[Turner syndrome and mosaicism].
Turner's syndrome is a gonadosomatic dysgenesis of female phenotype due to a more or less complete monosomy of one of the X chromosomes leading to a haploinsufficiency of the development genes situated at the level of the pseudoautosomal region of the gonosomes. Further experience of the karyotype showed a preponderance of mosaics and considerable variability of Turner's phenotype in proportion to the number of 45, X cells. The rare cases of monozygotism discordant with variable tissular distribution mosaics show that the phenotypic expression is a genic dosage effect. In patients with TS it would thus be of interest to study a second tissue such skin fibroblasts when a discordance is observed between the phenotype and the karyotype.
Battin
Jacques
J
Service de Génétique Médicale-Hôpital des Enfants-CHU Pellegrin-Place Amélie Raba-Léon-33076 Bordeaux.
D000015:Abnormalities, Multiple / Q000235:genetics; D041321:Chromosomes, Human, X / Q000235:genetics; D004200:Diseases in Twins / Q000235:genetics; D004303:Dosage Compensation, Genetic; D005260:Female; D006130:Growth Disorders / Q000235:genetics; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics; D009030:Mosaicism; D009928:Organ Specificity; D010641:Phenotype; D014424:Turner Syndrome / Q000235:genetics* / Q000473:pathology; D014430:Twins, Monozygotic