Array comparative genome hybridization in patients with developmental delay: two example cases

Area of Science:

• Genetics
• Neurodevelopmental Disorders
• Genomic Analysis

Background:

• Developmental delay is a predictor of intellectual disability (ID) and autism spectrum disorder (ASD), impacting intellectual and social functioning.
• The genetic underpinnings of ID and ASD are complex, with specific genetic defects identified in only a fraction of affected individuals.
• Copy number variants (CNVs) are increasingly recognized as significant contributors to these neurodevelopmental conditions.

Observation:

• Array comparative genome hybridization (aCGH) is a powerful genomic tool for detecting submicroscopic chromosomal gains or losses.
• aCGH can refine the characterization of cytogenetically visible rearrangements and identify novel pathogenic CNVs.
• Case studies illustrate aCGH's utility in diagnosing genetic causes of developmental disorders.

Findings:

• Patient 1 with a visible X chromosome deletion had their gene content precisely mapped by aCGH, aiding prognosis.
• Patient 2, with a normal karyotype, was found to have a small recurrent deletion on chromosome 1 responsible for their phenotype.
• These findings highlight the role of CNVs in developmental delay, ID, and ASD.

Implications:

• Genomic analysis using aCGH is crucial for diagnosing the underlying causes of developmental delay, ID, and ASD.
• Identifying specific genetic defects improves diagnostic accuracy and can inform prognosis and potential interventions.
• Understanding the genetic heterogeneity of these disorders is essential for advancing research and clinical management.