Classification of Brain Magnetic Resonance Imaging Abnormalities and Spectrum of Neurological Findings in a Cohort with Copy Number Variation-Related Disorders

Abstract

Introduction: Copy number variation (CNV) is the difference in the sequence of genomic segments, which can vary from one kilobase to several megabases. Certain CNVs have been linked to various human disorders, such as intellectual disability, multiple congenital anomalies, autism spectrum disorders, neurodegenerative and neuropsychiatric conditions, and cancer. The present study aims to classify brain magnetic resonance imaging (MRI) findings, describe neurological manifestations, and discuss the findings within the context of genotype–phenotype correlations in a cohort of patients with recurrent and nonrecurrent CNVs. Methods: A total of 21 patients with pathogenic CNV detected using microarray analysis were included in the study. Results: Analysis of the clinical findings of the patient cohort showed that 16 (76%) had microcephaly, 14 had epilepsy (66%), 20 had facial dysmorphism (95%), and all had developmental delay (100%). Novel brain MRI findings were detected in six (6/13, 46%) patients with recurrent CNV and five (5/8, 63%) patients with nonrecurrent CNV. Conclusion: CNV-related disorders should be considered in the differential diagnosis of patients with brain MRI findings suspicious for metabolic disorders. Brain MRI differences in patients with the same chromosomal deletion can be explained by the second-hit hypothesis. Additional single nucleotide variations and epigenetic factors in these cases may have led to the involvement of different regions of the brain. Revealing the phenotypic and genotypic characteristics of cases in rare disorders will contribute to the widespread use of precision medicine and genetic treatment approaches in the near future.