Clin Genet 2010: 78: 373 – 376 Printed in Singapore. All rights reserved  2010 John Wiley & Sons A/S CLINICAL GENETICS doi: 10.1111/j.1399-0004.2010.01404.x Short Report The contribution of founder mutations in BRCA1 to breast and ovarian cancer in Lithuania Elsakov P, Kurtinaitis J, Petraitis S, Ostapenko V, Razumas M, Razumas T, Meskauskas R, Petrulis K, Luksite A, Lubi´ nski J, G´ orski B, Narod SA, Gronwald J. The contribution of founder mutations in BRCA1 to breast and ovarian cancer in Lithuania. Clin Genet 2010: 78: 373–376.  John Wiley & Sons A/S, 2010 We evaluated the prevalence of BRCA1 founder mutations in unselected cases of breast, ovarian and colon cancer from Lithuania. We identified a founder mutation (4153delA, 5382insC or C61G) in 6% of 235 unselected cases of breast cancer and in 19% of 43 unselected cases of ovarian cancer. Only one patient with a mutation was identified among 178 cases of colon cancer. No mutation was identified among 422 newborn controls. This data indicates that the genetic burden of breast and ovarian cancer attributable to BRCA1 mutations in Lithuania is very high and supports the recommendation that all cases of breast and ovarian cancer in Lithuania be offered genetic testing. P Elsakov a , J Kurtinaitis a , S Petraitis a , V Ostapenko a , M Razumas b , T Razumas a , R Meskauskas c , K Petrulis a , A Luksite a , J Lubi ´ nski d , BG´ orski d , SA Narod e and J Gronwald d a Institute of Oncology, Vilnius University, Vilnius, Lithuania, b Vilnius Maternity Hospital, Vilnius, Lithuania, c National Center of Pathology, Vilnius, Lithuania, d IHCC, Pomeranian Medical University, Szczecin, Poland, and e Womens College Research Institute, Toronto, Ontario, Canada Key words: BRCA1 founder mutation – breast cancer – colorectal cancer – frequency – ovarian cancer – unselected patients Corresponding author: Steven A Narod, Womens College Research Institute, Toronto, Ontario, Canada. Tel.: +1 416- 351- 3765; fax: +1 416- 351- 3767; e-mail: steven.narod@wchospital.ca Received 7 October 2009, revised and accepted for publication 9 February 2010 The Baltic states comprise three countries (Lithua- nia, Latvia and Estonia) with different languages and ethnic compositions. In two previous stud- ies of families from Latvia with the hereditary breast-ovarian cancer syndrome, three recurrent mutations in BRCA1 were identified (4153delA, 5382insC and C61G) (1, 2). Each of these three mutations is also a founder mutation in the Polish population (3). These three mutations account for approximately 80–90% of all detectable BRCA1 and BRCA2 gene mutations in Latvia and in Poland (1, 2, 4). The contribution of BRCA1 mutations to the burden of colon cancer in Eastern Europe has not been well studied. Previous studies of the Lithuanian population have concentrated on breast-ovarian cancer fam- ilies. Gronwald et al. found a founder mutation in 9 of 13 familial breast/ovarian cancer families (5). Janaviˇ cius et al. studied 28 Lithuanian patients who were referred for familial breast/ovarian can- cer (6); in total, eight mutations were found; a founder mutation was found in seven families. In these two studies, families were selected for fam- ily history; the contribution of these three founder 373