title: Fragile X syndrome with extra microchromosome.
abstract: A mentally retarded male with Martin-Bell syndrome, who has an extra microchromosome and is fra X negative in cytogenetic study is reported. Because of its small size, the origin of the microchromosome could not be determined. Two other affected males in this family (a cousin and a nephew of the proband) were fragile X positive, 24% and 26%, respectively. Cytogenetic studies and DNA analysis with the probe St B 12.3 were performed on several members of the family. The proband and the two other affected males showed a similar full mutation on the molecular study. This study emphasizes the importance of molecular analysis in the diagnosis of fragile X syndrome, particularly when cytogenetic studies demonstrate fra X negative in individuals in families likely to have X-linked mental retardation.
authors.affiliation: Sección de Genética Médica, Hospital La Paz, Madrid, Spain.
authors.forename: I
authors.initials: I
authors.lastname: López-Pajares
authors.forename: A
authors.initials: A
authors.lastname: Delicado
authors.forename: I
authors.initials: I
authors.lastname: Pascual-Castroviejo
authors.forename: V
authors.initials: V
authors.lastname: López-Martin
authors.forename: F
authors.initials: F
authors.lastname: Moreno
authors.forename: J A
authors.initials: JA
authors.lastname: Garcia-Marcos
mesh_terms: D000328:Adult; D000818:Animals; D015139:Blotting, Southern; D002871:Chromosome Banding; D002873:Chromosome Fragility; D006224:Cricetinae; D003582:Cytogenetics; D015342:DNA Probes; D005600:Fragile X Syndrome / Q000235:genetics*; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics; D007621:Karyotyping; D008297:Male; D010375:Pedigree; D014960:X Chromosome
chemical_list: D015342:DNA Probes