Variants in the ACVR1 gene are associated with AMH levels in women with polycystic ovary syndrome.

BACKGROUND: Polycystic ovaries display an increased number of pre-antral and antral follicles compared with normal ovaries, suggesting that early and late follicle development are disturbed. The pathophysiology of this process is poorly understood. Since the transforming growth factor beta family members, anti-Müllerian hormone (AMH) and bone morphogenetic proteins (BMPs), inhibit FSH sensitivity, their signalling may contribute to the aberrant follicle development in these women. Here, we investigated the role of ALK2, a type I receptor for AMH/BMP signalling, in PCOS using a genetic approach. METHODS: Seven single nucleotide polymorphisms in the ACVR1 gene, encoding ALK2, were genotyped in 359 PCOS patients and 30 normo-ovulatory and 3543 population-based control women, and haplotypes were determined. Subsequently, the association of ACVR1 variants with ovarian parameters and hormone levels was investigated. RESULTS: The polymorphisms rs1220134, rs10497189 and rs2033962 and their corresponding haplotypes did not show different frequencies from controls, but were associated with AMH levels in PCOS women (P = 0.001, P = 0.002 and P = 0.007, respectively). Adjustment for follicle number revealed that the association with AMH levels was, in part, independent from follicle number, suggesting that variants in ACVR1 also influence AMH production per follicle. CONCLUSIONS: Genetic variation within ACVR1 is associated with AMH levels and follicle number in PCOS women, suggesting that ALK2 signalling contributes to the disturbed folliculogenesis in PCOS patients.

A functional anti-mullerian hormone gene polymorphism is associated with follicle number and androgen levels in polycystic ovary syndrome patients.

CONTEXT: The common characteristic of polycystic ovary syndrome (PCOS) is a disturbance in the selection of the dominant follicle, resulting in anovulation. In PCOS women, serum anti-Müllerian hormone (AMH) levels are elevated. Because AMH decreases FSH sensitivity in mice, the elevated AMH levels may contribute to the disturbed follicle selection in PCOS women. OBJECTIVE: The objective of the study was to investigate the role of the AMH signaling pathway in the pathophysiology of PCOS using a genetic approach. DESIGN: The association of the AMH Ile(49)Ser (rs10407022) and the AMH type II receptor -482 A>G (rs2002555) polymorphism with PCOS susceptibility and phenotype was studied in a large cohort of PCOS women. SETTING/SUBJECTS: A total of 331 women with PCOS, 32 normoovulatory controls, and 3635 population-based controls were included. MAIN OUTCOME MEASURES: Ovarian parameters, serum AMH, FSH, androgen, and estradiol levels were measured. RESULTS: Genotype and allele frequencies for the AMH Ile(49)Ser and AMH type II receptor -482 A>G polymorphism were similar in PCOS women and controls. However, within the group of PCOS women, carriers of the AMH (49)Ser allele less often had polycystic ovaries (92.7 vs. 99.5%, P = 0.0004), lower follicle numbers (P = 0.03), and lower androgen levels, compared with noncarriers (P = 0.04). In addition, in vitro studies demonstrated that the bioactivity of the AMH (49)Ser protein is diminished, compared with the AMH (49)Ile protein (P < 0.0001). CONCLUSIONS: Genetic variants in the AMH and AMH type II receptor gene do not influence PCOS susceptibility. However, our results suggest that the AMH Ile(49)Ser polymorphism contributes to the severity of the PCOS phenotype.

A polymorphism in the AMH type II receptor gene is associated with age at menopause in interaction with parity.

BACKGROUND: Anti-Müllerian hormone (AMH) inhibits primordial follicle recruitment in the mouse ovary. We hypothesize that in women AMH signaling also regulates the usage of the primordial follicle pool and hence influences the onset of menopause. Since age at menopause has a strong genetic component, we investigated the role of AMH signaling using a candidate gene approach. METHODS: In two large population-based cohorts of Dutch post-menopausal women (n = 2381 and n = 248), we examined the association between two polymorphisms, one in the AMH gene and one in the AMH type II receptor (AMHR2) gene, and natural age at menopause. RESULTS: The AMH Ile(49)Ser polymorphism (rs10407022) was not associated with age at menopause in either cohort. In the Rotterdam cohort, the AMHR2 -482 A > G polymorphism (rs2002555) was associated with age at menopause in interaction with the number of offspring (P = 0.001). Nulliparous women homozygous for the G-allele entered menopause 2.6 years earlier compared with nulliparous women homozygous for the A-allele (P = 0.005). In the LASA cohort, women with the G/G genotype tended to enter menopause 2.8 years earlier compared with the A/A genotype (P = 0.063). CONCLUSIONS: The observed association of the AMHR2 -482 A > G polymorphism with natural age at menopause suggests a role for AMH signaling in the usage of the primordial follicle pool in women.

Anti-Müllerian hormone and anti-Müllerian hormone type II receptor polymorphisms are associated with follicular phase estradiol levels in normo-ovulatory women.

BACKGROUND: In mice, anti-Müllerian hormone (AMH) inhibits primordial follicle recruitment and decreases FSH sensitivity. Little is known about the role of AMH in human ovarian physiology. We hypothesize that in women AMH has a similar role in ovarian function as in mice and investigated this using a genetic approach. METHODS: The association of the AMH Ile(49)Ser and the AMH type II receptor (AMHR2) -482 A > G polymorphisms with menstrual cycle characteristics was studied in a Dutch (n = 32) and a German (n = 21) cohort of normo-ovulatory women. RESULTS: Carriers of the AMH Ser(49) allele had higher serum estradiol (E(2)) levels on menstrual cycle day 3 when compared with non-carriers in the Dutch cohort (P = 0.012) and in the combined Dutch and German cohort (P = 0.03). Carriers of the AMHR2 -482G allele also had higher follicular phase E(2) levels when compared with non-carriers in the Dutch cohort (P = 0.028), the German cohort (P = 0.048) and hence also the combined cohort (P = 0.012). Women carrying both AMH Ser(49) and AMHR2 -482G alleles had highest E(2) levels (P = 0.001). For both polymorphisms no association with serum AMH or FSH levels was observed. CONCLUSIONS: Polymorphisms in the AMH and AMHR2 genes are associated with follicular phase E(2) levels, suggesting a role for AMH in the regulation of FSH sensitivity in the human ovary.

Serum anti-mullerian hormone levels reflect the size of the primordial follicle pool in mice.

Reproductive aging is the decline of female fertility with age. It is caused by the decrease in the number of growing follicles, resulting from primordial follicle pool depletion. Recently, we have shown that anti-Müllerian hormone (AMH) is produced by growing follicles, and studies in women indicate that serum AMH levels decrease with age and correlate with antral follicle count. However, whether serum AMH levels correlate directly with the size of the primordial follicle pool cannot be determined in women. In this work, we describe studies in mice in which we determined the dynamics of ovarian follicles during aging. Furthermore, we describe the development of a mouse AMH ELISA, allowing us to measure AMH levels in mice, for the first time. We observed that serum AMH levels decline with increasing age, whereas expression of AMH in individual growing follicles, studied by immunohistochemistry, did not change with age. Thus, the decline in serum AMH correlates directly with the decline in the number of growing follicles (r = 0.86, P < 0.0001). We observed that the number of growing follicles correlated with the number of primordial follicles (r = 0.93, P < 0.0001). Similarly, we found a strong correlation between AMH levels and number of primordial follicles (r = 0.83, P < 0.0001). In conclusion, serum AMH levels reflect the size of the primordial follicle pool in aging mice. Therefore, AMH is an excellent marker to assess the quantitative aspect of ovarian reserve, which may be useful for women at risk for early ovarian aging such as survivors of childhood cancers.