title: False non-paternity in a family for prenatal diagnosis of beta-thalassaemia.
abstract: Initial screening for the common beta-thalassaemia mutations with allele-specific oligonucleotide probes in an at-risk family suggested non-paternity. Subsequent DNA fingerprinting of the members proved otherwise. The mother had a codon 41/42 frameshift mutation and the father's defect, determined by direct sequencing of PCR-amplified beta gene, was a codon 43 nonsense mutation. In the affected children, the close proximity of these two defects resulted in the absence of a hybridization signal to the normal probe in that region and a wrong assumption of homozygosity for the codon 41/42 mutation. The non-reactivity of the father's amplified DNA to the codon 41/42 thalassaemic probe accounted for the initial wrong conclusion of non-paternity. Since prior screening for beta-thalassaemia mutations is done in all prenatal diagnosis programmes and concomitant inheritance of these two defects is relatively common in the Chinese, this 'artefact' of false non-paternity is worth noting.
authors.affiliation: University Department of Medicine, Queen Mary Hospital, Hong Kong.
authors.forename: V
authors.initials: V
authors.lastname: Chan
authors.forename: T P
authors.initials: TP
authors.lastname: Chan
authors.forename: K
authors.initials: K
authors.lastname: Lau
authors.forename: D
authors.initials: D
authors.lastname: Todd
authors.forename: T K
authors.initials: TK
authors.lastname: Chan
mesh_terms: D000328:Adult; D000649:Amniocentesis; D003062:Codon / Q000235:genetics; D016172:DNA Fingerprinting; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000235:genetics; D016368:Frameshift Mutation; D006801:Humans; D008297:Male; D009693:Nucleic Acid Hybridization; D010334:Paternity; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011247:Pregnancy; D017086:beta-Thalassemia / Q000175:diagnosis* / Q000235:genetics
chemical_list: D003062:Codon