P128 A retrospective audit of microarray testing performed in the developmental clinic at a tertiary paediatric centre. (June 2019)

• Record Type: Journal Article
• Authors: McGrath, Thomas; Kelly, Stephanie; Gallagher, Louise; Curtis, Emma
• Is Part Of: Archives of disease in childhood. Volume 104:(2019)Supplement 3
• Page Start: A207
• Page End: A207
• Publication Date: 2019-06
• Subjects: Children -- Diseases -- Periodicals; Infants -- Diseases -- Periodicals; 618.920005
• DOI: 10.1136/archdischild-2019-epa.483
• Languages: English
• ISSNs: 0003-9888

Abstract

Abstract : Background: Array comparative genomic hybridisation (microarray) testing is a high resolution genetic test which detects microscopic and sub-microscopic chromosomal aberrations 1 . In recent years, it has become the first line genetic investigation in children presenting to paediatric services with unexplained global developmental delay (DD), intellectual disability (ID) and autism spectrum disorders (ASD) 1, 2 . Previous studies have shown that the diagnostic yield of microarray testing is between 15 and 20% 2 . Objectives: The aim of this retrospective audit was to investigate the use of microarray testing of children presenting to a specialist developmental clinic, comparing the clinical indication against proposed national and international guidelines 1, 2, as well as, documenting abnormal results identified and their correlation with clinical phenotype with a view to refining the screening protocol. Methods: A total of 164 microarray tests performed on patients presenting to the clinic in 2017 were reviewed. The clinical indication prompting testing was documented. The overall number of copy number variants in the population studied was determined and each CNV was characterised and its clinical significance assessed.All results had previously been disclosed to patients and families and all data anonymised. Results: The most common clinical indications for the 164 microarray tests included ASD, DD, and speech and language delay accounting for 99, 26, and 11 cases respectively.Other less common indications included gross motor delay, ID, and developmental coordination disorder (< 10).A total of 42 copy number variants were identified in 36 (29%) patients. Of the 42, 16 (9.8%) were associated with a previously documented genetic abnormality on the Online Mendelian Inheritance in Man database, 3 (1.8%) were variations of unknown significance and 23 (14%) were benign copy number variants (BCNV). Of the 99 children with autism, 19 (19.2%) demonstrated a genetic aberration 8 (8.1%) of which were previously described on the OMIM database, 1 (1%) was a variation of unknown significance and 8 (8.1%) were BCNVs. Conclusion: Advances in genetic testing have transformed investigation in children with developmental abnormalities and there is an expectation that such investigations will be performed. Within the group of children with a diagnosis of autism, the explanation and understanding of the abnormality can be difficult. This presentation will explore further the clinical phenotype and genetic results of the children in this study with discussion regarding guidance for genetic testing in this patient group.