Genetic analysis and prenatal diagnosis of intellectual disability caused by Xq25 microduplication in a pedigree / 中华围产医学杂志

ABSTRACT

Objective:To analyze the clinical and genetic characteristics of a 27-year-old male patient with intellectual disability and his pedigree to provide a reference for genetic counseling and prenatal diagnosis.Methods:G-banding and array comparative genomic hybridization (aCGH) were performed to analyze the karyotypes and genomic copy number variations of the proband (Ⅲ-1) and his family members. Based on the results, prenatal diagnosis was performed for one pregnant woman (Ⅲ-2) in the pedigree who is the sister of the proband.Results:All karyotyping were normal in the family members, while aCGH results showed a 1 533 kb microduplication in the Xq25 region of the proband, his mother (Ⅱ-3), his uncle (Ⅱ-2), and his sister (Ⅲ-2), which was confirmed to be pathogenic. The proband and his uncle presented with intellectual disability, bradylalia, and facial dysmorphism. In contrast, his mother and sister showed normal phenotypes. His sister's fetal karyotype and aCGH results were normal, and the pregnancy continued. A male baby (Ⅳ-1) was delivered vaginally at term and showed no physical or intellectual abnormalities during a 46-month follow-up.Conclusions:Xq25 microduplication might be the cause of intellectual disability in the proband. STAG2 is probably the essential gene in Xq25 region.