ß 2008 Wiley-Liss, Inc. American Journal of Medical Genetics Part A 146A:2611–2616 (2008) Genetic Counseling in Robertsonian Translocations der(13;14): Frequencies of Reproductive Outcomes and Infertility in 101 Pedigrees Hartmut Engels, 1 * Thomas Eggermann, 2 Almut Caliebe, 3 Anna Jelska, 4 Regine Schubert, 1,5 Herdit M. Schu ¨ler, 2 Barbara Panasiuk, 3 Jacek Zaremba, 6 Anna Latos-Bielen ´ ska, 7 Lucjusz Jakubowski, 8 Klaus P. Zerres, 2 Gesa Schwanitz, 1 and Alina T. Midro 3 1 Institute of Human Genetics, Bonn, Germany 2 Institute of Human Genetics, University of Technology, Aachen, Germany 3 Institute of Human Genetics, Kiel, Germany 4 Department of Clinical Genetics, Medical University, Bialystok, Poland 5 Clinic for Human Genetics Meschede & Schubert, Cologne, Germany 6 Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland 7 Department of Medical Genetics, University of Medical Sciences, Poznan ´, Poland 8 Department of Medical Genetics Institute of Polish Mother, Lo ´dz ´, Poland Received 24 August 2007; Accepted 30 June 2008 Robertsonian translocations 13/14 are the most common chromosome rearrangements in humans. However, most studies aimed at determining risk figures are more than 20 years old. Their results are often contradictory regarding important topics in genetic counseling such as infertility and unfavorable pregnancy outcomes. Here, we present a study on a sample of 101 previously unreported pedigrees of der(13;14)(q10;q10). In order to minimize problems of partial ascertainment, we included families with a wide range of reasons of ascertainment such as birth of a child with congenital anomalies, prenatal diagnosis due to maternal age, fertility problems and recurrent pregnancy loss. No evidence of increased infertility rates of female and male carriers was found. The detected miscarriage frequency of female carriers was higher than previously reported (27.6  4.0% of all spontaneous pregnancies). This may be explained by an over-correction of earlier studies, which excluded all unkaryotyped miscarriages. In three out of 42 amniocenteses, translocation trisomies 13 were diagnosed (7.1  4.0% of all amniocenteses). The frequency of stillbirths was 3.3  1.6% for female carriers and 1.4  1.4% for male carriers. A low risk for the live birth of translocation trisomy 13 children was confirmed since no live born children with trisomy 13 or Pa ¨tau syndrome were detected in the ascertainment-corrected sample. ß 2008 Wiley-Liss, Inc. Key words: frequency of unbalanced progeny; der(13 ;14); infertility; genetic counseling; miscarriage; pregnancy out- come; Robertsonian translocation How to cite this article: Engels H, Eggermann T, Caliebe A, Jelska A, Schubert R, Schu ¨ ler HM, Panasiuk B, Zaremba J, Latos-Bielen ´ ska A, Jakubowski L, Zerres KP, Schwanitz G, Midro AT. 2008. Genetic counseling in Robertsonian translocations der(13;14): Frequencies of reproductive outcomes and infertility in 101 pedigrees. Am J Med Genet Part A 146A:2611 – 2616. INTRODUCTION Robertsonian translocations are the most common balanced chromosome rearrangements in humans with a frequency of roughly 1 in 1,000 in newborn surveys [Nielsen and Wohlert, 1991]. Robertsonian translocations of chromosomes 13 and 14 constitute nearly three quarters of all Robertsonian trans- locations, making it the most common chromosome rearrangement in humans with a prevalence of about 1 in 1,300 [Gardner and Sutherland, 2004]. Carriers of der(13;14)(q10;q10) are usually phenotypically nor- mal but are at risk to produce unbalanced gametes. The frequency of der(13;14) carriers in male infertility cohorts is about 10 times higher than in newborn surveys [Tharapel et al., 1985]. Unfavorable Gesa Schwanitz, Alina T. Midro contributed equally to this work. Grant sponsor: BMBF; Grant number: POL03/025; Grant sponsor: KBN; Grant numbers: 5253, 2 PO5A 089 27; Grant sponsor: AMB; Grant number: 4-06 760. *Correspondence to: Dr. Hartmut Engels, Institute of Human Genetics, University of Bonn, Wilhelmstrasse 31, D-53111 Bonn, Germany. E-mail: hartmut.engels@ukb.uni-bonn.de Published online 16 September 2008 in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/ajmg.a.32500