Utilidad de la técnica de MS-MLPA en el diagnóstico de los síndromes de Beckwith-Wiedemann y Silver-Russell / Usefulness of the MS-MLPA technique in the diagnosis of Beckwith-Wiedemann syndrome and Silver-Russell syndrome

Resumen 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.

Abstract 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.

Genetic analysis of an adult with mosaicism of uniparental disomy 11p / 中华医学遗传学杂志

Objective@#To analyze the clinical phenotype and genomic abnormality of an adult featuring congenital heart defect and multiple developmental disorders.@*Methods@#The patient was subjected to conventional G-banding chromosomal karyotyping and single nucleotide polymorphism microarray (SNP-array) analysis.@*Results@#The patient showed a normal karyotype, while SNP-array revealed a 42.7 Mb mosaic uniparental disomy (UPD) in the 11p15.5p12 region ([hg19] chr11: 491 333 - 43 189 376).@*Conclusion@#The mosaicism of UPD of 11p15.5p12 region probably underlies the congenital heart defect and developmental disorders in the patient.

Analysis of genetic defects in the 11p15.5 region in Russell-Silver syndrome / 临床儿科杂志

Objective To explore the pathogenesis of Russell-Silver syndrome (RSS). Methods Two milliliter peripheral blood samples were collected from 6 male patients aged 6 to 8 years with suspected RSS phenotype, the parents of 2 patients and 5 healthy boys. Mononuclear cells were isolated and genomic DNA was extracted. The methylation level of the H19 imprinting control region(ICR)1 on chromosome 11p15.5 was detected by pyrosequencing.The methylation status and the copy number variation in the corresponding region of one RSS patient with positive results by pyrosequencing were analysed by methylation-specific multiplex-ligation-dependent probe amplification assay (MS-MLPA). Results Pyrosequencing analysis revealed that the methylation rates on the 6 CpG targeting sites in H19 differentially methylated region(DMR)in the 6 RSS patients were about 11%~29%, which were significantly lower than those in their parents and normal controls (44%~59%). The MS-MLPA results of one patient with positive pyrosequencing showed that the methylation rates of 4 sites in H19-DMR were about 10%,which was obviously lower than the normal level.The methylation rates of the 4 sites in KCNQ1OT1 gene were about 50%, which was in the normal range. The copy number variations from all samples detected were in the normal range. Conclusion There is methylation aberration of H19-DMR in ICR1 in children with RSS.