Aumento na taxa de diagnóstico genético dos pacientes a partir da identificação de CNVs, por CMA, envolvendo genes implicados com a manifestação clínica da deficiência intelectual

• Autor(a) principal: Pinto, Irene Plaza
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/00130000094n4
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/9695
• topic: Análise cromossômica por microarranjo; CNTNAP2; SHANK3; IL1RAPL1; Chromosomal microarray analysis; CNTNAP2; SHANK3; IL1RAPL1; CIENCIAS BIOLOGICAS::GENETICA

Intellectual disability (ID) is characterized by significant impairment in both cognitive and adaptive functions, originating before the age of 18 years. In addition, it is a common phenotype sign in a cluster of heterogeneous syndromic or non-syndromic disorders, associated with some comorbidities such as autism and congenital malformations. In the worldwide, ID affects around 1–3% of the general population and in Brazil ID affects approximately 0.8% of the population. The Copy number variations account for about 15– 20% of children with unexplained ID, compromising the functioning of several genes, with more than 1,416 genes described as causative of this phenotype sign. The aim of the study was to evaluate the occurrence of CNVs, identified by CMA with the size filter of < 100 kb, harboring genes functionally associated with ID in patients from SUS with a clinical diagnosis of ID referred for the genetic diagnosis. During January 2013 to December 2016, GTG banding karyotype was performed in 325 patients with ID, achieve the genetic diagnostic in 57.2%, demonstrating to be an important screening approach for patients with DI. However, 42,8% of the patients showed the karyotype with no visible numerical or structural alterations. The CMA analysis with the size filter of ≥ 100 kb was performed in these patients, where it was possible to elucidate the genetic diagnose in 29.8% of the patients, demonstrating 7,1 % of the increment on the diagnostic. All the cases remained without a diagnosis were submitted to the CMA analysis with size filter of < 100 kb, where it was identified loss CNVs in regions harboring CNTNAP2, FGF13, MID1, MID2, SHANK3, IL1RAPL1, DMD, and PAK3 genes. The reduction of the size filter demonstrated an increase of 12% in the ratio of diagnosis, expanding the spectrum of CNVs identification in regions which harboring genes related to the clinical manifestation of ID. The application of both GTG banding and CMA with the size filter of ≥ 100 kb and later the size filter of < 100 kb allowed an increase in the genetic diagnosis of ID and comorbidities, giving a broad understanding of the genetic aspects related to these conditions and allowing the adequate management of families. Finally, the genetic counseling provides a better understanding of the genetic causes of ID, the familial implications of the genetic contribution and the chance of recurrence.