Induction of the fra(X) in amniotic fluid cells by excess thymidine

Tommerup, Niels

doi:10.1002/ajmg.1320300147

Cited by 3 publications

(2 citation statements)

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“…Discordance between cytogenetic and RFLP data was observed in one male fetus (P8), in which the fragile site was not demonstrated in 230 CV cells analysed; however, the linkage data favoured that the fetus had inherited the fragile X mutation (Figure 2c). Following genetic counselling, the parents opted for termination; however, the fragile X could not be demonstrated in either fetal lymphocytes or in amniotic fluid cells obtained prior to termination (Tommerup, 1988).…”

Section: Resultsmentioning

confidence: 99%

“…From P26 the initial use of collagenase for dispersion of the tissue (Tommerup et al, 1985) was replaced by treatment with (Tommerup et al, 1985), so this inhibitor was not used subsequently. Addition of excess thymidine (dT) Tommerup, 1988), 150 and 300 mg/l for 24 h, was introduced from P5 following an initial successful testing on thawed CV cells from P1 and from ten control samples (data not shown). From P18, the culture treated with MTX was abolished due to a very low mitoticindexin severalcases, and replacedwith a3 additionalculture treated with excess dT (75 mg/l).…”

Section: Methodsmentioning

confidence: 99%

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Early prenatal diagnosis of the fragile site AT Xq27.3 associated with Martin‐Bell syndrome

et al. 1991

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Early prenatal diagnosis of the fragile X was attempted in 44 pregnancies, including one twin pregnancy at risk of Martin-Bell (MB) syndrome. The sex ratio was 24M:21F. The fragile site was reproducibly demonstrated in cultured chorionic villus (CV) cells in eight male and five female fetuses. Six of the male and three of the female fetuses were terminated. Simultaneous RFLP analysis provided confirmative data with flanking DNA markers in 3 of 13 analysed cases. Recombination and/or non-informativeness at available distal and/or proximal loci were found in nine cases. In one male fetus, discordance between the haplotype and cytogenetics (fragile-X-negative) suggested the presence of a normal male transmitter, a double meiotic cross-over within the region, or a false-negative cytogenetic diagnosis. However, discordance between prenatal and post-termination/postnatal cytogenetic findings was not observed in this series. The use of excess thymidine for induction of the fragile X in cultured CV cells provided in the majority of cases a safe and rapid method for cytogenetic diagnosis, with options for early induced termination in fragile-X-positive pregnancies, for simultaneous RFLP analysis, and for subsequent second-trimester analysis of fetal blood in complicated cases.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%