title: Cytogenetic versus DNA diagnosis in routine referrals for fragile X syndrome.
abstract: The molecular cloning of the gene that causes the fragile X syndrome, and the demonstration that the causative mutation is an expansion of an unstable trinucleotide repeat, suggests that cytogenetic testing could be replaced by a molecular test. We compared the two methods in 525 routine referrals. 12 cases were positive in both tests. 1 case that had a negative DNA test for the fragile site at Xq27.3 (FRAXA), but a positive cytogenetic result, was shown to be caused by a mutation at the FRAXE locus on chromosome Xq28. DNA analysis is a sensitive, reliable, and cost-effective diagnostic alternative.
authors.affiliation: Division of Medical and Molecular Genetics, United Medical Schools, Guy's Hospital, London, UK.
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: E
authors.initials: E
authors.lastname: Green
authors.forename: A
authors.initials: A
authors.lastname: Barnicoat
authors.forename: D
authors.initials: D
authors.lastname: Garrett
authors.forename: M
authors.initials: M
authors.lastname: Mullarkey
authors.forename: M
authors.initials: M
authors.lastname: Bobrow
authors.forename: C G
authors.initials: CG
authors.lastname: Mathew
mesh_terms: D000483:Alleles; D002648:Child; D002675:Child, Preschool; D043283:Chromosome Fragile Sites; D002873:Chromosome Fragility; D003582:Cytogenetics; D004247:DNA / Q000032:analysis*; D005260:Female; D005600:Fragile X Syndrome / Q000175:diagnosis* / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics; D012017:Referral and Consultation; D014960:X Chromosome
chemical_list: D004247:DNA