Análise molecular de pacientes com síndromes de Smith-Magenis
Arquivos
Data
2011-03-03
Autores
Vieira, Gustavo Henrique [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A síndrome de Smith-Magenis (SMS) foi descrita , em 1986, como uma síndrome que envolvia uma mutação na região 17p em 9 pacientes. Sua prevalência esta estimada em um caso a cada 25.000 nascidos vivos. A SMS apresenta fenótipo que inclui características físicas, no desenvolvimento e comportamentais. Os sinais faciais se caracterizam por uma face larga e de forma quadrangular, braquicefalia, frontal proeminente, sinofre, fendas palpebrais alongadas para cima, ponte nasal larga, hipoplasia de face média, nariz largo e achatado, micrognatia na infância com relativa prognatia com a idade e lábio superior protruso e em „v‟ invertido. Os sinais clínicos mais importantes na SMS são comportamentais que levam a autoagressão, hiperatividade e déficit atenção. Foram estudados 31 pacientes brasileiros com suspeita diagnóstica de SMS. As análises genéticas realizadas para avaliar este grupo incluíram técnicas de citogenética molecular (FISH), aCGH, PCR quantitativa e busca por mutações na região de transcrição do gene RAI1. Os resultados demostraram que mais de 90% dos casos neste estudo tinham deficiência mental, atraso no desenvolvimento da fala e comportamento de auto-injúria. Além disso, 30% (9/30) tiveram deleção ou mutação de ponto na região 17p11.2 e RAI1 gene, sendo que 67% apresentaram uma deleção clássica (6/9), 11% tinham uma deleção atípica (1/9) e 22% (2/9) tinham uma mutação no gene RAI1. Foi possível determinar o ponto de quebra das deleções observadas e determinar os genes envolvidos. A deleção atípica descrita neste trabalho atingiu parte do gene RAI e até o momento não havia sido descrita. Além disso, duas mutações de ponto, no exon 3 do gene foram descritas. Por fim, dentro grupo estudado, foi diagnosticado um caso com síndrome da deleção 1p36, sendo possível a sugestão de um novo...
The Smith-Magenis syndrome (SMS) was described in 1986 as a syndrome involving a deletion in the 17p region in 9 patients. Its prevalence is estimated at one case per 25.000 live births. The SMS has phenotype that includes physical and behavioral development. The facial features are characterized by brachycephaly, midface hypoplasia, relative prognatism, everted, tented upper lip and deep-set, close-spaced eyes. The most important clinical features in SMS are leading behavioral self-injury, hyperactivity and attention deficit. We studied 31 Brazilian patients with suggested diagnostic to SMS. The genetic analysis performed to evaluate this group included molecular cytogenetic techniques (FISH), aCGH, quantitative PCR and the search for mutations in the gene transcription RAI1. Results showed that over 90% of the cases in this study had intellectual disability, delayed speech-language development, and self-injurious behavior. Furthermore, 30% had deletion or point mutation in the 17p11.2 region and RAI1 gene. Within this group, we found that 67% carried a classic deletion, 11% had an atypical deletion and 22% had a mutation in the RAI1 gene. It was possible to determine the breakpoint of the deletions observed and to determine the genes involved. The atypical deletion described reached part of the gene RAI1 and to date had not been described. In addition, two point mutations in exon 3 gene have been described. Finally, in this study group, one case was diagnosed with 1p36 deletion syndrome hinting of a possible new Differential Diagnosis for SMS. These findings add information for the etiology of SMS and may facilitate the development of new diagnostic tools, including FISH probes and sequencing-based screening for mutations.
The Smith-Magenis syndrome (SMS) was described in 1986 as a syndrome involving a deletion in the 17p region in 9 patients. Its prevalence is estimated at one case per 25.000 live births. The SMS has phenotype that includes physical and behavioral development. The facial features are characterized by brachycephaly, midface hypoplasia, relative prognatism, everted, tented upper lip and deep-set, close-spaced eyes. The most important clinical features in SMS are leading behavioral self-injury, hyperactivity and attention deficit. We studied 31 Brazilian patients with suggested diagnostic to SMS. The genetic analysis performed to evaluate this group included molecular cytogenetic techniques (FISH), aCGH, quantitative PCR and the search for mutations in the gene transcription RAI1. Results showed that over 90% of the cases in this study had intellectual disability, delayed speech-language development, and self-injurious behavior. Furthermore, 30% had deletion or point mutation in the 17p11.2 region and RAI1 gene. Within this group, we found that 67% carried a classic deletion, 11% had an atypical deletion and 22% had a mutation in the RAI1 gene. It was possible to determine the breakpoint of the deletions observed and to determine the genes involved. The atypical deletion described reached part of the gene RAI1 and to date had not been described. In addition, two point mutations in exon 3 gene have been described. Finally, in this study group, one case was diagnosed with 1p36 deletion syndrome hinting of a possible new Differential Diagnosis for SMS. These findings add information for the etiology of SMS and may facilitate the development of new diagnostic tools, including FISH probes and sequencing-based screening for mutations.
Descrição
Palavras-chave
Sindromes - Aspectos moleculares, Síndrome de Smith-Magenis, Microarranjo, Smith-Magenis syndrome, Microarray
Como citar
VIEIRA, Gustavo Henrique. Análise molecular de pacientes com síndromes de Smith-Magenis. 2011. 110 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2011.