Purpose and scope The aim of this position statement is to provide recommendations for clinicians regarding the use of genetic and metabolic investigations for patients with neurodevelopmental disorders (NDDs), specifically, patients with global developmental delay (GDD), intellectual disability (ID) and/or autism spectrum disorder (ASD). This document also provides guidance for primary care and non-genetics specialists caring for these patients while awaiting consultation with a clinical geneticist or metabolic specialist.
Methods of statement development A multidisciplinary group reviewed existing literature and guidelines on the use of genetic and metabolic investigations for the diagnosis of NDDs and synthesised the evidence to make recommendations relevant to the Canadian context. The statement was circulated for comment to the Canadian College of Medical Geneticists (CCMG) membership-at-large and to the Canadian Pediatric Society (Mental Health and Developmental Disabilities Committee); following incorporation of feedback, it was approved by the CCMG Board of Directors on 1 September 2022.
Results and conclusions Chromosomal microarray is recommended as a first-tier test for patients with GDD, ID or ASD. Fragile X testing should also be done as a first-tier test when there are suggestive clinical features or family history. Metabolic investigations should be done if there are clinical features suggestive of an inherited metabolic disease, while the patient awaits consultation with a metabolic physician. Exome sequencing or a comprehensive gene panel is recommended as a second-tier test for patients with GDD or ID. Genetic testing is not recommended for patients with NDDs in the absence of GDD, ID or ASD, unless accompanied by clinical features suggestive of a syndromic aetiology or inherited metabolic disease.
- genetics, medical
- clinical decision-making
- genetic testing
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Correction notice This article has been corrected since it was published online first. The placement of tables 2 and 3 has been corrected within the article.
Contributors MTC, MS and HV were responsible for identifying the literature, summarising subgroup meetings and drafting their test-specific sections. MTC, HV and HH were responsible for drafting the manuscript. All authors contributed to literature review, the conception and design of the position statement, interpretation of data, writing and critical revisions contributing to the intellectual content and approval of the final version of the manuscript.
Funding HH was supported with funding from the Canadian College of Medical Geneticists. SMEL is supported by an Investigator Grant Award through BC Children’s Hospital Research Institute.
Competing interests TNN: spouse employed by Illumina.
Provenance and peer review Not commissioned; externally peer reviewed.