A dynamic study in two new cases of X chromosome translocations.
The authors discuss the clinical and cytogenetic problems raised in two new cases of X-chromosome translocations. The first case involves a child who presented marked malformations at age 3 months. Chromosome analysis revealed the presence of a translocation between a 22 and X chromosome resulting in partial X monosomy and partial trisomy 22: 46,X,der(X),t(X:22)(q112;q13)mat. The balanced translocation form was detected in the mother. Dynamic study after 5-Brdu treatment revealed inactivation of the translocated X chromosome in the proband, while in the mother the normal X chromosome was inactivated. In addition to magnesium dependent hypocalcemia resulting from a specific absorption anomaly, Case 2 presented discrete malformations and psychomotor retardation. Chromosome analysis revealed an apparently balanced translocation between a 9 and X chromosome: 46,X,t(9;X)(q12;p22). Treatment with 5-Brdu demonstrated that the translocated X chromosome was inactivated but that inactivation did not extend to the translocated part of chromosome 9. Finally, a pericentric inversion of a 9 chromosome was detected in the father, grandfather, and brother of the proband.
D001973:Bromodeoxyuridine; D002904:Chromosomes, Human, 21-22 and Y; D002906:Chromosomes, Human, 6-12 and X; D005145:Face / Q000002:abnormalities; D005260:Female; D006130:Growth Disorders / Q000235:genetics; D006801:Humans; D006996:Hypocalcemia / Q000235:genetics; D007223:Infant; D007231:Infant, Newborn; D007621:Karyotyping; D010375:Pedigree; D011596:Psychomotor Disorders / Q000235:genetics; D012729:Sex Chromosome Aberrations / Q000175:diagnosis*; D014178:Translocation, Genetic; D014960:X Chromosome
D001973:Bromodeoxyuridine