title: Ring Chromosome 9 and Chromosome 9p Deletion Syndrome in a Patient Associated with Developmental Delay: A Case Report and Review of the Literature.
abstract: Ring chromosomes have been described for all human chromosomes and are typically associated with physical and/or mental abnormalities resulting from a deletion of the terminal ends of both chromosome arms. This report describes the presence of a ring chromosome 9 in a 2-year-old male child associated with developmental delay. The proband manifested a severe phenotype comprising facial dysmorphism, congenital heart defects, and seizures. The child also exhibited multiple cell lines with mosaic patterns of double rings, a dicentric ring and loss of the ring associated with mitotic instability and dynamic tissue-specific mosaicism. His karyotype was 46,XY,r(9)(p22q34)[89]/46,XY,dic r(9; 9)(p22q34;p22q34)[6]/45, XY,-9[4]/47,XY,r(9),+r(9)[1]. However, the karyotypes of his parents and elder brother were normal. FISH using mBAND probe and subtelomeric probes specific for p and q arms for chromosome 9 showed no deletion in any of the regions. Chromosomal microarray analysis led to the identification of a heterozygous deletion of 15.7 Mb from 9p22.3 to 9p24.3. The probable role of the deleted genes in the manifestation of the phenotype of the proband is discussed.
authors.affiliation: Department of Genetics, Dr. ALM PG Institute of Basic Medical Sciences, University of Madras, Chennai, India.
authors.forename: Aswini
authors.initials: A
authors.lastname: Sivasankaran
authors.forename: Murthy K
authors.initials: MK
authors.lastname: Kanakavalli
authors.forename: Deenadayalu
authors.initials: D
authors.lastname: Anuradha
authors.forename: Chandra R
authors.initials: CR
authors.lastname: Samuel
authors.forename: Lakshmi R
authors.initials: LR
authors.lastname: Kandukuri
mesh_terms: D002675:Child, Preschool; D002872:Chromosome Deletion; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics; D002658:Developmental Disabilities / Q000235:genetics*; D005145:Face / Q000002:abnormalities; D005260:Female; D017353:Gene Deletion; D056726:Genetic Association Studies; D006330:Heart Defects, Congenital / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D059785:Karyotype; D008297:Male; D009030:Mosaicism; D012303:Ring Chromosomes; D012640:Seizures / Q000235:genetics; D013577:Syndrome