title: Rapid determination of trisomy 18 parental origin using fluorescent PCR and small tandem repeat markers: case reports.
abstract: Trisomy 18 is the second most common genetic defect after trisomy 21, almost 90% of which are due to additional chromosome from the mother. The parental origin of the additional chromosome can, if required, be determined by two methods: karyotyping, which takes several weeks; or, more recently, by polymerase chain reaction (PCR) which is often problematic. Fluorescent PCR of small tandem repeats (STRs) can determine the parental origin in the majority of cases within 5 h. Although the incidence of paternal origin is known for both trisomy 21 and trisomy 18, this technique can rapidly determine the parental origin in cases where there is insufficient samples to perform conventional tests. Determining parental origin by these methods may also have clinical significance in the diagnosis of chromosomal translocations or in the diagnosis of genetic disease using linkage analysis.
authors.affiliation: Molecular Oncology, Institute of Pathology, University of Leeds, UK. I.Findlay@leeds.ac.uk
authors.forename: I
authors.initials: I
authors.lastname: Findlay
authors.forename: T
authors.initials: T
authors.lastname: Tóth
authors.forename: P
authors.initials: P
authors.lastname: Matthews
authors.forename: T
authors.initials: T
authors.lastname: Marton
authors.forename: P
authors.initials: P
authors.lastname: Quirke
authors.forename: Z
authors.initials: Z
authors.lastname: Papp
mesh_terms: D002887:Chromosomes, Human, Pair 18; D005260:Female; D005452:Fluoresceins; D005456:Fluorescent Dyes; D005819:Genetic Markers; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D011296:Prenatal Diagnosis; D012091:Repetitive Sequences, Nucleic Acid; D013997:Time Factors; D014314:Trisomy
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; D005819:Genetic Markers; C045132:4-carboxyfluorescein