Usefulness of the MS-MLPA technique in the diagnosis of Beckwith-Wiedemann syndrome and Silver-Russell syndrome.

INTRODUCTION: Epigenetic and genomic imprinting alterations of the 11p15.5 region cause excessive or deficient growth, which result in Beckwith-Wiedemann syndrome (BWS) or Silver-Russell syndrome (SRS), respectively. OBJECTIVE: To evaluate the methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) methylation analysis technique in the diagnosis of BWS and SRS. METHODS: 11p15.5 methylation and variants were evaluated in patients with clinical diagnosis of BWS and SRS using the MS-MLPA technique in peripheral blood DNA. RESULTS: Paternal uniparental disomy and loss of maternal IC2 methylation were identified in two patients with BWS who had omphalocele and macroglossia, respectively. Paternal IC1hypomethylation was recorded in two patients with SRS of classic phenotype. CONCLUSIONS: Adequate genotype-phenotype correlation was observed with the methylation defects that were identified, which confirms the usefulness of MLPA as a first-line study in patients diagnosed with BWS and SRS.

INTRODUCCIÓN: Las alteraciones epigenéticas y genómicas de la región improntada 11p15.5 producen crecimiento excesivo o deficiente, que se manifiesta como síndrome de Beckwith-Wiedemann o síndrome de Silver-Russell, respectivamente. OBJETIVO: Evaluar la técnica de análisis de metilación MLPA (MS-MLPA, methylation-specific multiplex ligation-dependent probe amplification) en el diagnóstico de los síndromes de Beckwith-Wiedemann y de Silver-Russell. MÉTODOS: Se evaluó la metilación y las variantes de 11p15.5 en pacientes con diagnóstico clínico de síndrome de Beckwith-Wiedemann y síndrome de Silver-Russell mediante la técnica MS-MLPA en ADN de sangre periférica. RESULTADOS: Se identificó disomía uniparental paterna y pérdida de metilación del IC2 materno en dos pacientes con síndrome de Beckwith-Wiedemann, quienes presentaron onfalocele y macroglosia, respectivamente. Se registró hipometilación paterna del IC1 en dos pacientes con síndrome de Silver-Russell de fenotipo clásico. CONCLUSIONES: Se observó adecuada correlación genotipo-fenotipo con los defectos de metilación encontrados, lo que confirma la utilidad del MLPA como estudio de primera línea en pacientes con diagnóstico de síndrome de Beckwith-Wiedemann y síndrome de Silver-Russell.

Silver-Russell syndrome: clinical, neurodevelopmental and communication characteristics: clinical case studies. / Síndrome de Silver-Russell: Características clínicas, de neurodesenvolvimento e comunicação: Estudo de casos clínicos.

Silver Russell Syndrome (SRS) is a genetically heterogeneous condition with a clinical phenotype that includes intrauterine and postnatal growth restriction, craniofacial alterations, body asymmetries, low body mass index, and feeding difficulties. Alterations in motor development, global coordination, and speech are expected. The current study aims to present the syndrome, neurodevelopment, and communication characteristics of three male children diagnosed with the syndrome, aged 16, 18, and 44 months, respectively. Ethical principles were followed. An analysis of the medical records, aiming to collect information of the anamnesis, conducted with the guardians, and of the assessment carried out with the children was performed. The assessment was performed by applying the following instruments: Communicative Behavior Observation (CBO), Development Screening Test Denver-II (TSDD-II), and the Early Language Milestone Scale (ELMS). The survey of characteristics confirmed the SRS hypothesis; it was verified a delay in communicative behavior for all participants in CBO; in TSDD-II there was a delay in gross motor, fine motor-adaptive, language, and social personal skills. Scores below expectations were found for receptive auditory and expressive auditory functions, with receptive abilities more developed than expressive abilities, in ELM. The SRS deserves to be recognized by the scientific community, since the phenotypic characteristics and the data from the previous life allow the hypothesis of the syndrome to be raised, aiming at an early correct diagnosis and therapeutic planning that minimizes the harmful effects of this condition.

A Síndrome de Silver Russel (SSR) é uma condição geneticamente heterogênea com fenótipo clínico que inclui restrição do crescimento intrauterino e pós-natal, alterações craniofaciais, assimetrias corporais, baixo índice de massa corporal e dificuldades alimentares. Há expectativa de alterações do desenvolvimento motor, da coordenação global e de fala. O presente estudo tem como objetivo apresentar características da síndrome, do neurodesenvolvimento e comunicação de três crianças do sexo masculino, com diagnóstico da síndrome, na faixa etária de 16, 18 e 44 meses, respectivamente. Cumpriram-se os critérios éticos. Foi realizada análise de prontuário, com objetivo de coletar informações da anamnese realizada com os responsáveis, e da avaliação realizada com as crianças. A avaliação foi realizada por meio da aplicação dos seguintes instrumentos: Observação do Comportamento Comunicativo (OCC), Teste de Screening de Desenvolvimento Denver-II (TSDD-II) e o Early Language Milestone Scale (ELMS). O levantamento de características confirmou a hipótese da SSR; na OCC verificou-se atraso nos comportamentos comunicativos para todos os participantes; no TSDD-II verificou-se atraso nas habilidades motora grossa, motora fina-adaptativa, linguagem e pessoal social. Na ELM verificou-se escores aquém do esperado para as funções auditiva receptiva e auditiva expressiva com habilidades receptivas mais desenvolvidas do que as habilidades expressivas. A SSR merece ser reconhecida pela comunidade científica, uma vez que as características fenotípicas e os dados de vida pregressa, possibilitam que seja levantada a hipótese da síndrome, visando o diagnóstico correto precocemente e um planejamento terapêutico que minimize os efeitos deletérios desta condição.

Síndrome de Silver-Russell. Aspectos clínicos y etiopatológicos de una entidad ejemplo de impronta genómica / Silver-Russell syndrome. Clinical and etiopathological aspects of a model genomic imprinting entity

El síndrome de Silver-Russell se caracteriza por retraso del crecimiento intrauterino asimétrico, con circunferencia craneal normal, barbilla pequeña y puntiaguda, que proporciona un aspecto de rostro triangular. Puede, además, presentar asimetría corporal, entre otros. Tiene una incidencia mundial estimada de 1 en 30 000-100 000 nacimientos, aunque este número es, probablemente, subestimado. En alrededor del 60 % de los casos, se puede identificar una causa molecular y la principal es la hipometilación del alelo paterno en la región de control de impresión 1 localizado en 11p15.5-p15.4. Realizar el diagnóstico de esta entidad, excluir los diagnósticos diferenciales y conocer las correlaciones (epi)genotipo-fenotipo son necesarios para realizar el adecuado seguimiento, brindar las opciones terapéuticas disponibles y el oportuno asesoramiento genético familiar. El objetivo del presente artículo es mostrar el estado actual del síndrome de Silver-Russell, un ejemplo de trastorno de impronta genómica.

Silver-Russell syndrome is characterized by asymmetrical intrauterine growth retardation, with normal head circumference and small, pointed chin, which results in a triangular face. It can also include body asymmetry, among other characteristics. Its global incidence is estimated at 1 in 30 000-100 000 births, even though this figure may be underestimated. In approximately 60 % of cases, a molecular cause can be identified, and the main one is hypomethylation of the paternal allele at the imprinting control region 1 located at 11p15.5-p15.4. It is necessary to make the diagnosis of this entity, exclude differential diagnoses, and know (epi)genotype-phenotype correlations in order to ensure an adequate follow-up, provide available therapeutic options, and offer a timely family genetic counseling. The objective of this article is to describe the current status of the Silver-Russell syndrome, a model of genomic imprinting disorder.

Silver-Russell syndrome. Clinical and etiopathological aspects of a model genomic imprinting entity. / Síndrome de Silver-Russell. Aspectos clínicos y etiopatológicos de una entidad ejemplo de impronta genómica.

Silver-Russell syndrome is characterized by asymmetrical intrauterine growth retardation, with normal head circumference and small, pointed chin, which results in a triangular face. It can also include body asymmetry, among other characteristics. Its global incidence is estimated at 1 in 30 000-100 000 births, even though this figure may be underestimated. In approximately 60 % of cases, a molecular cause can be identified, and the main one is hypomethylation of the paternal allele at the imprinting control region 1 located at 11p15.5-p15.4. It is necessary to make the diagnosis of this entity, exclude differential diagnoses, and know (epi)genotype-phenotype correlations in order to ensure an adequate follow-up, provide available therapeutic options, and offer a timely family genetic counseling. The objective of this article is to describe the current status of the Silver-Russell syndrome, a model of genomic imprinting disorder.

El síndrome de Silver-Russell se caracteriza por retraso del crecimiento intrauterino asimétrico, con circunferencia craneal normal, barbilla pequeña y puntiaguda, que proporciona un aspecto de rostro triangular. Puede, además, presentar asimetría corporal, entre otros. Tiene una incidencia mundial estimada de 1 en 30 000- 100 000 nacimientos, aunque este número es, probablemente, subestimado. En alrededor del 60 % de los casos, se puede identificar una causa molecular y la principal es la hipometilación del alelo paterno en la región de control de impresión 1 localizado en 11p15.5-p15.4. Realizar el diagnóstico de esta entidad, excluir los diagnósticos diferenciales y conocer las correlaciones (epi)genotipo-fenotipo son necesarios para realizar el adecuado seguimiento, brindar las opciones terapéuticas disponibles y el oportuno asesoramiento genético familiar. El objetivo del presente artículo es mostrar el estado actual del síndrome de Silver-Russell, un ejemplo de trastorno de impronta genómica.

Síndrome Rusell Silver. Presentación de caso / Russell-Silver syndrome. Presentation of a case

RESUMEN El síndrome Russell Silver es una enfermedad genética de baja frecuencia, caracterizada por retardo del crecimiento prenatal y postnatal, dismorfias faciales y digitales, así como asimetría corporal. Se presenta una paciente femenina de dos años de edad, remitida a consulta de Genética Clínica, por retardo en el desarrollo pondoestatural psicomotor, dismorfias faciales y asimetría corporal. Se realizño el diagnóstico clínico de esta afección. Es importante establecer un diagnóstico precoz para la estimulación temprana, seguimiento multidisciplinario y se brindó un adecuado asesoramiento genético a los familiares (AU).

ABSTRACT The Russell-Silver syndrome is a low-frequency genetic disease, characterized by a pre-natal growth retardation and postnatal digital and facial dysmorphia, and also body asymmetry. We present a female patient, aged 2 years, who was remitted to the consultation of Clinical Genetics because of a retardation in the psychomotor, height-weight development, facial dysmorphia and body asymmetry. The disease was clinically diagnosed. It is important to arrive to a precocious diagnosis for the early stimulation, multidisciplinary follow-up and adequate genetic advice to the relatives (AU).

Targeted Next Generation Sequencing Approach in Patients Referred for Silver-Russell Syndrome Testing Increases the Mutation Detection Rate and Provides Decisive Information for Clinical Management.

OBJECTIVE: To investigate the contribution of differential diagnoses to the mutation spectrum of patients referred for Silver-Russell syndrome (SRS) testing. STUDY DESIGN: Forty-seven patients referred for molecular testing for SRS were examined after exclusion of one of the SRS-associated alterations. After clinical classification, a targeted next generation sequencing approach comprising 25 genes associated with other diagnoses or postulated as SRS candidate genes was performed. RESULTS: By applying the Netchine-Harbinson clinical scoring system, indication for molecular testing for SRS was confirmed in 15 out of 47 patients. In 4 out of these 15 patients, disease-causing variants were found in genes associated with other diagnoses. These patients carried mutations associated with Bloom syndrome, Mulibrey nanism, KBG syndrome, or IGF1R-associated short stature. We could not detect any pathogenic mutation in patients with a negative clinical score. CONCLUSIONS: Some of the differential diagnoses detected in the cohort presented here have a major impact on clinical management. Therefore, we emphasize that the molecular defects associated with these clinical pictures should be excluded before the clinical diagnosis "SRS" is made. Finally, we could show that a broad molecular approach including the differential diagnoses of SRS increases the detection rate.

[Silver-Russell syndrome (hemihypertrophy) and cor triatriatum in a newborn]. / Símdrome de Silver-Russell (hemihipertrofia) y cor triatriatum en un neonato.

Hemihypertrophy syndrome and cor triatriatum are extremely rare pathologies. Hemihypertrophy is defined as complete or partial overgrowth of one of the hemibodies. Cor triatriatum is a congenital heart disease characterized by a membrane which separates the left atrium into two chambers; if that membrane has a restrictive hole, it causes obstruction to blood passage from the pulmonary veins into the left ventricle causing hypertension and pulmonary edema. In this context, the patent ductus arteriosus can act as a means of decompression of the pulmonary circuit, because it allows the blood passage from the pulmonary artery to the aorta. We report a patient with Silver-Rusell syndrome (hemihypertrophy), cor triatriatum and ductus arteriosus with reverse flow. To our knowledge, this association of rare pathologies and this clinical presentation have not been described previously.

Co-existence of 9p deletion and Silver-Russell syndromes in a patient with maternally inherited cryptic complex chromosome rearrangement involving chromosomes 4, 9, and 11.

We report a patient with a maternally inherited unbalanced complex chromosomal rearrangement (CCR) involving chromosomes 4, 9, and 11 detected by microarray comparative genomic hybridization (aCGH) and fluorescence in situ hybridization (FISH). This patient presents with clinical features of 9p deletion syndrome and Silver-Russell syndrome (SRS). Chromosome analysis performed in 2000 showed what appeared to be a simple terminal deletion of chromosome 9p22.1. aCGH performed in 2010 revealed a 1.63 Mb duplication at 4q28.3, a 15.48 Mb deletion at 9p24.3p22.3, and a 1.95 Mb duplication at 11p15.5. FISH analysis revealed a derivative chromosome 9 resulting from an unbalanced translocation between chromosomes 9 and 11, a chromosome 4 fragment inserted near the breakpoint of the translocation. The 4q28.3 duplication does not contain any currently known genes. The 9p24.3p22.3 deletion region contains 36 OMIM genes including a 3.5 Mb critical region for the 9p-phenotype. The 11p15.5 duplication contains 49 OMIM genes including H19 and IGF2. Maternal aCGH was normal. However, maternal chromosomal and FISH analyses revealed an apparently balanced CCR involving chromosomes 4, 9, and 11. To the best of our knowledge, this is the first report of a patient with maternally inherited trans-duplication of the entire imprinting control region 1 (ICR1) among the 11p15.5 duplications reported in SRS patients. This report supports the hypothesis that the trans-duplication of the maternal copy of ICR1 alone is sufficient for the clinical manifestation of SRS and demonstrates the usefulness of combining aCGH with karyotyping and FISH for detecting cryptic genomic imbalances.

Molecular karyotyping as a relevant diagnostic tool in children with growth retardation with Silver-Russell features.

OBJECTIVE: To determine the contribution of submicroscopic chromosomal imbalances to the etiology of Silver-Russell syndrome (SRS) and SRS-like phenotypes. STUDY DESIGN: We performed molecular karyotyping in 41 patients with SRS or SRS-like features without known chromosome 7 and 11 defects using the Affymetrix SNP Array 6.0 system (Affymetrix, High Wycombe, United Kingdom). RESULTS: In 8 patients, pathogenic copy number variations with sizes ranging from 672 kb to 9.158 Mb were identified. The deletions in 1q21, 15q26, 17p13, and 22q11 were associated with known microdeletion syndromes with overlapping features with SRS. The duplications in 22q13 and Xq25q27 represent unique novel copy number variations but have an obvious influence on the phenotype. In 5 additional patients, the pathogenetic relevance of the detected variants remained unclear. CONCLUSION: Pathogenic submicroscopic imbalances were detectable in a significant proportion of patients with short stature and features reminiscent of SRS. Therefore, molecular karyotyping should be implemented in routine diagnostics for growth-retarded patients with even slight dysmorphisms suggestive for SRS.

Post-receptor IGF1 insensitivity restricted to the MAPK pathway in a Silver-Russell syndrome patient with hypomethylation at the imprinting control region on chromosome 11.

BACKGROUND: Hypomethylation of the paternal imprinting center region 1 (ICR1) is the most frequent molecular cause of Silver-Russell syndrome (SRS). Clinical evidence suggests that patients with this epimutation have mild IGF1 insensitivity. OBJECTIVE: To assess in vitro IGF1 action in fibroblast culture from a patient with SRS and IGF1 insensitivity. METHODS: Fibroblast cultures from one patient with SRS due to ICR1 demethylation and controls were established. The SRS patient has severe growth failure, elevated IGF1 level, and poor growth rate during human recombinant GH treatment. IGF1 action was assessed by cell proliferation, AKT, and p42/44-MAPK phosphorylation. Gene expression was determined by real-time PCR. RESULTS: Despite normal IGF1R sequence and expression, fibroblast proliferation induced by IGF1 was 50% lower in SRS fibroblasts in comparison with controls. IGF1 and insulin promoted a p42/44-MAPK activation in SRS fibroblasts 40 and 36%, respectively, lower than that in control fibroblasts. On the other hand, p42/44-MAPK activation induced by EGF stimulation was only slightly reduced (75% in SRS fibroblasts in comparison with control), suggesting a general impairment in MAPK pathway with a greater impairment of the stimulation induced by insulin and IGF1 than by EGF. A PCR array analysis disclosed a defect in MAPK pathway characterized by an increase in DUSP4 and MEF2C gene expressions in patient fibroblasts. CONCLUSION: A post-receptor IGF1 insensitivity was characterized in one patient with SRS and ICR1 hypomethylation. Although based on one unique severely affected patient, these results raise an intriguing mechanism to explain the postnatal growth impairment observed in SRS patients that needs confirmation in larger cohorts.

Microduplication of the ICR2 domain at chromosome 11p15 and familial Silver-Russell syndrome.

Silver-Russell syndrome (SRS) is characterized by severe intrauterine and postnatal growth retardation in association with a typical small triangular face and other variable features. Genetic and epigenetic disturbances are detected in about 50% of the patients. Most frequently, SRS is caused by altered gene expression on chromosome 11p15 due to hypomethylation of the telomeric imprinting center (ICR1) that is present in at least 40% of the patients. Maternally inherited duplications encompassing ICR1 and ICR2 domains at 11p15 were found in a few patients, and a microduplication restricted to ICR2 was described in a single SRS child. We report on a microduplication of the ICR2 domain encompassing the KCNQ1, KCNQ1OT1, and CDKN1C genes in a three-generation family: there were four instances of paternal transmissions of the microduplication from a single male uniformly resulting in normal offspring, and five maternal transmissions, via two clinically normal sisters, with all the children exhibiting SRS. This report provides confirmatory evidence that a microduplication restricted to the ICR2 domain results in SRS when maternally transmitted.