BRCA1 testing in breast and/or ovarian cancer families from northeastern France identifies two common mutations with a founder effect.
OBJECTIVE
The purpose of this study was to determine whether two mutations detected frequently in a population of breast and/or ovarian cancer families originating from the northeastern part of France could be due to a founder effect.


METHODS
83 index cases of families ascertained to have a familial breast and/or ovarian cancer history, were screened for mutations in all coding exons of the BRCA1 gene, using combined DGGE and direct sequencing. For haplotype analysis, six polymorphic markers were used for allelotyping of mutation carriers and non carriers from nine families with 3600del11 mutation and four families with G1710X mutation.


RESULTS
Of 83 index cases, 27 (32%) had 14 different BRCA1 mutations, one of which (G1710X), had not been reported in other populations. Two mutations were particularly common: 3600del11 in exon 11 accounted for 37% and the nonsense mutation G1710X in exon 18 for 15% of all mutations. We identified a common haplotype for each mutation suggesting a common founder for each recurrent mutation. No specific phenotype could be assigned to any of the common mutations.


CONCLUSIONS
These data demonstrate geographical clustering and suggest a founder effect for particular BRCA1 mutations, which identification will facilitate carrier detection in French families with breast cancer and breast and/or ovarian cancer.
Muller
Danièle
D
Unitè de Génétique Oncologique and Laboratoire de Biologie Tumorale, Centre Régional de Lutte Contre le Cancer Paul Strauss, 67065 Strasbourg Cedex, France. btumorale@strasbourg.fnclcc.fr
Bonaiti-Pellié
Catherine
C
Abecassis
Joseph
J
Stoppa-Lyonnet
Dominique
D
Fricker
Jean-Pierre
JP
D000328:Adult; D019313:BRCA1 Protein / Q000235:genetics*; D001943:Breast Neoplasms / Q000453:epidemiology / Q000235:genetics*; D016000:Cluster Analysis; D015331:Cohort Studies; D005260:Female; D005602:France / Q000453:epidemiology; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D005838:Genotype; D018095:Germ-Line Mutation; D006239:Haplotypes; D006579:Heterozygote; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000453:epidemiology / Q000235:genetics*; D010375:Pedigree
D019313:BRCA1 Protein