Genetic Counseling and Prenatal Diagnosis of a Maternally Inherited 15q11.2 Microduplication.

Unbalanced chromosome abnormalities (UBCA) are large genomic region variations that often result in minimal clinical effects. Copy number variants (CNVs), such as microdeletions and microduplications in 15q11.2, have been linked to various health issues, making prenatal diagnosis and genetic counselling challenging. Microdeletions and microduplications in the genomic region 15q11.2 are associated with congenital heart defects, autism, schizophrenia, epilepsy, mental retardation and developmental delay. The literature on this microduplication is confusing and extensive, which is a great difficulty for prenatal diagnosis and genetic counselling. A 35-year-old female undergoing amniocentesis at Week 19 due to advanced maternal age revealed a normal 46,XX karyotype through G-banding analysis. However, Chromosomal microarray analysis (CMA) on the same amniocytes detected a 550-Kb maternally inherited chromosomal microduplication in 15q11.2. An integrated approach combining karyotype analysis, CMA, genetic counseling, and prenatal ultrasound is crucial for the accurate prenatal diagnosis of UBCAs and CNVs.