Background: Primary ovarian failure (POF) is a major cause of female infertility. POF is characterized by amenorrhea, hypo-estrogenism and elevated gonadotrophin levels. In POF disorder, several genetic alterations have been described, however in most of the patients the etiology of this disorder remains unknown.
Objective and hypotheses: To identify new genes implicated in the development of POF using Next-Generation Sequencing (NGS).
Method: We studied seven familial cases (14 affected women) all of them with primary amenorrhea. DNA of two affected daughters and their sister, who parents are second cousins, was analyzed using Whole-Exome sequencing. Exons and splice sites were captured with the Agilent SureSelectXT Human Exon V5 Kit, and 2×100 bp paired-end WES was performed on an Illumina HiSDefault 2500. The mean coverage of the captured regions was > 100x in all samples. The raw data was aligned to the reference genome (hg19 assembly) with BWA. Variant calling was performed with Freebayes and annotated with ANNOVAR. Sanger Sequencing was used to confirm Exome Sequencing variants and to evaluate 235 fertile women controls for putative identified damaging variants.
Results: One novel homozygous frameshift variant (c.88delT:p.F30fs) in RAD51B, the gene encoding DNA Repair Protein RAD51 Homolog B, which is expressed in ovarian tissue, was identified in two affected women using Exome Sequencing. The unaffected sister was heterozygous for this variant. Additionally, the c.88delT:p.F30fs RAD51B variant is not present in 1000 Genomes, ESP6500 and ExAC databases as well as in the 235 fertile Brazilian women used as a normal control.
Conclusion: Our findings indicate a novel homozygous frameshift variant in RAD51B associated with primary ovarian failure in two sisters. These results suggest RAD51B as a new candidate gene in the etiology of primary ovarian failure.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology