Successful child development is determined by several factors, including a child’s genotype. Any deviations to the normal 46 chromosomes, can result in chromosomal disorders or more specifically Copy Number Variant (CNV) disorders. CNV disorders are diagnosed when there is sub-microscopic variance within the chromosomal structure, resulting in either a deletion or duplication to genetic material. The exact implications of CNVs for child development are unknown, although there is good evidence to suggest children are phenotypically developmentally delayed. Alongside this, there is a relatively well-developed understanding of the profiles of more common CNV locations and syndromes. Based on this, it was of interest to understand how CNVs ‘in general’ impact children’s cognitive, motor and behavioural development.
Children and families aged 7-16 years with a diagnosed CNV (via NHS Clinical Genetics collaboration) were recruited and completed a range of standardised assessments (Chapter 2). The feasibility of setting up a clinical project, recruiting a paediatric sample and implementing assessments within the home are discussed in Chapter 3. Chapters 4-6 present a descriptive analysis of the full sample with a range of exploratory investigations. Broadly, children with a CNV present below average cognitive and motor development with elevated behavioural symptoms typical of neurodevelopmental disorders (Chapter 4). A complex profile is found in comparison to unaffected sibling and twin controls (Chapter 5) while approximately 50% show similarities to children with a statement of special educational provision (Chapter 6).
Despite the complex genotype and phenotype relationship, having a CNV irrespective of the: location (CNVs at neurodevelopmental disorder susceptibility loci), type (deletion or duplication), size and number of CNV may risk atypical development. These findings may support awareness and understanding of genetic variance and the impact for a developing child system. This may benefit educational settings, children and families as theoretical and practical implications will be discussed.
