[Usefulness of CGH-array and SNP-array for the etiological diagnosis of premature ovarian insufficiency]

Premature ovarian insufficiency (POI) defined by the cessation of ovarian function before the age of 40 years and the increase of gonadotropins (> 25 UI/l) occurs in approximately 1-5% of women. Different mechanisms are responsible for POI: chemotherapy, radiotherapy, environmental factors or genetic causes but most frequently no cause is identified. In order to determine the etiology of POI, cytogenetic analyses such as karyotype are performed. The karyotype allows to identify abnormalities of the number of chromosomes as well as abnormalities of the structure such as translocations, deletions or insertions of a size greater than 5-10 Mb… Turner syndrome is the most frequent genetic cause of POI and deletions of the long arm of the X chromosome are other causes of POI identified by the karyotype. However, the resolution of the karyotype is low and other cytogenetic techniques were developed such as all genome microarray analysis. This technique includes CGH-array and SNP-array and allows to identify gain or loss of chromosomal material as small as 10 kb but not the balanced structural rearrangements. Different studies using microarray analysis in cohorts of patients presenting with POI identify candidate genes responsible for POI. Furthermore, they allowed to identify a recurrent microdeletion, which includes the CPEB1 gene, located in 15q25.2 in about 1.5% of patients with POI.