Cytogenetic Findings in Children With Dysmorphic Features and Intellectual Disability/Mental Retardation in Eastern Croatia

Abstract

Introduction: Numerical and structural chromosomal aberrations are some of the most common causes of intellectual disability/mental retardation (ID/MR), especially syndromic, and they represent about 10% of ID/MR that can be detected using cytogenetic methods. Aim: The aim of this study is to show the results of cytogenetic findings in 340 patients with ID/MR and dysmorphia and/or multiple malformations in Eastern Croatia, examined at the Paediatric Clinic of the Clinical Hospital Centre Osijek and the Medical Genetics Laboratory at the Faculty of Medicine Osijek. Methods: Cytogenetic analysis of 340 samples from patients with ID/MR and/or dysmorphia was conducted using G-banding with Trypsin/Giemsa (GTG) and fluorescent in situ hybridization (FISH). Results: A total of 340 patients with ID/MR with dysmorphia and/or multiple malformations were referred for cytogenetic evaluation. The age range of patients was 0-18 years. The analysis included 221 boys (65%) and 119 girls (35%). A chromosomal aberration was found in 24.5% of patients. Numerical aberrations (aneuploidy) were seen in 64 patients (18.8%). The most common type of autosomal aneuploidy was trisomy 21, found in 14.7% of patients. Sex chromosome aneuploidy was detected in 2.6% of patients. Structural abnormalities were found in 6.5% of patients. Conclusion: The results of our study show that cytogenetic analysis in patients with ID/MR should nowadays be applied when aneuploidies are suspected, since the first-line genetic test for patients with ID/MR, especially non-syndromic, is the Array Comparative Genomic Hybridization (aCGH).

Keywords

• intellectual disability/mental retardation
• chromosomal aberrations
• cytogenetic
• children