These authors contributed equally to this work.
Frequency of FMR1 premutation carriers and rate of expansion to full mutation in a retrospective diagnostic FMR1 Korean sample
Article first published online: 13 JUN 2013
© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Volume 85, Issue 5, pages 441–445, May 2014
How to Cite
Jang, J.-H., Lee, K., Cho, E.-H., Lee, E.-H., Kim, J.-W. and Ki, C.-S. (2014), Frequency of FMR1 premutation carriers and rate of expansion to full mutation in a retrospective diagnostic FMR1 Korean sample. Clinical Genetics, 85: 441–445. doi: 10.1111/cge.12195
There is no conflict of interest with any financial organization.
- Issue published online: 1 APR 2014
- Article first published online: 13 JUN 2013
- Accepted manuscript online: 17 MAY 2013 01:02PM EST
- Manuscript Revised: 15 MAY 2013
- Manuscript Accepted: 15 MAY 2013
- Manuscript Received: 6 FEB 2013
- Samsung Biomedical Research Institute grant. Grant Number: C-B0-206-3
- fragile X syndrome;
- full mutation;
Detection of female premutation (PM) carriers of fragile X syndrome may be important in that a PM allele from the mother can expand to a full mutation (FM) when transmitted to the fetus. Although the PM carrier frequency might be different in varying populations, there is a little data on the Korean population. Furthermore, the risks of expansion to FM have not been studied in Korean PM carriers. In this retrospective study, we estimated the female PM carrier frequency and the risks of expansion to FM in Korean diagnostic samples collected for FMR1 gene testing. Of 10,241 pre-conceptional or pregnant women, 13 PM [1 in 788; 95% confidence interval (CI), 1/1 250–1/455] and 75 intermediate allele carriers (1 in 137; 95% CI, 1/172–1/110) were identified. In 26 prenatal diagnoses cases, the PM allele was transmitted to the fetus in 13 pregnancies (50%), and five of these expanded to FM. All of the maternal alleles exceeding 70 repeats expanded to FM. In conclusion, the PM frequency in Korean diagnostic samples was lower than that reported in Western populations, while the risk for FM expansion in alleles exceeding 70 repeats might be higher than expected based upon previous reports.