What causes the abnormal phenotype in a 49,XXXXY male?
- 39 Downloads
The chromosome replication pattern of a man with 49,XXXXY was analyzed using 3H-thymidine and autoradiography as well as BrdU and acridine orange. The former technique showed a highly irregular replication pattern; the latter revealed one early replicating X chromosome, and the other three more or less asynchronously replicating. Two hypotheses seem to explain best the abnormal phenotype of males with an XXXXY sex chromosome constitution: (1) The number of the always active regions (tip of Xp) and of the possibly always active regions (the Q-dark regions on both sides of the centromere) is increased from one to four. (2) The replication pattern of the late-replicating X chromosomes is highly asynchronous, which might affect the phenotype. The possibility that more than one X chromosome might remain active in some cells, an even more abnormal and obviously deleterious situation, is still open.
KeywordsInternal Medicine Active Region Metabolic Disease Acridine Acridine Orange
Unable to display preview. Download preview PDF.
- Alvesalo L, Tammisalo E (1981) Enamel thickness in 45,X females' permanent teeth. Am J Hum Genet 33:464–469Google Scholar
- Alvesalo L, Tammisalo E, de la Chapelle A (1981) Mapping of the gene(s) influencing amelogenesis in man. J Dent Res 60A:403Google Scholar
- Barlow P (1973) The influence of inactive chromosomes on human development. Humangenetik 17:105–136Google Scholar
- Fragoso R, Hernandez A, Plascencia ML, Nazara Z, Martinez y Martinez R, Cantu JM (1982) 49,XXXXX syndrome. Ann Génét (Paris) 25:145–148Google Scholar
- Lyon MF (1974) Mechanisms and evolutionary origins of variable X-chromosome activity in mammals. Proc R Soc Lond [Biol] 187: 243–268Google Scholar
- Lyon MF (1983) The X chromosomes and their levels of activation. In: Sandberg AA (ed) Cytogenetics of the mammalian X chromosome, part A, Liss, New York, pp 187–204Google Scholar
- Mikkelsen M (1976) Identification of active and inactive X chromosomes by BrdU incorporation and fluorochrome staining. In: Pearson PL, Lewis KR (eds) Chromosomes today, vol 5. Wiley, New York, pp 409–414Google Scholar
- Otto PG, Therman E (1982) Spontaneous cell fusion and PCC formation in Bloom's syndrome. Chromosoma 85:143–148Google Scholar
- Schempp W, Meer B (1983) Cytologic evidence for three human X-chromosomal segments escaping inactivation. Hum Genet 63: 171–174Google Scholar
- Therman E (1983) Mechanisms through which abnormal X chromosome constitutions affect the phenotype. In: Sandberg, AA (ed) Cytogenetics of the mammalian X chromosome, part B. Liss, New York, pp 159–173Google Scholar
- Therman E, Patau K (1974) Abnormal X chromosome in man: origin, behavior and effects. Humangentik 25:1–16Google Scholar
- Therman E, Sarto GE (1983) Inactivation center on the human X chromosome. In: Sandberg AA (ed) Cytogenetics of the mammalian X chromosome, part A. Liss, New York, pp 315–325Google Scholar
- Therman E, Sarto GE, Disteche, C, Denniston C (1976) A possible active segment on the inactive human X chromosome. Chromosoma 59:137–145Google Scholar
- Therman E, Denniston C, Sarto GE, Ulber M (1980) X chromosome constitution and the human female phenotype. Hum Genet 54:133–143Google Scholar
- Zakharov AF (1983) Pattern of DNA replication of the X chromosomes: normal and supernumerary. In: Sandberg AA (ed) Cytogenetics of the mammalian X chromosome, part A. Liss, New York, pp 357–374Google Scholar
- Zaleski WA, Houston CS, Pozsonyi J (1966) The XXXXY chromosome anomaly: report of three new cases and review of 30 cases from the literature. J Can Med Assoc 94:1143–1154Google Scholar