Clinical and genetic study of a child with 15q11.2 microduplication

OBJECTIVE: To explore the genetic basis of a child with developmental delay and intellectual disability. METHODS: Peripheral blood samples of the child and his parents were collected for routine G-band karyotyping analysis and single nucleotide polymorphism array (SNP array) assay. Amniotic fluid sample was collected during the next pregnancy for prenatal diagnosis. RESULTS: No karyotypic abnormality was found in the child and his parents. SNP array showed that the child has carried a 855.3 kb microduplication in 15q11.2. His mother carried the same duplication but had no phenotypic anomaly. No microdeletion/microduplication was found in his father. Upon prenatal diagnosis, no abnormalities was found with the chromosomal karyotype and SNP array result of the fetus. CONCLUSION: 15q11.2 microduplication may result in developmental delay and intellectual disability, for which CYFIP1 may be a candidate gene. However, the duplication may increase the risk but with a low penetrance. This should attract attention during clinical consultation.