Chromosomal microarray (CMA) analysis in infants with congenital anomalies: when is it really helpful?

BACKGROUND: Birth defects are very common, affecting two to three infants in every 100 births, and often represent a diagnostic and management challenge. The birth of a child with multiple malformations is the beginning of a complex diagnostic process, where the primary purpose is to determine a precise nosological definition. An accurate diagnosis is a key prerequisite in providing a care plan, a prognosis and genetic counselling. The poor specificity of birth defects, the aetiology and course of which can vary despite similar phenotypic patterns, often makes the diagnostic path problematic. The advent and application of high-resolution chromosomal microarray, encompassing array-based comparative genome hybridization and single-nucleotide polymorphism arrays, has led to the detection of genomic copy-number abnormalities in patients affected by multiple congenital anomalies, dysmorphisms, developmental delay and mental retardation, but who have a normal karyotype.

AIM: We discuss current guidelines and recommendations for chromosomal microarray use and how its application can help clinicians make accurate diagnoses in order to appropriately manage and treat affected newborns.

CONCLUSIONS: Current guidelines strongly support the application of chromosomal microarray analysis as a first-tier cytogenetic diagnostic test alternative to karyotyping for patients with multiple congenital anomalies, or developmental delay, intellectual disability and autism spectrum disorders.