The relationship between clinical phenotypes and chromosomal microdeletions/duplications in pediatric neurology

Abstract

Aim: The aim of this study was to determine the diagnostic utility of chromosomal microarray analysis (CMA) in daily pediatric neurology practice and to identify the guiding clinical parameters for patients requiring this test. Material and Methods: The CMA results for 91 patients with global developmental delay/intellectual disability (GDD/ID) admitted to our pediatric neurology clinic for various reasons between 2018 and 2020 were examined. Demographical and clinical data for 34 patients (37.4%) in whom del/dup was determined at CMA and 57 patients (62.6%) with normal CMA were compared. Results: There was no statistically significant difference between two groups in terms of demographic characteristics such as age, gender, type of delivery, gestational age, etc. Dysmorphisms, hypotonia, myelination abnormalities were significantly more frequent in patients with del/dup than in patients with normal result. The frequency of macrocephaly and obesity was higher in the normal group, and that of generalized seizures was higher among epileptic patients in this group. Nineteen (55.9%) of the 34 cases who have del/dup detected at analysis were regarded as pathogenic, 15 (44.1%) as uncertain clinical significance (likely pathogenic, likely benign and no subclassification). Conclusion: Since CMA is an expensive, laborious, and time-consuming test, considering clinical parameters when requesting CMA will yield high diagnostic efficiency. A high possibility of copy number variants may be predicted in GDD/ID patients with dysmorphisms, hypotonia, and myelination delay. CMA should represent the genetic analysis of choice in pediatric neurology practice in case of no finding suggesting a different etiology in these patients.