title: Carrier and prenatal diagnostic strategy and newly identified mutations in Hungarian haemophilia A and B families.
abstract: Deficiencies of blood coagulation factors VIII and IX (haemophilia A and haemophilia B) represent the most common inherited bleeding disorders with a wide range of causative mutations. Carrier and prenatal diagnostics are preferably performed by direct mutation detection; however, in certain situations, indirect family studies may also be useful. We aimed to utilize a combination of direct and indirect techniques for carrier and prenatal diagnostics in both haemophilias in a single national centre. Two hundred and eleven haemophilia A families were investigated by screening for inversions of introns 1 and 22, and by family studies using polymorphic markers. Twenty-eight haemophilia A and 39 haemophilia B families were investigated by Sanger-sequencing of the coding regions. Among severe haemophilia A families, frequencies of intron 22 and 1 inversions were 82 out of 145 (57%) and two out of 145 (1.4%). Sequencing of the entire coding region of the respective factor gene was performed and 12 (haemophilia A) and 5 (haemophilia B) previously unpublished disease-causing mutations were identified. For genetic markers used for haemophilia A indirect family testing, heterozygosity rates varied between 137 out of 327 [42% intragenic BclI restriction fragment length polymorphism (RFLP], 168 out of 254 (66% intragenic F8Civs13CA) and 202 out of 261 (77% extragenic DXS15CA) with a combined rate of 92% (intragenic markers) and 97% (all three markers). For male fetuses, prenatal diagnostics was provided to 43 haemophilia A families (n = 22 with direct mutation detection and n = 21 by indirect family testing) and to three haemophilia B families. The combination of direct and indirect molecular genetics approaches is a successful and cost-effective approach to provide carrier and prenatal diagnostics and risk assessment for inhibitor formation.
authors.affiliation: aLaboratory of Molecular Diagnostics, Hungarian National Blood Transfusion Service, Budapest bHungarian National Blood Transfusion Service, Szombathely cHospital of Mohács, Pediatric Department, Mohács dHeim Pál Children's Hospital eNational Haemophilia Center and Haemostasis Department, State Health Centre, Budapest, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Bors
authors.forename: Hajnalka
authors.initials: H
authors.lastname: Andrikovics
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Illés
authors.forename: Rita
authors.initials: R
authors.lastname: Jáger
authors.forename: Mária
authors.initials: M
authors.lastname: Kardos
authors.forename: Anikó
authors.initials: A
authors.lastname: Marosi
authors.forename: László
authors.initials: L
authors.lastname: Nemes
authors.forename: Attila
authors.initials: A
authors.lastname: Tordai
mesh_terms: D015331:Cohort Studies; D005260:Female; D006580:Genetic Carrier Screening; D006467:Hemophilia A / Q000175:diagnosis / Q000235:genetics*; D002836:Hemophilia B / Q000175:diagnosis / Q000235:genetics*; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*