Chromosome Microarray Analysis for the Investigation of Deletions in Pediatric Movement Disorders: A Systematic Review of the Literature.

Background: Chromosome microarray analysis (CMA) can detect copy number variants (CNV) beyond the resolution of standard G-banded karyotyping. De novo or inherited microdeletions may cause autosomal dominant movement disorders. Objectives: The purpose of this study was to analyze the clinical characteristics, associated features, and genetic information of children with deletions in known genes that cause movement disorders and to make recommendations regarding the diagnostic application of CMA. Methods: Clinical cases published in English were identified in scientific databases (PubMed, ClinVar, and DECIPHER) from January 1998 to July 2019 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Cases with deletions or microdeletions greater than 300 kb were selected. Information collected included age, sex, movement disorders, associated features, and the size and location of the deletion. Duplications or microduplications were not included. Results: A total of 18.097 records were reviewed, and 171 individuals were identified. Ataxia (30.4%), stereotypies (23.9%), and dystonia (21%) were the most common movement disorders. A total of 16% of the patients demonstrated more than one movement disorder. The most common associated features were intellectual disability or developmental delay (78.9%) and facial dysmorphism (57.8%). The majority (77.7%) of microdeletions were smaller than 5 Mb. We find no correlation between movement disorders, their associated features, and the size of microdeletions. Conclusions: Our results support the use of CMA as an investigational test in children with movement disorders. As the majority of identified articles were case reports and small case series (low quality), future efforts should focus on larger prospective studies to examine the causation of microdeletions in pediatric movement disorders.