Next-generation sequencing refines the genetic architecture of Greek GnRH-deficient patients

Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) is a rare disease with a wide spectrum of reproductive and non-reproductive clinical characteristics. Apart from the phenotypic heterogeneity, IGD is also highly genetically heterogeneous with >35 genes implicated in the disease. Despite this genetic heterogeneity, genetic enrichment in specific subpopulations has been described. We have previously described low prevalence of genetic variation in the Greek IGD cohort discovered with utilization of Sanger sequencing in 14 known IGD genes. Here, we describe the expansion of genetic screening in the largest IGD Greek cohort that has ever been studied with the usage of whole-exome sequencing, searching for rare sequencing variants (RSVs) in 37 known IGD genes. Even though Sanger sequencing detected genetic variation in 21/81 IGD patients in 7/14 IGD genes without any evidence of oligogenicity, whole exome sequencing (WES) revealed that 27/87 IGD patients carried a rare genetic change in a total of 15 genes with 4 IGD cases being oligogenic. Our findings suggest that next-generation sequencing (NGS) techniques can discover previously undetected variation, making them the standardized method for screening patients with rare and/or more common disorders.

Unilateral renal agenesis as an early marker for genetic screening in Kallmann syndrome

Isolated GnRH Deficiency (IGD) that is either displayed as Kallmann Syndrome (KS) or normosmic idiopathic hypogonadotropic hypogonadism (nIHH) is a rare Mendelian disorder with wide clinical and genetic variability. Apart from the arrest of pubertal development, IGD is also characterized by a variety of non- reproductive features including unilateral renal agenesis (URA), midline defects, dental & ocular defects and many more. In this analysis we explored the role of unilateral renal agenesis, as a screening tool for detection of genetic changes associated with IGD. We performed detailed genetic screening with Sanger sequencing in 14 genes associated with Isolated GnRH Deficiency as well as screening of intragenic deletions in the gene of anosmin 1-ANOS1 with MLPA. No genetic variation was detected, suggestive of an alternative genetic cause for URA in these normosmic patients, highlighting the necessity of further genetic screening.

Impact of estrogen receptor α gene and oxytocin receptor gene polymorphisms on female sexuality

Over the past decades, research attention has increasingly been paid to the neurobiological component of sexual behavior. The aim of the present study was to investigate the correlation of estrogen receptor α (ERA) gene polymorphism (rs2234693-PvuII) (T→C substitution) and oxytocin receptor gene polymorphism (rs53576) (G→A substitution) with sexuality parameters of young, healthy women. One hundred thirty-three Greek heterosexual women, students in higher education institutions, 20-25 years of age, sexually active, with normal menstrual cycles (28-35 days), were recruited in the study. Exclusion criteria were chronic and/or major psychiatric diseases, use of oral contraceptive pills (OCs), polycystic ovary syndrome (PCOS), thyroid diseases as well as drugs that are implicated in hypothalamus-pituitary-gonadal axis. T allele (wildtype) of rs2234693 (PvuII) polymorphism of ERA gene was correlated with increased levels of arousal and lubrication, whereas A allele (polymorphic) of rs53576 (OXTR) polymorphism was correlated with increased arousal levels. The simultaneous presence of both T allele of rs2234693 (PvuII) and A allele of rs53576 (OXTR) polymorphisms (T + A group) was correlated with increased arousal, orgasm levels as well as female sexual function index full score. To our knowledge, this is the first study to investigate the interaction between ERA and OXTR with regard to sexual function in women. Female sexuality is a complex behavioral trait that encompasses both biological and psychological components. It seems that variability in female sexual response stems from genetic variability that characterizes endocrine, neurotransmitter and central nervous system influences.

Gene variants associated with age at menopause are also associated with polycystic ovary syndrome, gonadotrophins and ovarian volume

STUDY QUESTION

Is there a relationship between the genetic risk for polycystic ovary syndrome (PCOS) and genetic variants that influence timing of menopause?

SUMMARY ANSWER

The genetic risk score, which sums the contribution of variants at all menopause loci, was associated with PCOS.

WHAT IS ALREADY KNOWN

Ovarian parameters and anti-Mullerian hormone levels suggest that women with PCOS should have a later age at menopause.

STUDY DESIGN, SIZE, DURATION

The study was a case-control examination of genetic variants associated with age at menopause in a discovery cohort of women with PCOS (n = 485) and controls (n = 407) from Boston recruited from 2003 to 2012. Replication was performed in women from Greece (cases, n = 884 and controls, n = 311).

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

PCOS was defined by the National Institutes of Health criteria in Boston and Greece (n = 783), with additional subjects fulfilling the Rotterdam criteria (hyperandrogenism, polycystic ovary morphology and regular menses) in Greece (n = 101). Controls in Boston and Greece had regular menstrual cycles and no hyperandrogenism. Allele frequencies for variants previously associated with age at menopause were examined in PCOS cases and controls, along with the relationship to quantitative traits.

MAIN RESULTS AND ROLE OF CHANCE

The variant rs11668344-G was associated with decreased risk of PCOS (odds ratio: 0.77 [0.59-0.93]; P = 0.004). There was a strong relationship between the late menopause allele rs12294104-T and increased LH levels (β ± SE; 0.26 ± 0.06; P = 5.2 × 10(-5)) and the LH:FSH ratio (0.28 ± 0.06; P = 2.7 × 10(-6)). The minor allele at rs10852344-T was associated with smaller ovarian volume (-0.16 ± 0.05; P = 0.0012). A genetic risk score calculated from 16 independent variants associated with age at menopause was also associated with PCOS (P < 0.02), LH and the LH:FSH ratio (both P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

The variant rs11668344 was not associated with PCOS in the Greek cohort, but results exhibited the same direction of effect as the Boston cohort. However, it is possible that the individual association was a false positive in the Boston cohort.

WIDER IMPLICATIONS OF THE FINDINGS

The study demonstrates that gene variants known to influence age at menopause are also associated with risk for PCOS. Further, our data suggest that the relationship between age at menopause and PCOS may be explained, at least in part, by effects on LH levels and follicle number. The data point to opposing influences of the genetic variants on both menopausal age and PCOS.

STUDY FUNDING/COMPETING INTERESTS

The project was supported by award number R01HD065029 from the Eunice Kennedy Shriver National Institute of Child Health & Human Development, award number 1 UL1 RR025758, Harvard Clinical and Translational Science Center, from the National Center for Research Resources and award 1-10-CT-57 from the American Diabetes Association. C.K.W. is a consultant for Takeda Pharmaceuticals.

TRIAL REGISTRATION NUMBER

NCT00166569.

Han Chinese polycystic ovary syndrome risk variants in women of European ancestry: relationship to FSH levels and glucose tolerance

STUDY QUESTION

Are PCOS risk variants identified in women of Han Chinese ethnicity also associated with risk of PCOS or the phenotypic features of PCOS in European women?

SUMMARY ANSWER

One variant, rs2268361-T, in the intron of FSHR was associated with PCOS and lower FSH levels, while another variant rs705702-G near the RAB5B and SUOX genes was associated with insulin and glucose levels after oral glucose testing in women with PCOS of European ethnicity.

WHAT IS KNOWN ALREADY

Three of the eleven variants associated with PCOS in the Han Chinese genome-wide association studies were also associated with PCOS in at least one European population when corrected for multiple testing (DENND1A, THADA and YAP1). However, additional replication is needed to establish the importance of these variants in European women and to determine the relationship to PCOS phenotypic traits.

STUDY DESIGN, SIZE, DURATION

The study was a case-control examination in a discovery cohort of women with PCOS (n = 485) and controls (n = 407) from Boston (Boston 1). Replication was performed in women from Greece (cases n = 884 and controls n = 311) and an additional cohort from Boston (Boston electronic medical record (EMR); n = 350 cases and n = 1258 controls).

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Women had PCOS defined by the National Institutes of Health criteria in Boston 1 and Greece (n = 783), with additional subjects fulfilling the Rotterdam criteria (hyperandrogenism, polycystic ovary morphology and regular menses) in Greece (n = 101). Controls in Boston and Greece had regular menstrual cycles and no hyperandrogenism. The second cohort from Boston was defined using the EMR and natural language processing. Allele frequencies for variants associated with PCOS in Han Chinese women were examined in PCOS cases and controls, along with the relationship to quantitative traits.

MAIN RESULTS AND THE ROLE OF CHANCE

A variant rs2268361-T in an intron of FSHR was associated with PCOS (0.84 [0.76-0.93], OR [95% CI]; P = 0.002). The rs2268361-T was associated with lower FSH levels (-0.15 ± 0.05; P = 0.0029). A variant rs705702-G near RAB5B and SUOX was associated with insulin (-0.16 ± 0.05, P = 0.0029) and glucose levels (-0.20 ± 0.05, P = 0.0002) 120 min after an oral glucose test.

LIMITATIONS, REASONS FOR CAUTION

The study was large and contained replication cohorts, but was limited by a small number of controls in the Greek cohort and a small number of cases in the second Boston cohort. The second Boston group was identified using electronic medical record review, but was validated for the cardinal features of PCOS.

WIDER IMPLICATIONS OF THE FINDINGS

This study demonstrates a cross-ethnic PCOS risk locus in FSHR in women of European ancestry with PCOS. The variant may influence FSH receptor responsiveness as suggested by the associated change in FSH levels. The relationship between a variant near RAB5B and SUOX and glucose stimulated insulin and glucose levels suggests an influence of one of these genes on glucose tolerance, but the absence of a relationship with PCOS points to potential differences in the international PCOS patient populations.

STUDY FUNDING/COMPETING INTERESTS

The project was supported by Award Number R01HD065029 from the Eunice Kennedy Shriver National Institute Of Child Health & Human Development, Award Number 1 UL1 RR025758, Harvard Clinical and Translational Science Center, from the National Center for Research Resources, award 1-10-CT-57 from the American Diabetes Association and the Partners Healthcare Center for Personalized Genetics Project Grant. C.K.W. is a consultant for Takeda Pharmaceuticals.

TRIAL REGISTRATION NUMBER

NCT00166569.