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Molecular detection of XO - Turner syndrome
Turner syndrome is caused by haploinsufficiency of the short arm of X-chromosome, and is usually diagnosed by karyotyping. This procedure is time-consuming, expensive and unfeasible for population screening. We propose molecular detection of 45XO Turner patients based on the ability of HpaII, a meth...
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Published in: | Genetics and molecular research 2002-09, Vol.1 (3), p.266-270 |
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Main Authors: | , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | Turner syndrome is caused by haploinsufficiency of the short arm of X-chromosome, and is usually diagnosed by karyotyping. This procedure is time-consuming, expensive and unfeasible for population screening. We propose molecular detection of 45XO Turner patients based on the ability of HpaII, a methylation sensitive endonuclease, to induce the cleavage of non-methylated DNA in the active X-allele. Genomic DNA was obtained from 22 patients with Turner syndrome confirmed by karyotype (45XO, N = 18; 45XO/46XX, N = 4). After digestion, DNA was amplified with primers directed to exon 1 of the androgen receptor (AR) gene and to the GAPDH control gene. Normal control females or mosaic patients, with a second methylated X-chromosome, escaped from HpaII digestion and produced a band corresponding to AR gene amplification. 45XO patients have just one active non-methylated X-chromosome, completely digested by HpaII, thus preventing the amplification of the AR gene. Three of the 45XO cases gave amplified bands, suggesting low-frequency mosaicisms that are not detected by karyotyping. Compared to classical karyotype studies for the detection of 45XO Turner patients, this new molecular method is simpler, faster and less expensive. |
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ISSN: | 1676-5680 |