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BACKGROUND: Diagnosing imprinting defects in neonates and young children presents challenges, often necessitating molecular analysis for a conclusive diagnosis. The isolation of genetic material from oral swabs becomes crucial, especially in settings where blood sample collection is impractical or for vulnerable populations like newborns, who possess limited blood volumes and are often too fragile for invasive procedures. Oral swab samples emerge as an excellent source of DNA, effectively overcoming obstacles associated with rare diseases. METHODS: In our study, we specifically addressed the determination of the quality and quantity of DNA extracted from oral swab samples using NaCl procedures. RESULTS: We compared these results with extractions performed using a commercial kit. Subsequently, the obtained material underwent MS-HRM analysis for loci associated with imprinting diseases such as Prader-Willi and Angelman syndromes. CONCLUSIONS: Our study emphasizes the significance of oral swab samples as a reliable source for obtaining DNA for MS-HRM analysis. NaCl extraction stands out as a practical and cost-effective method for genetic studies, contributing to a molecular diagnosis that proves particularly beneficial for patients facing delays in characterization, ultimately influencing their treatment.

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In this editorial the author presents a study, concerning Prader-Willi syndrome, which is paradigmatic for translational medicine, given that it creates a synergy between genetics and molecular biology, in order to improve the care for patients suffering from this syndrome.

En el presente editorial el autor expone un estudio, relacionado con el síndrome de Prader-Willi, que es paradigmático para la medicina traslacional, dado que crea una sinergia entre la genética y la biología molecular, a fin de mejorar la atención a los pacientes que padecen este síndrome.

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BACKGROUND: Prader Willi syndrome (PWS) and Angelman syndrome (AS) are neurodevelopmental disorders caused by deletions or methylation defects, making a loss of expression of imprinted genes located in the 15q11-q13 region, and these can be assessed by different cytogenomic and molecular techniques. We report a case series of patients with PWS and AS evaluated through the MS-MLPA assay. CLINICAL CASES: We studied four patients with a clinical diagnosis of PWS and another with AS, evaluated as far as possible with karyotype and FISH, and with MS-MLPA assay for the 15q11-q13 region in all cases. In patients with PWS, neonatal hypotonia was the main reason for consultation and in three of them we identified a deletion of 15q11-q13 by MS-MLPA, also confirmed by FISH; and in the other one, an abnormal methylation pattern consistent with a maternal uniparental disomy. The patient with AS presented with a typical picture which led to the identification of a deletion in 15q11-q13 by MS-MLPA, also confirmed by FISH. CONCLUSIONS: The use of the MS-MLPA assay for the 15q11-q13 region was very useful for the diagnosis and identification of the genomic and epigenetic defects involved in either PWS and AS.

INTRODUCCIÓN: el síndrome Prader-Willi (SPW) y el síndrome de Angelman (SA) son trastornos del neurodesarrollo producidos por deleciones o defectos de metilación que producen pérdida de expresión en los genes improntados de la región 15q11 q13, mismos que pueden ser evaluados por diferentes técnicas citogenómicas y moleculares. Presentamos una serie de pacientes con SPW y SA en los que se identificó el tipo de defecto de la región 15q11-q13 mediante la técnica de MS-MLPA. CASOS CLÍNICOS: estudiamos cuatro pacientes con diagnóstico clínico de SPW y uno con SA, evaluados en lo posible con cariotipo, FISH y todos con ensayo MS-MLPA para la región 15q11-q13. En los pacientes con SPW, la hipotonía neonatal fue el motivo principal de consulta. En tres de ellos se identificó deleción de 15q11-q13 por MS-MLPA, confirmada por FISH, y en uno el patrón de metilación anormal fue compatible con una disomía uniparental materna. El paciente con SA presentó un cuadró típico y también se identificó una deleción en 15q11-q13 por MS-MLPA, confirmada por FISH. CONCLUSIONES: confirmamos que el uso de la técnica de MS-MLPA para la región 15q11 q13 mostró ser de gran utilidad para identificar los mecanismos genómicos y epigenéticos implicados en el SPW y el SA.

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Prader-Willi (PWS) and Angelman (AS) syndromes are two clinically distinct imprinted disorders characterized by genetic abnormalities at 15q11-q13. Early diagnosis of both syndromes provides improved treatment and accurate genetic counseling. Whole blood (WB) is the most common DNA source of many methodologies to detect PWS and AS, however, the need of WB makes a massive screening difficult in newborns due to economic and technical limitations. The aim of this study was to adapt a Methylation-sensitive High-Resolution Melting (MS-HRM) approach from dried blood spot (DBS) samples, assessing the different DNA isolation techniques and diagnostic performance. Over a 1-year period, we collected 125 DBS cards, of which 45 had already been diagnosed by MS-HRM (20 PWS, 1 AS, and 24 healthy individuals). We tested three different DBS-DNA extraction techniques assessing the DNA concentration and quality, followed by MS-HRM and statistical comparison. Each DBS-DNA extraction method was capable of accuracy in detecting all PWS and AS individuals. However, the efficiency to detect healthy individuals varied according to methodology. In our experience, DNA extracted from DBS analyzed by the MS-HRM methodology provides an accurate approach for genetic screening of imprinting related disorders in newborns, offering several benefits compared to traditional whole blood methods.

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PURPOSE: This study aimed to present findings on language, behavior, and neurodevelopment in a girl diagnosed with Angelman Syndrome, evaluated when she was three and eight years old. METHODS: The following evaluation instruments were used: Observation of Communication Behavior, Early Language Milestone (ELM) Scale, and Denver Developmental Screening Test, 2nd edition (DDST-II). RESULTS: In this case report, presence of AS phenotype signals such as wide mouth and wide-spaced teeth, tongue thrusting, strabismus, up slanting palpebral fissures, and sialorrhea are verified. Expressive and receptive deficits were verified in the language assessment, with the absence of orality and loss of comprehension with very similar performances in both evaluations. The ELM and DDST-II tests indicated severe impairment of all abilities evaluated at both three and eight years of age. Performance was quite similar in both evaluations in all areas of child development. Little progress was observed over time despite the great therapeutic and educational investment. CONCLUSION: The presence of a complex scenario such as AS demands high complexity clinical needs, a situation that is worsened due to scarcity of therapeutic resources that could minimize the harmful impacts of AS and culminate in increased quality of life for the AS population and their families.

OBJETIVO: O objetivo deste estudo é apresentar achados de linguagem, comportamento e neurodesenvolvimento de uma menina com diagnóstico da Síndrome de Angelman, avaliada aos três e aos oito anos. MÉTODO: Os instrumentos de avaliação foram Observação do Comportamento Comunicativo, Early Language Milestone Scale (ELM) e Teste de Screening de Desenvolvimento DENVER-II (TSDD-II). RESULTADOS: No caso apresentado, verifica-se a presença dos sinais fenotípicos da SA, tais como boca larga, dentes espaçados, língua protuberante, estrabismo, fissuras palpebrais ascendentes e sialorreia. Na avaliação de linguagem, foram verificados déficits expressivos e receptivos, com ausência de oralidade e prejuízos na compreensão. O TSDD-II e a ELMS indicaram grave comprometimento de todas as habilidades avaliadas aos três e aos oito anos. O desempenho encontrado, nas duas avaliações, foi muito semelhante em todas as áreas do desenvolvimento infantil. Ao longo dos anos, verificou-se pouca evolução, apesar do grande investimento terapêutico e educacional. CONCLUSÃO: A presença de um quadro complexo como a SA demanda necessidades clínicas de alta complexidade, situação agravada frente à escassez de recursos terapêuticos que possam minimizar os impactos deletérios da síndrome, culminando em comprometimento da qualidade de vida da população com a SA, bem como de suas famílias.

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BACKGROUND: Prader Willi (PWS) and Angelman (AS) syndromes are rare genetic disorders characterized by deletions, uniparental disomy, and imprinting defects at chromosome 15. The loss of function of specific genes caused by genetic alterations in paternal allele causes PWS while the absence in maternal allele results AS. The laboratory diagnosis of PWS and AS is complex and demands molecular biology and cytogenetics techniques to identify the genetic mechanism related to the development of the disease. The DNA methylation analysis in chromosome 15 at the SNURF-SNRPN locus through MS-PCR confirms the diagnosis and distinguishes between PWS and AS. Our study aimed to establish the MS-PCR technique associated with High-Resolution Melting (MS-HRM) in PWS and AS diagnostic with a single pair of primers. METHODS: We collected blood samples from 43 suspected patients to a cytogenetic and methylation analysis. The extracted DNA was treated with bisulfite to perform comparative methylation analysis. RESULTS: MS-HRM and MS-PCR agreed in 100% of cases, identifying 19(44%) PWS, 3(7%) AS, and 21(49%) Normal. FISH analysis detected four cases of PWS caused by deletions in chromosome 15. CONCLUSION: The MS-HRM showed good performance with a unique pair of primers, dispensing electrophoresis gel analysis, offering a quick and reproducible diagnostic.

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RESUMO Objetivo O objetivo deste estudo é apresentar achados de linguagem, comportamento e neurodesenvolvimento de uma menina com diagnóstico da Síndrome de Angelman, avaliada aos três e aos oito anos. Método Os instrumentos de avaliação foram Observação do Comportamento Comunicativo, Early Language Milestone Scale (ELM) e Teste de Screening de Desenvolvimento DENVER-II (TSDD-II). Resultados No caso apresentado, verifica-se a presença dos sinais fenotípicos da SA, tais como boca larga, dentes espaçados, língua protuberante, estrabismo, fissuras palpebrais ascendentes e sialorreia. Na avaliação de linguagem, foram verificados déficits expressivos e receptivos, com ausência de oralidade e prejuízos na compreensão. O TSDD-II e a ELMS indicaram grave comprometimento de todas as habilidades avaliadas aos três e aos oito anos. O desempenho encontrado, nas duas avaliações, foi muito semelhante em todas as áreas do desenvolvimento infantil. Ao longo dos anos, verificou-se pouca evolução, apesar do grande investimento terapêutico e educacional. Conclusão A presença de um quadro complexo como a SA demanda necessidades clínicas de alta complexidade, situação agravada frente à escassez de recursos terapêuticos que possam minimizar os impactos deletérios da síndrome, culminando em comprometimento da qualidade de vida da população com a SA, bem como de suas famílias.

ABSTRACT Purpose This study aimed to present findings on language, behavior, and neurodevelopment in a girl diagnosed with Angelman Syndrome, evaluated when she was three and eight years old. Methods The following evaluation instruments were used: Observation of Communication Behavior, Early Language Milestone (ELM) Scale, and Denver Developmental Screening Test, 2nd edition (DDST-II). Results In this case report, presence of AS phenotype signals such as wide mouth and wide-spaced teeth, tongue thrusting, strabismus, up slanting palpebral fissures, and sialorrhea are verified. Expressive and receptive deficits were verified in the language assessment, with the absence of orality and loss of comprehension with very similar performances in both evaluations. The ELM and DDST-II tests indicated severe impairment of all abilities evaluated at both three and eight years of age. Performance was quite similar in both evaluations in all areas of child development. Little progress was observed over time despite the great therapeutic and educational investment. Conclusion The presence of a complex scenario such as AS demands high complexity clinical needs, a situation that is worsened due to scarcity of therapeutic resources that could minimize the harmful impacts of AS and culminate in increased quality of life for the AS population and their families.

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La región q11-q13 del cromosoma 15 humano es proclive a sufrir alteraciones genéticas. Algunos genes de la región presentan expresión parental diferencial monoalélica, regulada por imprinting (EI). Errores en la regulación del EI, disomías uniparentales (DSU), así como también el cambio en el número de copias genómicas (CNV) producidos por sitios susceptibles de quiebre cromosómico (BP), producen alteraciones en esta región. Las enfermedades más frecuentes asociadas son el síndrome de Prader-Willi, el síndrome de Angelman y el síndrome de microduplicación 15q11-q13. En el presente trabajo analizamos la región 15q11-q13 por Methyl specific-multiplex ligation-dependent probe amplification (MS-MLPA) en 181 muestras de ADN derivadas a nuestro servicio de análisis genético molecular. En este trabajo mostramos que, de las 181 muestras, 39 presentaron alteraciones detectables por MS-MLPA. El 61.5% (24/39) de esas alteraciones detectadas fueron deleciones, el 5.1% (2/39) duplicaciones y el 33.3%(13/39) DSU/EI. Los CNV fueron 4 veces más frecuentes que las DSU/EI (OR = 4; IC 95%: 1.56-10.25) consistente con la literatura. Entre los CNV, dos casos atípicos permiten postular posibles sitios BP que no han sido informados en la literatura previamente.

Human chromosome 15q11-q13 region is prone to suffer genetic alterations. Some genes of this region have a differential monoallelic imprinting-regulated expression pattern. Defects in imprinting regulation (IE), uniparental disomy (UPD) or copy number variation (CNV) due to chromosomal breakpoints (BP) in 15q11-q13 region, are associated with several diseases. The most frequent are Prader-Willi syndrome, Angelman syndrome and 15q11-q13 microduplication syndrome. In this work, we analyzed DNA samples from 181 patients with phenotypes which were compatible with the above-mentioned diseases, using Methyl specific-multiplex ligation-dependent probe amplification (MS-MLPA). We show that, of the 181 samples, 39 presented alterations detectable by MS-MLPA. Of those alterations, 61.5% (24/39) were deletions, 5.1% (2/39) duplications and 33.3% (13/39) UPD/IE. The CNV cases were 4 times more frequent than UPD/IE (OR= 4; IC 95%: 1.56-10.25), consistent with the literature. Among the CNVs, two atypical cases allow to postulate new possible BP sites that have not been reported previously in the literature.

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Human chromosome 15q11-q13 region is prone to suffer genetic alterations. Some genes of this region have a differential monoallelic imprinting-regulated expression pattern. Defects in imprinting regulation (IE), uniparental disomy (UPD) or copy number variation (CNV) due to chromosomal breakpoints (BP) in 15q11-q13 region, are associated with several diseases. The most frequent are Prader-Willi syndrome, Angelman syndrome and 15q11-q13 microduplication syndrome. In this work, we analyzed DNA samples from 181 patients with phenotypes which were compatible with the above-mentioned diseases, using Methyl specific-multiplex ligation-dependent probe amplification (MS-MLPA). We show that, of the 181 samples, 39 presented alterations detectable by MS-MLPA. Of those alterations, 61.5% (24/39) were deletions, 5.1% (2/39) duplications and 33.3% (13/39) UPD/IE. The CNV cases were 4 times more frequent than UPD/IE (OR= 4; IC 95%: 1.56-10.25), consistent with the literature. Among the CNVs, two atypical cases allow to postulate new possible BP sites that have not been reported previously in the literature.

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El síndrome de Angelman es un trastorno neurogenético debido a la falta o reducción en la expresión del gen UBE3A en el cromosoma 15, el cual codifica la proteína ubiquitina ligasa E3A, que tiene un papel integral en el desarrollo sinóptico y la plasticidad neuronal. Se manifiesta por retraso en el neurodesarrollo o discapacidad intelectual, comportamiento característico y epilepsia. Se describen las características clínicas de siete pacientes con deleción del cromosoma 15q11-13 y su manejo integral. Por la expectativa de vida, es importante conocer y manejar las comorbilidades de forma interdisciplinaria para lograr mejorar la calidad de vida de los afectados. Se realiza una revisión de la literatura sobre la aproximación integral al diagnóstico y cuidado clínico a largo plazo de los pacientes con síndrome de Angelman.

Angelman syndrome is a neurogenetic disorder caused by a lack or reduction of expression of UBE3A located within chromosome 15, which codes for ubiquitin protein ligase E3A, which has a key role in synaptic development and neural plasticity. Its main features are developmental delay/intellectual disability, lack of speech, a characteristic behavioural profile, and epilepsy. We describe clinical features and management of seven cases with 15q11-13 deletion. Due to their life expectancy, knowing and managing its comorbidities is crucial to improve their quality of life. We review the diagnosis and long-term clinical care of patients with Angelman syndrome.

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