title: Male with mosaicism for supernumerary ring X chromosome: analysis of phenotype and characterization of genotype using array comparative genome hybridization.
abstract: Supernumerary, derivative, and ring X chromosomes are relatively common in Turner syndrome females but have been reported rarely in males. To date, less than 10 cases have been published, of which only 2 have been partially characterized in defining the breakpoints and genetic content of the derivative X chromosome. We describe a male with mosaicism for a supernumerary X chromosome (46,XY/47,XY, r(X)) who has multiple congenital anomalies, including features of craniofrontonasal dysplasia (Mendelian Inheritance in Man 304110) and the presence of ectopic female reproductive organs. Using comparative genomic hybridization array mapping, we determined that the derivative X is composed of a 24-Mb fragment that contains the regions Xp11.3 through Xq13.1 and lacks the XIST gene. This is the first report to describe a detailed molecular characterization of a ring X chromosome in a male by comparative genomic hybridization array analysis. We compare the clinical and molecular findings in this patient to other 46,XY, r(X) patients reported in the literature and discuss the potential role of disomy for known genes contained on the ring X chromosome.
authors.affiliation: Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, Colorado, USA.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Baker
authors.forename: Anne Chun-Hui
authors.initials: AC
authors.lastname: Tsai
authors.forename: Michelle
authors.initials: M
authors.lastname: Springer
authors.forename: Karen
authors.initials: K
authors.lastname: Swisshelm
authors.forename: Jennifer
authors.initials: J
authors.lastname: March
authors.forename: Kathleen
authors.initials: K
authors.lastname: Brown
authors.forename: Gary
authors.initials: G
authors.lastname: Bellus
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D041321:Chromosomes, Human, X; D002658:Developmental Disabilities / Q000235:genetics; D004303:Dosage Compensation, Genetic; D005145:Face / Q000002:abnormalities*; D005838:Genotype; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008297:Male; D046228:Microarray Analysis; D009030:Mosaicism; D010641:Phenotype; D012303:Ring Chromosomes