Brief report adult patient presenting an interstitial (9) (q21.32q31.1) direct duplication resulting from the malsegregation of a paternal balanced insertional translocation

Abstract

The partial trisomy 9q syndrome is a well-defined chromosomal disorder with over 40 reported cases in the literature. However, 9q duplications derived from an insertional translocation have rarely been reported. Cytogenetic and molecular analyses using G-banding, fluorescence in situ hybridization, and single nucleotide polymorphism array were performed in a 25-year-old male patient with intellectual disability, behavioral abnormalities, speech delay, postnatal growth retardation, distinctive facial features, and pyloric stenosis. G-banding analysis showed an extra chromosome segment of unknown origin inserted into band 4q25. A 16,747,601 bp duplication of 9q21.32q31.1 inserted into band 4q25 and a balanced (4;9) insertional translocation were identified by single nucleotide polymorphism array and fluorescence in situ hybridization analysis respectively in the patient and his healthy father. A literature review was performed to refine genotype-phenotype correlation of the partial trisomy 9q syndrome. This is the first report on the molecular characterization of a partial trisomy 9q syndrome derived from an insertional translocation between nonhomologous chromosomes. Our findings provide important information for genetic counseling and prenatal diagnosis of future pregnancies in this family.