Fragile X syndrome screening in pregnant women and women planning pregnancy shows a remarkably high FMR1 premutation prevalence in the Balearic Islands

Ramona Alfaro Arenas, Jordi Rosell Andreo, Dami Heine Suñer, María Pía Cordero, Consuelo Fernández Yagüe, Catalina Cerdá, Jerónima Amengual, Margalida Lladó, Elena Pascual de Juan, Teresa Mariscal, Pilar López Redondo, Olga Román, Andrés Calvo Pérez, Sabine Rehkugler, Francisco Javier Agüera, Azucena Bande Seisdedos, Jesüs Fernández Castaño, Roser Gallardo Ferrer, Margalida Alomar Castell, Concha Manzanares MirCarmen Carrascosa Martín, Teresa Sánchez-Puga Crusat, Joana Crespí Rullan, Catalina Serra Calafat, Catalina Artigues Mascaró, Antonia Cladera Riera, Joana Guardiola Martínez, Margalida Pujol Ferragut, Rocío Aguilar González, Miquel Juan Clar, Albert Tubau, Maria Antonia Ferragut, Elena Portells Miralles, Carmen Ribera Gómez, Jessica Holster, Elena Montes de Oca, Dolores García, Carmen Vallejo Burgada, Agustín Hernández, Juan Trias Rojas, Ines Pomar, Joana Boyeras, Eva Navarro, Yolanda Vives Fuster, María Maimó Vaquer, Mariana Garces Más, Matteu Taylor, Silvia Miralles Corrales, Marian GarcíaBaratas, María A. Blanco García, Group for the study of FXS in the Balearic Islands

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


There are no reported studies to determine incidence of Fragile X Syndrome (FXS) in women within the Spanish population. For this reason, together with the high incidence of FXS in the general population, the exclusively maternal expansion, the familial and social impact of the syndrome, and the ease of use and level of detection of current PCR-based techniques, we have conducted a population-based screening pilot program of which we present here the molecular results. We typed prospectively 3,413 pregnant and 318 non-pregnant women and found a prevalence of premutation (PM) carriers of 1 in 106, which is the highest described to date in any population. We also found 230 different alleles of which the most frequent are 10A9A9 (38.4%), 9A9A9 (15.1%), and 10A9 (10.5%). Furthermore, alleles with 0 AGG interruptions or with a pure (uninterrupted) CGG repeat run larger than 34 (presumably more unstable), were more frequent among PM alleles compared to normal alleles. Theà unexpected high frequency of expanded PM alleles in females in the general population makes a very compelling argument for the need for prenatal or preconceptional FXS screening in our community. Furthermore, we find FMR1 triplet primed PCR (TP-PCR) confidently and precisely determines sizes for both alleles of the CGG repeat in women and offers AGG information which greatly improves CGG expansion risk estimations for genetic counselling. Thus, TP-PCR is an informative, efficient and robust method for FXS screening in the female population.

Original languageEnglish (US)
Pages (from-to)1023-1031
Number of pages9
JournalAmerican Journal of Medical Genetics, Part B: Neuropsychiatric Genetics
Issue number8
StatePublished - Dec 1 2016


  • FMR1 gene
  • intellectual disability
  • neurogenetic disorder
  • premutation
  • prenatal screening

ASJC Scopus subject areas

  • Genetics(clinical)
  • Psychiatry and Mental health
  • Cellular and Molecular Neuroscience


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