Mosaicism

Effect of chromosome constitution variations on the expression of Turner phenotype

A. V. S. Bispo, Santos, L. Odos, Burégio-Frota, P., Galdino, M. B., Duarte, A. R., Leal, G. F., Araújo, J., Gomes, B., Soares-Ventura, E. M., Muniz, M. T. C., and Santos, N., Effect of chromosome constitution variations on the expression of Turner phenotype, vol. 12, pp. 4243-4250, 2013.

Turner syndrome (TS) is a chronic disease related to haploinsufficiency of genes that are normally expressed in both X chromosomes in patients with female phenotype that is associated with a wide range of somatic malformations. We made detailed cytogenetic and clinical analysis of 65 patients with TS from the region of Recife, Brazil, to determine the effects of different chromosome constitutions on expression of the TS phenotype. Overall, patients with X-monosomy exhibited a tendency to have more severe phenotypes with higher morbidity, showing its importance in TS prognosis.

Identification of a de novo inv dup(X)(pter→ q22) by multicolor banding in a girl with Turner syndrome

P. Burégio-Frota, Valença, L., Leal, G. F., Duarte, A. R., Bispo-Brito, A. V. S., Soares-Ventura, E. M., Marques-Salles, T. J., Nogueira, M. T. M. C., Muniz, M. T. C., Silva, M. L. M., Hunstig, F., Liehr, T., and Santos, N., Identification of a de novo inv dup(X)(pter→ q22) by multicolor banding in a girl with Turner syndrome, vol. 9. pp. 780-784, 2010.

We report on a 23-year-old girl with short stature, short and wide neck, low posterior hairline, hypogonadism, underdeveloped breasts, infantile uterus, ovaries not visualized, and primary amenorrhea. Cytogenetic G-banding analysis revealed a mosaic karyotype of 46,X,dup(X)(q22)[35]/45,X[15], confirming the clinical suspicion of Turner syndrome. Molecular cytogenetics using a multicolor banding probe set for the X-chromosome characterized an inverted dup(X). The karyotype of the patient was therefore interpreted as 46,X,inv dup(X) (pter → q22::q22 → pter).

FISH, PCR and cytogenetic characterization in a girl with ambiguous genitalia and karyotype mos46,X,iso(Y)(qter→p11.3::p11.3→qter)[80]/45,X[17]/46,X,+mar[3]

S. R. F. Pereira, Pereira, A. C. N., Souza, M. T. V. L., and Ramos, M. R. B. P., FISH, PCR and cytogenetic characterization in a girl with ambiguous genitalia and karyotype mos46,X,iso(Y)(qter→p11.3::p11.3→qter)[80]/45,X[17]/46,X,+mar[3], vol. 7, pp. 1089-1096, 2008.

A cytogenetic study was carried out in a girl with virilized external genitalia, who showed a karyotype containing a Y isochro isochromosome in mosaic form: mos46,X,iso(Y)(qter→p11.3::p11.3→qter)[80]/45,X[17]/46,X,+mar[3]. The chromosome aberrations were confirmed by fluorescence in situ hybridization analysis, with both whole chromosome paint Y probe and centromeric X chromosome probe. The molecular analyses by PCR detected the presence of the SRY, DAZ and AMGY genes, confirming the presence of the whole long arm and almost whole short arm of the Y chromosome.

Molecular analysis of an idic(Y)(qter→p11.32::p11.32→qter) chromosome from a female patient with a complex karyotype

R. Fernandez and Pasaro, E., Molecular analysis of an idic(Y)(qter→p11.32::p11.32→qter) chromosome from a female patient with a complex karyotype, vol. 5, pp. 399-406, 2006.

A female patient with a structurally abnormal idic(Y) (p11.32) chromosome was studied using fluorescence in situ hybridization and PCR to define the precise position of the breakpoint. The patient had a complex mosaic karyotype with eight cell lines and at least two morphologically distinct derivatives from the Y chromosome. The rearrangement was a result of a meiosis I exchange between sister chromatids at the pseudoautosomal region, followed by centromere misdivision at meiosis II.

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