title: Ring chromosome 18q and jumping translocation 18p in an adult male with hypergonadotrophic hypogonadism.
abstract: Constitutional jumping translocations (JT) are rare, especially in phenotypically normal individuals. We report on an adult male with partial hypogonadism as the sole phenotypic abnormality with an unusual chromosome abnormality. In this patient, centric fission of chromosome 18 lead to formation of a ring 18q chromosome, while 18p formed a JT through centromere-telomere fusion with chromosome 8q (66%) or 20q (13%). In 21% of cells, the 18p fragment was missing. Fluorescent in situ hybridization revealed the presence of interstitial telomeres at the junction site of the fusion and unequal distribution of the alphoid sequences through the centric fission, leaving a small, yet functional centromere within the ring. We discuss the phenotype of the patient in light of this unusual karyotype.
authors.affiliation: Cytogenetics Laboratory, Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Beirut, Lebanon. lailaz@aub.edu.lb
authors.forename: L
authors.initials: L
authors.lastname: Zahed
authors.forename: G
authors.initials: G
authors.lastname: Oreibi
authors.forename: C
authors.initials: C
authors.lastname: Azar
authors.forename: I
authors.initials: I
authors.lastname: Salti
mesh_terms: D000328:Adult; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007006:Hypogonadism / Q000097:blood / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D009845:Oligospermia / Q000097:blood / Q000235:genetics; D012303:Ring Chromosomes; D013739:Testosterone / Q000097:blood; D014178:Translocation, Genetic
chemical_list: D013739:Testosterone; D005640:Follicle Stimulating Hormone