Identification and in vitro characterization of follicle stimulating hormone (FSH) receptor variants associated with abnormal ovarian response to FSH.
BACKGROUND
FSH mediates cyclic follicle growth and development and is widely used for controlled ovarian stimulation in women undergoing infertility treatment. The ovarian response of women to FSH is variable, ranging from poor response to ovarian hyperstimulation.


OBJECTIVE
We investigated whether genetic alterations of the FSH receptor (FSHR) contribute to this variability.


METHODS
Our approach was to study women undergoing treatment with in vitro fertilization falling into the edges of the normal distribution of ovarian response to FSH, with respect to age.


METHODS
We conducted the study at the Yale Fertility Clinic.


METHODS
We extracted RNA from cumulus cells surrounding the oocytes of women undergoing in vitro fertilization and analyzed the FSHR mRNA by RT-PCR and sequencing.


RESULTS
We identified four abnormal FSHR splicing products (three exon deletions and one intron insertion) in the FSHR mRNA in 37% (13 of 35) of women tested. All alterations affected the extracellular ligand-binding portion of the receptor without causing a frameshift. When transfected in HEK293T cells, all four splicing variants showed markedly decreased cAMP activation compared to controls. Untransfected cells showed no response to FSH, whereas all the cell lines showed normal cAMP activation when treated with forskolin, a nonreceptor-mediated cAMP stimulant. None of the normal or mutant forms showed any response to LH or TSH.


CONCLUSIONS
Our findings strongly indicate FSHR variants as being an intrinsic genetic cause of some forms of infertility and identify a need for functional characterization of these variants and the investigation of more individualized ovarian stimulation protocols.
Gerasimova
Tsilya
T
Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, 333 Cedar Street, Room FMB 329J, New Haven, Connecticut 06520, USA. maria.lalioti@yale.edu
Thanasoula
Maria N
MN
Zattas
Dimitrios
D
Seli
Emre
E
Sakkas
Denny
D
Lalioti
Maria D
MD
D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000096:biosynthesis; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006801:Humans; D007986:Luteinizing Hormone / Q000494:pharmacology; D008875:Middle Aged; D010053:Ovary / Q000187:drug effects*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000032:analysis; D011962:Receptors, FSH / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger; D011962:Receptors, FSH; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D000242:Cyclic AMP