Tejada, María-IsabelGlover, GuillermoMartínez, FranciscoGuitart, MiriamDiego-Otero, Yolanda deFernández-Carvajal, IsabelRamos, Feliciano JHernández-Chico, ConcepciónPintado, ElizabetRosell, JordiCalvo, María-TeresaAyuso, CarmenRamos-Arroyo, María-AntoniaMaortua, HiartMilà, Montserrat2015-03-102015-03-102014-05-28Tejada MI, Glover G, Martínez F, Guitart M, de Diego-Otero Y, Fernández-Carvajal I, et al. Molecular testing for fragile X: analysis of 5062 tests from 1105 fragile X families--performed in 12 clinical laboratories in Spain. Biomed Res Int; 2014:195793http://hdl.handle.net/10668/1836Journal Article; Multicenter Study;Fragile X syndrome is the most common inherited form of intellectual disability. Here we report on a study based on a collaborative registry, involving 12 Spanish centres, of molecular diagnostic tests in 1105 fragile X families comprising 5062 individuals, of whom, 1655 carried a full mutation or were mosaic, three cases had deletions, 1840 had a premutation, and 102 had intermediate alleles. Two patients with the full mutation also had Klinefelter syndrome. We have used this registry to assess the risk of expansion from parents to children. From mothers with premutation, the overall rate of allele expansion to full mutation is 52.5%, and we found that this rate is higher for male than female offspring (63.6% versus 45.6%; P < 0.001). Furthermore, in mothers with intermediate alleles (45-54 repeats), there were 10 cases of expansion to a premutation allele, and for the smallest premutation alleles (55-59 repeats), there was a 6.4% risk of expansion to a full mutation, with 56 repeats being the smallest allele that expanded to a full mutation allele in a single meiosis. Hence, in our series the risk for alleles of <59 repeats is somewhat higher than in other published series. These findings are important for genetic counselling.enAlelosSíndrome del cromosoma X frágilFrecuencia génicaPruebas genéticasSistema de registrosEspañaMedical Subject Headings::Named Groups::Persons::Age Groups::AdultMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::Genetic Structures::Genome::Genome Components::Genes::AllelesMedical Subject Headings::Named Groups::Persons::Age Groups::ChildMedical Subject Headings::Named Groups::Persons::Age Groups::Child::Child, PreschoolMedical Subject Headings::Check Tags::FemaleMedical Subject Headings::Diseases::Congenital, Hereditary, and Neonatal Diseases and Abnormalities::Congenital Abnormalities::Chromosome Disorders::Sex Chromosome Disorders::Fragile X SyndromeMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::Gene FrequencyMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Investigative Techniques::Genetic Techniques::Genetic TestingMedical Subject Headings::Organisms::Eukaryota::Animals::Chordata::Vertebrates::Mammals::Primates::Haplorhini::Catarrhini::Hominidae::HumansMedical Subject Headings::Named Groups::Persons::Age Groups::InfantMedical Subject Headings::Named Groups::Persons::Age Groups::Infant::Infant, NewbornMedical Subject Headings::Check Tags::MaleMedical Subject Headings::Named Groups::Persons::Age Groups::Adult::Middle AgedMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Investigative Techniques::Epidemiologic Methods::Data Collection::RegistriesMedical Subject Headings::Geographicals::Geographic Locations::Europe::SpainMedical Subject Headings::Named Groups::Persons::Age Groups::Adolescentresearch article24987673open access10.1155/2014/1957932314-6141PMC4058505