Molecular genetic analysis of a child with de novo 16p11.2 microdeletion

OBJECTIVE To explore the genetic basis for a child featuring developmental delay, intelligent disability and language deficit. METHODS Peripheral blood samples of the child and her parents were collected for routine G-banding karyotyping analysis and single nucleotide polymorphism array (SNP array) detection. Amniotic fluid was also sampled from the mother for karyotyping analysis and SNP array detection. RESULTS No karyotypic abnormality was found with the child and her parents. SNP array showed that the child has carried a 761.4 kb microdeletion at 16p11.2, while her mother has carried a 444.4 kb microduplication at 15q13.3. Her father's result was negative. Further analysis showed that the 15q13.3 microduplication was inherited from her maternal grandfather who was phenotypically normal. Prenatal diagnosis showed that the fetus has inherited the15q13.3 microduplication from its mother. CONCLUSION The child has carried a de novo 16p11.2 microdeletion, which overlaps with 16p11.2 microdeletion syndrome region, in addition with similar clinical phenotypes. The 16p11.2 microdeletion probably underlies her abnormal phenotype.