{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T08:21:55Z","timestamp":1790238115883,"version":"4.1.0"},"reference-count":24,"publisher":"BMJ","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Med Genet"],"published-print":{"date-parts":[[1997,1]]},"abstract":"<jats:p>In 1986, a population study of school children in the city of Coventry gave an overall prevalence in males and females for fragile X syndrome of 1\/952. The 29 children diagnosed as having fragile X syndrome in this study have been re-evaluated with molecular diagnostic techniques. Eighteen of the original 29 children have been found not to have the expansion of the FMR1 gene associated with fragile X syndrome. Revised prevalence figures have been calculated giving rise to an overall prevalence figure of 1\/2720 (range 1\/2198-1\/3089). If the four children lost to follow up are also assumed not to have the fragile X syndrome, the revised prevalence figure was 1\/5714 (range 1\/4762-1\/6349). Clinical review of boys with severe mental retardation from this and a subsidiary study show that the clinical features of head circumference greater than the 50th centile, testicular volume greater than the 50th centile, and IQ between 35 and 70 remain helpful in distinguishing boys with fragile X syndrome from those who have non-specific mental retardation.<\/jats:p>","DOI":"10.1136\/jmg.34.1.1","type":"journal-article","created":{"date-parts":[[2008,11,10]],"date-time":"2008-11-10T15:37:21Z","timestamp":1226331441000},"page":"1-5","source":"Crossref","is-referenced-by-count":60,"title":["Fragile X syndrome is less common than previously estimated."],"prefix":"10.1136","volume":"34","author":[{"given":"J E","family":"Morton","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S","family":"Bundey","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"T P","family":"Webb","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"F","family":"MacDonald","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P M","family":"Rindl","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S","family":"Bullock","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[1997,1,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"396","DOI":"10.1136\/jmg.23.5.396","article-title":"The frequency of the fragile X chromosome among schoolchildren in Coventry","volume":"23","author":"Webb, T.P.; Bundey, S.; Thake, A.; Todd, J.","year":"1986","unstructured":"Webb TP, Bundey S, Thake A, Todd J. The frequency of the fragile X chromosome among schoolchildren in Coventry. J Med Genet 1986;23:396-9.","journal-title":"J Med Genet"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1111\/j.1399-0004.1990.tb03498.x","article-title":"The common fragile site in band q27 of the human X chromosome is not coincident with the fragile X","volume":"37","author":"Sutherland, G.R.; Baker, E.","year":"1990","unstructured":"Sutherland GR, Baker E. The common fragile site in band q27 of the human X chromosome is not coincident with the fragile X. Clin Genet 1990;37:167-72.","journal-title":"Clin Genet"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1097","DOI":"10.1126\/science.252.5009.1097","article-title":"Instability of a 550- base pair DNA segment and abnormal methylation in fragile X syndrome","volume":"252","author":"Oberle, I.; Rousseau, F.; Heitz, D.","year":"1991","unstructured":"Oberle I, Rousseau F, Heitz D, et al. Instability of a 550- base pair DNA segment and abnormal methylation in fragile X syndrome. Science 1991;252:1097-102.","journal-title":"Science"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1179","DOI":"10.1126\/science.252.5009.1179","article-title":"Fragile X genotype characterised by an unstable region of DNA","volume":"252","author":"Yu, S.; Pritchard, M.; Kremer, E.","year":"1991","unstructured":"Yu S, Pritchard M, Kremer E, et al. Fragile X genotype characterised by an unstable region of DNA. Science 1991; 252:1179-81.","journal-title":"Science"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"905","DOI":"10.1016\/0092-8674(91)90397-H","article-title":"Identification of a gene (FMR-1) containing a CGG repeat coincident with a breakpoint cluster region exhibiting length variation in fragile X syndrome","volume":"65","author":"Verkerk, A.J.M.H.; Pieretti, M.; Sutcliffe, J.S.","year":"1991","unstructured":"Verkerk AJMH, Pieretti M, Sutcliffe JS, et al. 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Clinical screening score for the fragile X (Martin-Bell) syndrome. Am JMed Genet 1991;38:256-9.","journal-title":"Am JMed Genet"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1001","DOI":"10.1136\/adc.60.11.1001","article-title":"Is it possible to make a clinical diagnosis of the fragile X syndrome in a boy?","volume":"60","author":"Thake, A.; Todd, J.; Bundey, S.; Webb, T.","year":"1985","unstructured":"Thake A, Todd J, Bundey S, Webb T. Is it possible to make a clinical diagnosis of the fragile X syndrome in a boy? Arch Dis Child 1985;60:1001-7.","journal-title":"Arch Dis Child"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1136\/jmg.30.2.97","article-title":"Identification of the FRAXE fragile site in two families ascertained for X linked mental retardation","volume":"30","author":"Flynn, G.A.; Hirst, M.C.; Knight, S.J.L.","year":"1993","unstructured":"Flynn GA, Hirst MC, Knight SJL, et al. 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