODS: A prospective study of 39 patients recruited in 2012-2015 at the Instituto Mexicano del Seguro Social at Guadalajara, Mexico. The patients with velocardiofacial syndrome-like features or a confirmed tetralogy of Fallot (TOF) or complex cardiopathy were studied by G-banding and fluorescence in situ hybridization (FISH) with a dual TUPLE1(HIRA)/ARSA or TUPLE1(22q11)/22q13(SHANK3) probe, six patients without the 22q11.2 deletion (arbitrarily selected) were tested with the dual DiGeorge II (10p14)/D10Z1 probe. RESULTS: Twenty-two patients (7 males and 15 females) had the 22q11.2 deletion and 17/39 did not have it; no patient had a 10p loss. Among the 22 deleted patients, 19 had congenital heart disease (mostly TOF). Twelve patients without deletion had heart defects such as TOF (4/12), isolate ventricular septal defect (2/12) or other disorders (6/12). CONCLUSION: In our small sample about ~56% of the patients, regardless of the clinical diagnosis, had the expected 22q11.2 deletion. We remark the importance of early cytogenetic diagnosis in order to achieve a proper integral management of the patients and their families.

INTRODUCCIÓN: La deleción 22q11.2 ocurre con una frecuencia de 1:4,000-1:6,000 nacidos vivos, mientras que la deleción 10p13p14 es detectada en 1:200,000 recién nacidos. Ambas deleciones comparten características clínicas similares tales como defectos cardiacos congénitos y anomalías inmunológicas. OBJETIVO: Identificar la deleción 22q11.2 en pacientes mexicanos con dismorfismo craneofacial sugestivo de síndrome DiGeorge o velocardiofacial y por lo menos con una característica clínica mayor (anomalía cardiaca, deficiencia inmunológica, defectos en paladar o retardo en el desarrollo). MÉTODOS: Estudio prospectivo de 39 pacientes captados entre 2012-2015 en el Instituto Mexicano del Seguro Social en Guadalajara, México. Los pacientes con características clínicas sugerentes de síndrome velocardiofacial o diagnostico confirmado de tetralogía de Fallot (TOF) o cardiopatía compleja fueron estudiados por bandas G y por hibridación in situ fluorescente (FISH) con una sonda dual TUPLE1(HIRA)/ARSA o TUPLE1(22q11)/22q13(SHANK3), seis pacientes sin la deleción 22q11.2 (seleccionados arbitrariamente) fueron estudiados con la sonda dual DiGeorge II (10p14)/D10Z1. RESULTADOS: Veintidós pacientes (7 hombres y 15 mujeres) tuvieron la deleción 22q11.2 y 17/39 no la tuvieron, ningún paciente tuvo la pérdida de 10p. Entre los 22 pacientes delecionados, 19 tuvieron defecto cardiaco congénito (principalmente TOF). Doce pacientes sin la deleción tuvieron defectos cardiacos congénitos como TOF (4/12), defecto del septo ventricular aislado (2/12) y otros trastornos cardiacos (6/12). CONCLUSIÓN: En nuestra pequeña muestra, alrededor de ~56% de los pacientes, independientemente de su diagnostico clínico, tuvieron la deleción 22q11.2 esperada. Resaltamos la importancia del diagnóstico citogenético temprano para determinar un apropiado manejo integral para el paciente y sus familiares.

22q11.2 deletion detected by in situ hybridization in Mexican patients with velocardiofacial syndrome-like features / Deleción 22q11.2 detectada por hibridación in situ en pacientes mexicanos con características clínicas similares al síndrome velocardiofacial

Abstract Introduction: Deletion 22q11.2 occurs in 1:4,000-1:6,000 live births while 10p13p14 deletion is found in 1:200,000 newborns. Both deletions have similar clinical features such as congenital heart disease and immunological anomalies. Objective: We looked for a 22q11.2 deletion in Mexican patients with craniofacial dysmorphisms suggestive of DiGeorge or velocardiofacial syndromes and at least one major phenotypic feature (cardiac anomaly, immune deficiency, palatal defects or development delay). Methods: A prospective study of 39 patients recruited in 2012-2015 at the Instituto Mexicano del Seguro Social at Guadalajara, Mexico. The patients with velocardiofacial syndrome-like features or a confirmed tetralogy of Fallot (TOF) or complex cardiopathy were studied by G-banding and fluorescence in situ hybridization (FISH) with a dual TUPLE1(HIRA)/ARSA or TUPLE1(22q11)/22q13(SHANK3) probe, six patients without the 22q11.2 deletion (arbitrarily selected) were tested with the dual DiGeorge II (10p14)/D10Z1 probe. Results: Twenty-two patients (7 males and 15 females) had the 22q11.2 deletion and 17/39 did not have it; no patient had a 10p loss. Among the 22 deleted patients, 19 had congenital heart disease (mostly TOF). Twelve patients without deletion had heart defects such as TOF (4/12), isolate ventricular septal defect (2/12) or other disorders (6/12). Conclusion: In our small sample about ~56% of the patients, regardless of the clinical diagnosis, had the expected 22q11.2 deletion. We remark the importance of early cytogenetic diagnosis in order to achieve a proper integral management of the patients and their families.

Resumen Introducción: La deleción 22q11.2 ocurre con una frecuencia de 1:4,000-1:6,000 nacidos vivos, mientras que la deleción 10p13p14 es detectada en 1:200,000 recién nacidos. Ambas deleciones comparten características clínicas similares tales como defectos cardiacos congénitos y anomalías inmunológicas. Objetivo: Identificar la deleción 22q11.2 en pacientes mexicanos con dismorfismo craneofacial sugestivo de síndrome DiGeorge o velocardiofacial y por lo menos con una característica clínica mayor (anomalía cardiaca, deficiencia inmunológica, defectos en paladar o retardo en el desarrollo) Métodos: Estudio prospectivo de 39 pacientes captados entre 2012-2015 en el Instituto Mexicano del Seguro Social en Guadalajara, México. Los pacientes con características clínicas sugerentes de síndrome velocardiofacial o diagnostico confirmado de tetralogía de Fallot (TOF) o cardiopatía compleja fueron estudiados por bandas G y por hibridación in situ fluorescente (FISH) con una sonda dual TUPLE1(HIRA)/ARSA o TUPLE1(22q11)/22q13(SHANK3), seis pacientes sin la deleción 22q11.2 (seleccionados arbitrariamente) fueron estudiados con la sonda dual DiGeorge II (10p14)/D10Z1. Resultados: Veintidós pacientes (7 hombres y 15 mujeres) tuvieron la deleción 22q11.2 y 17/39 no la tuvieron, ningún paciente tuvo la pérdida de 10p. Entre los 22 pacientes delecionados, 19 tuvieron defecto cardiaco congénito (principalmente TOF). Doce pacientes sin la deleción tuvieron defectos cardiacos congénitos como TOF (4/12), defecto del septo ventricular aislado (2/12) y otros trastornos cardiacos (6/12). Conclusión: En nuestra pequeña muestra, alrededor de ~56% de los pacientes, independientemente de su diagnostico clínico, tuvieron la deleción 22q11.2 esperada. Resaltamos la importancia del diagnóstico citogenético temprano para determinar un apropiado manejo integral para el paciente y sus familiares.

[Atypical deletions in Williams-Beuren syndrome]. / Deleciones atípicas en el síndrome Williams-Beuren.

The Williams-Beuren (SWB; OMIM 194050) syndrome is an autosomal dominant multisystem disorder that occurs in ~ 1 in 20,000 live births and results from a 7q11.23 deletion spanning ~ 28 genes. This deletion is caused by a nonallelic homologous recombination (NAHR) between low copy repeats present therein. The SWB phenotype is characterized by neonatal hypercalcemia, mental disability, distinctive personality and cognitive profile, short stature, dysmorphic facies, connective tissue disorders and supravalvular aortic stenosis. Ninety percent of the deletions are of 1.5 Mb, 8% of 1.84Mb, and only 2% are atypical. Although only ~ 40 atypical deletions have been described, they have contributed to clarify the genotype-phenotype correlation and allowed for a more integrative management. In this review we highlight the importance of detecting atypical deletions in patients with SWB.

El síndrome Williams-Beuren (SWB; OMIM 194050) es un trastorno multisistémico autosómico dominante que ocurre en ~ 1 de cada 20 000 nacidos vivos, y se debe a una deleción en 7q11.23 de ~ 28 genes. Esta deleción resulta de una recombinación homóloga no alélica entre repeticiones de bajo número de copias presentes en dicha región. El fenotipo SWB se caracteriza por hipercalcemia neonatal, discapacidad mental, personalidad y perfil cognitivo distintivos, baja estatura, facies dismórficas, trastornos del tejido conectivo y estenosis aórtica supravalvular. El 90% de las deleciones son de 1.5 Mb, 8% de 1.84 Mb, y solo el 2% son atípicas. Aunque solo se han descrito ~ 40 deleciones atípicas, estas han contribuido a esclarecer la correlación genotipo-fenotipo y permitido un manejo integral. En esta revisión se destaca la importancia de la detección de deleciones atípicas en pacientes con SWB.

Two familial intrachromosomal insertions with maternal dup(6)(p22.3p25.3) or dup(2)(q24.2q32.1) in recombinant offspring.

In this study, we describe two patients with a recombinant chromosome secondary to a maternal intrachromosomal insertion. Patient 1 was a girl with dup(6)(p22.3p25.3). Patient 2 was a boy with dup(2)(q24.2q32.1). Both familial rearrangements were characterized by means of GTG-bands, fluorescence in-situ hybridization, and comparative genomic hybridization microarray analyses. Patient 1 had an ∼23 Mb gain that involved the bands 6p22.3-6p25.3. Patient 2 had an ∼23 Mb gain (cytobands 2q24.2-2q32.1) and a further ∼1.9 Mb gain of 2p16.2-p16.3. The phenotype of each patient was in agreement with the typical 6p duplication or 2q24.2q32.1 duplication syndrome. The compound macular lesion in patient 1 suggests that retinal anomalies may be a part of the 6p trisomy phenotype. Among the 70 intrachromosomal insertions compiled here (including 68 from the literature), four were submicroscopic unbalanced insertions inherited from a balanced carrier and 66 were detectable on banded chromosomes (with or without array comparative genomic hybridization or other high-resolution assessment) and therefore spanned at least 5 Mb. Pericentric insertions are found in most chromosomes, whereas the paracentric ones are mainly observed in large and medium chromosome arms. That the former outnumber the latter in almost a 2 : 1 ratio appears to be related to the technique of diagnosis, size of the insertion, and size of the involved chromosome. Regardless of the apparent excess of carrier mothers, carriers of an intrachromosomal insertion beget almost twice as many children with a duplication than with a deletion.