Genomic imbalances in patients with intellectual disability

• Autor(a) principal: Lopes, Fátima Daniela Teixeira
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/7645
• topic: Biotecnologia; Atraso mental; Genómica; Psicopatologia

Development delay/Intellectual disability (DD/ID) is a serious and life-long condition which represents a challenge for families and public health services. It is characterized by suboptimal functioning of the central nervous system resulting in limitations both in intellectual functioning and in adaptive behavior, and it is observed in approximately 2-3% of the population worldwide. Establishing the disease etiology is important for clinical management, genetic counseling and coping strategies of the families. Array-based comparative genomic hybridization technique (aCGH), also called molecular karyotyping (MC), allows us to directly measure genomic copy number variations between the patient and a control DNA. The whole genome of an individual is represented in a high-resolution “virtual karyotype”, allowing the detection of submicroscopic alterations, undetectable by standard or highresolution karyotyping techniques. In Portugal, the guidelines for testing patients with DD/ID indicate the Gbanding karyotyping in first place and, whenever the result is normal, testing for the most common single gene disorders (Fragile X, for instance), for subtelomeric rearrangements and with specific FISH probes. However, the latter technologies are not suitable for whole genome scans in routine diagnosis, both because of the lower resolution levels (the case of conventional karyotyping), the extensive time consumption and high costs (the FISH case). The introduction of aCGH should contribute to the etiological classification of a large proportion of the DD/ID patients as well as to conclude about the utility of using these technologies for diagnosis of idiopathic DD/ID in the clinical context.