RESUMEN

Resumen La amplificación de sondas múltiples dependientes de ligación (MLPA) es una valiosa herramienta en el estudio de alteraciones en el número de copias para distintas patologías de origen genético. La existencia de una amplia oferta de kits comerciales, el fácil y rápido procesamiento de laboratorio, su alta sensibilidad y, en general, los buenos resultados informados han permitido que su uso se encuentre expandido en muchos laboratorios de biología molecular alrededor del mundo. El principio de esta técnica ha sido adaptado para distintas aplicaciones como la MLPA metilación específica para el estudio de enfermedades relacionadas con la impronta epigenética y la MLPA digital que se acopla a equipos de secuenciación de nueva generación para aumentar la cantidad de regiones analizadas en un solo ensayo. Al contar con 10 años de experiencia en el uso de esta técnica en el Laboratorio Nacional de Tamizaje Neonatal y Alto Riesgo se realiza esta revisión con el fin de analizar los principios, variantes de la técnica, análisis de los datos, algunas aplicaciones, ventajas y desventajas de la MLPA en comparación con otras tecnologías disponibles.

Abstract Multiplex ligation-dependent probe amplification (MLPA) is a valuable tool in the study of copy number alterations for different pathologies of genetic origin. The availability of a wide range of commercial kits, the easy and fast laboratory processing, its high sensitivity and, in general, the good results reported have allowed its use to be expanded in many molecular biology laboratories around the world. The basic principle of this technique has been adapted for different applications such as specific methylation MLPA for the study of diseases related to epigenetic imprinting and digital MLPA that is coupled to next-generation sequencing equipment to increase the number of regions analysed in a single trial. With 10 years of experience in the use of this technique, the National Laboratory for Neonatal and High Risk Screening performs this review in order to analyse the principles, variants of the technique, data analysis, some applications, and advantages and disadvantages of MLPA compared to other available technologies.

Resumo A amplificação de múltiplas sondas dependentes de ligação (MLPA) é uma ferramenta valiosa no estudo das alterações do número de cópias para diferentes patologias de origem genética. A existência de uma ampla gama de kits comerciais, processamento laboratorial fácil e rápido, alta sensibilidade e, em geral, os bons resultados relatados, permitiram que seu uso se encontre expandido em muitos laboratórios de biologia molecular ao redor do mundo. O princípio desta técnica foi adaptado para diferentes aplicações como a MLPA metilação específica para o estudo de doenças relacionadas com o imprinting epigenético e a MLPA digital que é acoplada a equipamentos de sequenciamento de nova geração para aumentar o número de regiões analisadas em um único ensaio. Com 10 anos de experiência no uso da técnica, o Laboratório Nacional de Triagem Neonatal e de Alto Risco realiza esta revisão visando a analisar os princípios, variantes da técnica, análise dos dados, algumas aplicações, vantagens e desvantagens da MLPA comparado com outras tecnologias disponíveis.

RESUMEN

Steroid 21-hydroxylase deficiency accounts for 95% of congenital adrenal hyperplasia (CAH) cases. Newborn screening has allowed for early detection of the disease, and currently, molecular analysis can identify the genotypes of these patients. Phenotype-genotype correlation has been well described in previous studies. In Costa Rica, there is no data about the genetic background of these patients, nor their phenotypic correlation. DESIGN: Observational, retrospective, descriptive study based on the review of patient records who had a diagnosis of CAH and were performed molecular analysis using gene sequencing or MLPA during the period from 2006 to 2018 (N = 58). OBJECTIVE: To describe the clinical and genetic characteristics of CAH patients due to 21-hydroxylase deficiency at the National Children's Hospital "Dr. Carlos Sáenz Herrera", Caja Costarricense de Seguro Social (CCSS) in Costa Rica. RESULTS: 53% (31/58) of the patients were male and 80% (37/46) were born full term; 72% (42/58) had salt wasting phenotype, 9% (5/58) simple virilizing phenotype and 19% (11/58) non-classic phenotype. The most frequent variants were c.292+5G>A in 26% (15/58) of patients and Del/Del in 21% (12/58) of them. CONCLUSIONS: The most frequent mutation in our study population was the c.292+5G>A, which was found in 15/58 patients. This rare variant has only been reported in three other studies so far but as an infrequent mutation in CAH patients. The genetic characteristics of Costa Rican patients differ from what has been documented worldwide and could respond to a founder effect.