This Article Abstract Full Text (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lahlou, N. Articles by Roger, M. Search for Related Content PubMed PubMed Citation Articles by Lahlou, N. Articles by Roger, M. Pubmed/NCBI databases Gene GEO Profiles HomoloGene OMIM UniGene Compound via MeSH Substance via MeSH Genetics Home Reference Medline Plus Health Information Klinefelter's Syndrome Hazardous Substances DB MENOTROPINS TESTOSTERONE

Inhibin B and Anti-Müllerian Hormone, But Not Testosterone Levels, Are Normal in Infants with Nonmosaic Klinefelter Syndrome

Laboratoire de Biologie Hormonale (N.L., M.R.), Hôpital Saint-Vincent-de-Paul, 75014 Paris, France; Children’s Hospital of New York (I.F.), Division of Pediatric Endocrinology, Columbia University, New York, New York 10032; and Service d’Endocrinologie Pédiatrique (J.-C.C.), Hôpital Saint-Vincent-de-Paul, 75014 Paris, France

Address all correspondence and requests for reprints to: Dr. Najiba Lahlou, Biologie Hormonale, Hôpital Saint-Vincent-de-Paul, 82 avenue Denfert-Rochereau, 75014 Paris, France. E-mail: najiba.lahlou{at}svp.ap-hop-paris.fr.

	Abstract

Top Abstract Introduction Subjects and Methods Results Discussion Conclusion References

 
Klinefelter syndrome is a major cause of infertility in the male. Nevertheless, pregnancies were recently obtained by intracytoplasmic injection of sperm retrieved by surgery or ejaculation, underscoring the need to understand the role of Sertoli and Leydig cell secretions during development. In 18 infants with prenatally diagnosed homogenous 47,XXY karyotype, blood samples were taken from birth to 3 yr of age. Inhibin B (INHB), anti-Müllerian hormone (AMH), testosterone, FSH, and LH levels were compared with those in six adolescents with XXY karyotype and reference values established in 215 control infants. In XXY infants FSH, LH, INHB, and AMH did not differ from controls. Testosterone levels during the first trimester exhibited a physiological increase but were lower than in controls (P = 0.0001). Significant correlations were found between testosterone and LH (P < 0001), between INHB and FSH (P = 0.0011), and between AMH and INHB (P = 0.025). In XXY adolescents, AMH and INHB were undetectable. Our findings demonstrate that testosterone secretion is impaired in infants with Klinefelter syndrome. By contrast, INHB and AMH secretions were not altered, which raises the question of the mechanism(s) governing the decline of Sertoli cell function after puberty.

	Introduction

Top Abstract Introduction Subjects and Methods Results Discussion Conclusion References

 
KLINEFELTER SYNDROME IS a major cause of infertility in the male. In 1959 the syndrome was related to a specific chromosome abnormality with affected subjects bearing an extra X chromosome. The 47,XXY karyotype is usually acquired through a nondisjunction during parental gametogenesis, of either paternal (53%) or maternal (44%) origin. In only 3% of the cases, the origin is an error in postzygotic division, which results in mosaicism (review in Ref. 1). The syndrome affects about 1 in 500 boys (2, 3) and is responsible in most cases for complete azoospermia. Until recently the syndrome was recognized only at adolescence in the presence of characteristic clinical symptoms: tall stature, persistent pubertal gynecomastia, small testes, and azoospermia. Mental retardation has also been reported in a number of cases (1, 4). The main biological features, such as elevated gonadotropins and decreased testosterone, have been known for a long time (review in Ref. 1). The lack of inhibin secretion, which was more recently reported (5), emphasized the defect in mature Sertoli cell function in this syndrome.

A renewed interest in testis function in Klinefelter subjects arose from the reports of successful pregnancies obtained in nonmosaic 47,XXY subjects by intracytoplasmic sperm injection after surgical sperm extraction or ejaculation (review in Ref. 6). There are still some controversies regarding the possibility of intratesticular mosaicism in subjects with the nonmosaic 47,XXY blood karyotype. However, these results request further assessment of testis functions from birth to adulthood, with the aim of bringing future assistance to parents in their decision to continue pregnancy, when the chromosomal abnormality was prenatally diagnosed.

The aim of this work was to investigate early in life the secretion of Sertoli and Leydig cell hormones. Owing to prenatal diagnosis of Klinefelter syndrome, we had the opportunity to compare hormonal data in a significant number of 47,XXY infants and to a large cohort of normal infants and to demonstrate that Sertoli cell function appears to be normal in infants with nonmosaic Klinefelter syndrome, in contrast to impaired Leydig cell secretion.

	Subjects and Methods

Top Abstract Introduction Subjects and Methods Results Discussion Conclusion References

 
Subjects

Eighteen infants with homogenous 47,XXY karyotype were investigated for 1–3 yr (mean observation time, 610 d). The syndrome has been prenatally diagnosed by amniocentesis in the course of screening for Down syndrome or during the search of other chromosomal disorders. After comprehensive genetic counseling, including information on the high risk of infertility, parents chose to continue the pregnancy. They gave informed consent for a clinical and biological postnatal follow-up. The infants had normal height and weight at birth. Regular clinical and psychological consulting took place during the first 3 yr of life. Their growth rate and mental development for the period of observation was comparable with those of male infants with normal karyotype. Blood was collected at various intervals, one to three times during the first 3 yr of observation. A total of 50 individual samples were collected and distributed among five age groups, first month and 1–3, 4–8, 9–18, and 19–36 months. Their biological data were compared with reference values established in our laboratory from 215 infants investigated for various reasons and found to be free of any endocrine or metabolic disorder. In addition, gonadotropins and testis hormones were measured in six adolescents with nonmosaic 47,XXY karyotype, aged 14–18 yr.

Methods

Blood was collected in vacuum tubes, and the serum was immediately separated from cells and frozen. The specimens were shipped in dry ice and stored at –20 C until assayed.

FSH and LH were measured by a time-resolved fluorometric assay using Delfia reagents (Perkin Elmer Life Sciences, Courtaboeuf, France). Sensitivity for both assays was 0.01 IU/liter. Testosterone was measured by direct RIA using Orion reagents (CisBio International, Gif sur Yvette, France). Sensitivity was 0.01 ng/ml (0.05 nmol/liter). Inhibin B (INHB) was measured by an enzyme immunometric assay using Oxford Bio-Innovation reagents (Argene Biosoft, Varilhes, France), as described previously (7). Sensitivity was 6 pg/ml. Anti-Müllerian hormone (AMH) was measured by an enzyme immunometric assay using Immunotech reagents (Beckman Coulter, Villepinte, France). Sensitivity was 0.35 ng/ml (2.5 pmol/liter). SHBG was measured by means of Delfia reagents (Perkin Elmer Life Sciences). Sensitivity was 0.5 nmol/liter.

Statistics

The effects of age and clinical status (Klinefelter or control) were assessed by ANOVA using the Bonferroni/Dunn test. Correlations between hormone parameters were computed by means of the Spearman’s rank test.

	Results

Top Abstract Introduction Subjects and Methods Results Discussion Conclusion References

 
Both FSH and LH levels in Klinefelter infants were significantly higher in the period from birth to 3 months than in 4–18 month olds (P = 0.0012); they did not differ from controls (Table 1).

View larger version (21K): [in this window] [in a new window]   FIG. 1. Testosterone levels according to age in 47,XXY infants. Hatched area, Range of reference values in control infants (LL, lower limit; UL, upper limit = smoothed 5th and 95th percentiles). To convert nanograms per milliliter to nanomoles per liter, multiply by 3.4674.

INHB levels (Fig. 2) increased significantly from birth to 4 months (P = 0.04) and then decreased progressively; they did not differ from controls. They were strongly correlated with FSH levels (r = 0.607, P = 0.0011) as in controls (r = 0.58, P = 0.0009). In an XXY boy who was given im testosterone enanthate (100 mg/m²) on d 40 and on d 55 of age, both FSH and INHB levels markedly declined and then increased as soon as normal FSH was restored (Fig 3).

View larger version (17K): [in this window] [in a new window]   FIG. 2. Inhibin B levels according to age in 47,XXY infants. Hatched area, Range of reference values in control infants (same symbols as in Fig. 1).

View larger version (16K): [in this window] [in a new window]   FIG. 3. Changes in INHB, AMH, and FSH levels from birth to 8 months of age in an infant with nonmosaic 47,XXY karyotype, who has been treated with testosterone for 1 month (100 mg testosterone enanthate IM per square meter on d 40 and d 55 of age). INHB levels were markedly sensitive to changes in FSH levels. During testosterone administration, AMH level increased from 79–104 ng/ml despite the marked increase in testosterone level from 1.2–2.3 ng/ml (data not shown). All the observed changes in serum levels were far beyond intraassay variability.

View larger version (15K): [in this window] [in a new window]   FIG. 4. AMH levels according to age in 47,XXY infants. Hatched area, Range of reference values in control infants (same symbols as in Fig. 1).

	Discussion

Top Abstract Introduction Subjects and Methods Results Discussion Conclusion References

Leydig cell secretion of testosterone is impaired early in infants with Klinefelter syndrome

The impairment of testosterone secretion is a well-known feature of Klinefelter syndrome in adult males (1). It is generally accompanied by a moderate increase of LH. A preliminary study by Sorensen et al. (8) showed that testosterone in cord blood from three neonates with 47,XXY karyotype was slightly lower than in three controls with normal karyotype. We report here that in infants bearing the 47,XXY karyotype, testosterone exhibited a physiological increase during the first trimester, but the mean level was lower than in normal infants. By contrast, LH levels were similar to those in normal infants, which might denote some degree of resistance to LH, related to the abnormal Leydig cell karyotype, because SHBG levels did not differ from controls. On the other hand, we found a significant correlation between testosterone and LH levels, similar to that previously reported by our group in normal infants (9). This observation raises the question of possible consequences of the blunted neonatal testosterone peak on the adult reproductive axis. Suppressing the neonatal testosterone peak in rhesus monkeys by administration of a LHRH agonist delays puberty; impairs testis development and secretion; induces oligozoospermia or azoospermia (10); suppresses the sexual activity when adult (11); and decreases the hypothalamic sensitivity to the neuromediator amino acid glutamate (12), which plays a key role in the onset of puberty (13). Nevertheless, pubertal development in adolescents with Klinefelter syndrome seems to occur at the appropriate time (14). In addition, it has also been shown in monkeys that treatment with a LHRH antagonist during the neonatal period lowers the social rank of adults (15). Although there have been no systematic evaluations of the social rank in Klinefelter subjects, it should be noticed that mental retardation has been repeatedly reported in recent literature.

In contrast to the impairment in Leydig cell secretion, INHB and AMH secretions are normal in 47,XXY infants.

Inhibin B levels are normal and clearly dependent on FSH

In normal male infants, high serum levels of INHB have been reported by several investigators (16, 17, 18). Similar data were obtained in our control group. Interestingly, male infants with nonmosaic 47,XXY karyotype have normal INHB secretion all along the observation period. Inhibin secretion is highly sensitive to FSH, as in normal males. There appears to be a similar strong correlation between INHB and FSH in XXY and control infants, and additionally in a boy, transiently treated with testosterone, INHB and FSH changes were also strictly parallel. This is consistent with the increase of INHB levels observed by Main et al. (19) in an infant treated with FSH for hypogonadotropic hypogonadism.

Conversely in 10 infants with normal karyotype treated with human chorionic gonadotropin (hCG) for 1 wk (1500 IU hCG im every other day), INHB levels fell from 200 ± 28 to 95 ± 17 pg/ml, whereas FSH levels decreased to levels close to the detection limit (our unpublished personal data).

This indicates that inhibin secretion by testis cells, bearing this sex chromosome polysomy, is not impaired in young prepubertal boys, in contrast to adolescents and adults. Whether inhibin secretion in XXY infants results exclusively from Sertoli cells remains to be determined. It should be noticed, however, that immunolocalization studies only in adult testes support the assumption of a significant contribution of germ cells to INHB production (16, 20).

AMH secretion, although not correlated with FSH, is dependent on the trophic effect of FSH on Sertoli cells

AMH secretion is normal in infants with 47,XXY karyotype. AMH levels increased progressively from the first month of life through 6 months of age as in normal infants (21). AMH levels are not correlated with FSH, and the reverse relationship with testosterone, reported by our group in adolescent males (22), was not found here in neither Klinefelter nor control infants. By contrast and despite the different temporal changes, we found a significant correlation between AMH and INHB levels, previously unreported. It has been shown that FSH increased the proportion of proliferating Sertoli cells in cultured rat testis fragments (23). In FSH-deficient transgenic mice, AMH levels and Sertoli cell number are decreased but restored by administration of recombinant FSH (24). Moreover, in primates several reports from Ramaswamy et al. (25) and Simorangkir et al. (26) have emphasized the effect of FSH on Sertoli cell proliferation. Therefore, is it likely that the correlation between AMH and INHB reflects the trophic effect of FSH on Sertoli cells, rather than direct dependency of AMH on FSH. Furthermore, AMH secretion remained high beyond the age of 1 yr, whereas FSH levels were strongly suppressed, suggesting that once initiated, AMH secretion by Sertoli cells does not require significant FSH stimulation. In addition, as shown in Fig 3, the sharp decrease in FSH does not result in any decrease of AMH. Although anecdotic, this observation emphasizes the complexity of the mechanism regulating AMH secretion, which is still controversial. The reverse relationship with testosterone reported previously (22) is evident in boys treated for precocious puberty with a GnRH agonist: AMH levels significantly increased after testosterone suppression and are decreased after resumption of testis secretion (our personal unpublished data). On the other hand, short-term stimulation of testosterone secretion by hCG in prepubertal boys does not alter AMH (our unpublished data).

	Conclusion

Top Abstract Introduction Subjects and Methods Results Discussion Conclusion References

 
There is only scarce knowledge of testicular histology in prepubertal boys with Klinefelter syndrome. In three boys younger than 2 yr old, Mikamo et al. (27) found germ cells of normal appearance but reduced number and Sertoli cells with both normal appearance and number. Müller et al. (28) found normal seminiferous tubules, as far as germ cells were concerned, in 11 prepubertal boys. However, information regarding the status of Sertoli cells was lacking in the latter study. Our findings suggest that Sertoli cell functions are qualitatively and quantitatively normal in 47,XXY infants, which is in agreement with the early histological study by Mikamo et al. (27).

The role of germ cells in the regulation of Sertoli cell secretion is controversial. INHB secretion has been suggested to be up-regulated and AMH secretion to be down-regulated by germ cells (16, 29). The degeneration of germ cells after puberty could therefore impair INHB and AMH secretions. However, in nonmosaic Klinefelter syndrome, all Sertoli cells, when present in adult testis, have 47,XXY karyotype (30), and that could be enough to induce degeneration. On the other hand, in some subjects 47,XXY spermatogonia can undergo meiosis and give rise to X, Y, XX, and XY spermatozoa (30, 31). These findings have been challenged by other investigators who reported that only spermatogonia with a normal chromosomal pattern can produce mature sperm cells (32). However, both the successful intracytoplasmic sperm injection treatment of infertility in men with Klinefelter syndrome and the present evidence of normal Sertoli cell secretions in infants support the importance of elucidating the mechanism of secondary Sertoli and germ cell degeneration in adolescents with Klinefelter syndrome.

In addition, because there is experimental evidence in primates that testosterone secretion in the neonatal period can be important for adult sexual competence, the benefit of compensatory testosterone administration in Klinefelter infants during the first trimester of postnatal life deserves consideration.

	Acknowledgments

 
We are indebted to Mrs. Y. Le Bihan, Mrs. J. Le Fourn, and Mrs. N. Robert for excellent technical assistance. We also thank the Laboratory for Biological Standards (Mill Hill, London, UK) for the supply of international standards of pituitary hormones. We gratefully acknowledge the invaluable contribution of Dr. Judith Ross (Philadelphia, PA) in the revision of the manuscript.

	Footnotes

 
This work was supported by Columbia University (New York, New York) and Institut de Recherche Endocrinienne et Metabolique (Paris, France).

This work was presented in part at the 41st Annual Meeting of the European Society for Paediatric Endocrinology, Madrid, Spain, September 26–28, 2002.

Abbreviations: AMH, Anti-Müllerian hormone; hCG, human chorionic gonadotropin; INHB, inhibin B.

Received September 17, 2003.

Accepted December 23, 2003.

	References

Top Abstract Introduction Subjects and Methods Results Discussion Conclusion References

 

1. Smyth CM, Bremner WJ 1998 Klinefelter syndrome. Arch Intern Med 158:1309–1314[Abstract/Free Full Text]
2. Nielsen J, Wohlert M 1991 Sex chromosome abnormalities found among 39,910 newborn children: results from a 13-year incidence study in Arhus, Denmark. Birth Defects 26:209–223
3. Leonard JM, Bremner WJ, Capell PT, Paulsen CA 1975 Male hypogonadism: Klinefelter and Reifenstein syndrome. Birth Defects 11:17–22
4. Khalifa MM, Struthers JL 2002 Klinefelter syndrome is a common cause for mental retardation of unknown etiology among prepubertal males. Clin Genet 61:49–53[CrossRef][Medline]
5. Anawalt BD, Bebb RA, Matsumoto AM, Groome NP, Illingworth PJ, McNeilly AS, Bremner WJ 1996 Serum inhibin B levels reflect Sertoli cell function in normal men and men with testicular dysfunction. J Clin Endocrinol Metab 81:3341–3345[Abstract]
6. Bergere M, Wainer R, Nataf V, Bailly M, Gombault M, Ville Y, Selva J 2002 Biopsied testis cells of four 47,XXY patients: fluorescence in situ hybridization and ICSI results. Hum Reprod 17:32–37[Abstract/Free Full Text]
7. Lahlou N, Chabbert-Buffet N, Christin-Maitre S, Le Nestour E, Roger M, Bouchard P 1999 Main inhibitor of follicle stimulating hormone in the luteal-follicular transition: inhibin A, oestradiol, or inhibin B? Hum Reprod 14:1190–1193[Abstract/Free Full Text]
8. Sorensen K, Nielsen J, Wohlert M, Bennett P, Johnsen SG 1981 Serum testosterone of boys with karyotype 47,XXY (Klinefelter’s syndrome) at birth. Lancet ii:1112–1113
9. Gendrel D, Chaussain JL, Roger M, Job JL 1980 Simultaneous postnatal rise of plasma LH and testosterone in male infants. J Pediatr 97:600–602[CrossRef][Medline]
10. Mann DR, Gould KG, Collins DC, Wallen K 1989 Blockade of neonatal activation of the pituitary-testicular axis: effect of peripubertal luteinizing hormone and testosterone secretion and on testicular development in male monkeys. J Clin Endocrinol Metab 68:600–607[Abstract]
11. Eisler JA, Tannenbaum PL, Mann DR 1993 Neonatal testicular suppression with a GnRH agonist in rhesus monkeys: effects on adult endocrine function and behavior. Horm Behav 27:551–567[CrossRef][Medline]
12. Mann DR, Akinbami MA, Gould KG, Tanner JM, Wallen K 1993 Neonatal treatment of male monkeys with a gonadotropin-releasing hormone agonist alters differentiation of central nervous system centers that regulate sexual and skeletal development. J Clin Endocrinol Metab 76:1319–1324[Abstract]
13. Plant TM, Gay VL, Marshall GR, Arslan M 1989 Puberty in monkeys is triggered by chemical stimulation of hypothalamus. Proc Natl Acad Sci USA 86:2506–2510[Abstract/Free Full Text]
14. Christiansen P, Andersson AM, Skakkebaek NE 2003 Longitudinal studies of inhibin B levels in boys and young adults with Klinefelter syndrome. J Clin Endocrinol Metab 88:888–891[Abstract/Free Full Text]
15. Mann DR, Akinbami MA, Gould KG, Paul K, Wallon K 1998 Sexual maturation in male rhesus monkeys: importance of neonatal testosterone exposure and social rank. J Endocrinol 156:493–501[Abstract]
16. Andersson AM, Müller J, Skakkebaek NE 1998 Different roles of prepubertal and postpubertal germ cells and Sertoli cells in the regulation of serum inhibin B levels. J Clin Endocrinol Metab 83:4451–4458[Abstract/Free Full Text]
17. Byrd W, Bennett MJ, Carr BR, Dong Y, Wians F, Rainey W 1998 Regulation of biologically active dimeric inhibin A and B from infancy to adulthood in the male. J Clin Endocrinol Metab 83:2849–2854[Abstract/Free Full Text]
18. Crofton PM, Evans AEM, Groome NP, Taylor MRH, Holland CV, Kelnar CJH 2002 Inhibin B in boys from birth to adulthood: relationship with age, pubertal stage, FSH and testosterone. Clin Endocrinol (Oxf) 56 :215–221
19. Main KM, Schmidt IM, Toppari J, Skakkebaek NE 2002 Early postnatal treatment of hypogonadotropic hypogonadism with recombinant human FSH and LH. Eur J Endocrinol 146:75–79[Abstract]
20. Marchetti C, Hamdane, M, Mitchell V, Mayo K, Devisme L, Rigot JM, Beauvillain JC, Hermand E, Defossez A 2003 Immunolocalization of inhibin and activin and ßB subunits and expression of corresponding messenger RNAs in the human adult testis. Biol Reprod 68:230–235[Abstract/Free Full Text]
21. Lee MM, Donahue PK, Hasegawa T, Silverman B, Crist GB, Best S, Hasegawa Y, Noto RA, Schoenfeld D, MacLaughlin DT 1996 Mullerian inhibiting substance in humans: normal levels from infancy to adulthood. J Clin Endocrinol Metab 81:571576
22. Rey R, Lordereau-Richard I, Carel JC, Barbet P, Cate RL, Roger M, Chaussain JL, Josso N 1993 Anti-Müllerian hormone and testosterone serum levels are inversely related during normal and precocious development. J Clin Endocrinol Metab 77:1220–1226[Abstract]
23. Meehan T, Schlatt S, O’Bryan MK, de Kretser DM, Loveland KL 2000 Regulation of germ cell and Sertoli cell development by activin, follistatin, and FSH. Dev Biol 220:225–237[CrossRef][Medline]
24. Lukas-Croisier C, Lasala C, Nicaud J, Bedecarras P, Kumar TR, Dutertre M, Matzuk MM, Picard JY, Josso N, Rey R 2003 Follicle-stimulating hormone increases testicular anti-Mullerian hormone (AMH) production through Sertoli cell proliferation and a nonclassical adenosine 5'-monophosphate-mediated activation of the AMH gene. Mol Endocrinol 17:550–561[Abstract/Free Full Text]
25. Ramaswamy S, Marshall GR, Pohl CR, Friedman RL, Plant TM 2003 Inhibitory and stimulatory regulation of testicular inhibin B secretion by luteinizing hormone and follicle-stimulating hormone, respectively, in the rhesus monkeys (Macaca mulatta). Endocrinology 144:1175–1185[Abstract/Free Full Text]
26. Simorangkir DR, Marshall GR, Plant TM 2003 Sertoli cell proliferation during prepubertal development in the rhesus monkey (Macaca mulatta) is maximal during infancy when gonadotropin secretion is robust. J Clin Endocrinol Metab 88:4984–4989[Abstract/Free Full Text]
27. Mikamo K, Aguercif M, Hazeghi P, Martin-du-Pan R 1968 Chromatin-positive Klinefelter’s syndrome. A quantitative analysis of spermatogonial deficiency at 3, 4, and 12 months of age. Fertil Steril 19:731–739[Medline]
28. Müller J, Skakkebaek NE, Ratcliffe SG 1995 Quantified testicular histology in boys with sex chromosome abnormalities. Int J Androl 18:57–62[Medline]
29. Rajpert-De Meyts E, Jorgensen N, Graem N, Muller J, Cate RL, Skakkebaek NE 1999 Expression of anti-Mullerian hormone during normal and pathological gonadal development: association with differentiation of Sertoli and granulosa cells. J Clin Endocrinol Metab 84:3836–3844[Abstract/Free Full Text]
30. Foresta C, Galeazzi C, Bettella A, Marin P, Rossato M, Garolla A, Ferlin A 1999 Analysis of meiosis in intratesticular germ cells from subjects affected by the classic Klinefelter’s syndrome. J Clin Endocrinol Metab 84:3807–3810[Abstract/Free Full Text]
31. Hennebicq S, Pelletier R, Rousseaux S, Sele B 1999 Segregation of sex chromosomes in a Klinefelter patient (47,XXY). Proceedings of the 15th Annual Meeting of the European Society for Human Reproduction and Embryology, Tours, France, June 1999. Hum Reprod 14:66
32. Chevret E, Rousseaux S, Monteil M, Usson Y, Cozzi J, Pelletier R, Sele B 1997 Meiotic behaviour of sex chromosomes investigated by three-colour FISH on 35 142 sperm nuclei from two 47,XXY males. Hum Genet 99:407–412[CrossRef][Medline]

This article has been cited by other articles:

				S. E. Recabarren, T. Sir-Petermann, R. Rios, M. Maliqueo, B. Echiburu, R. Smith, P. Rojas-Garcia, M. Recabarren, and R. A. Rey Pituitary and Testicular Function in Sons of Women with Polycystic Ovary Syndrome from Infancy to Adulthood J. Clin. Endocrinol. Metab., September 1, 2008; 93(9): 3318 - 3324. [Abstract] [Full Text] [PDF]

				P. Bougneres, M. Francois, L. Pantalone, D. Rodrigue, C. Bouvattier, E. Demesteere, D. Roger, and N. Lahlou Effects of an Early Postnatal Treatment of Hypogonadotropic Hypogonadism with a Continuous Subcutaneous Infusion of Recombinant Follicle-Stimulating Hormone and Luteinizing Hormone J. Clin. Endocrinol. Metab., June 1, 2008; 93(6): 2202 - 2205. [Abstract] [Full Text] [PDF]

				L. Aksglaede, N. E. Skakkebaek, and A. Juul Abnormal Sex Chromosome Constitution and Longitudinal Growth: Serum Levels of Insulin-Like Growth Factor (IGF)-I, IGF Binding Protein-3, Luteinizing Hormone, and Testosterone in 109 Males with 47,XXY, 47,XYY, or Sex-Determining Region of the Y Chromosome (SRY)-Positive 46,XX Karyotypes J. Clin. Endocrinol. Metab., January 1, 2008; 93(1): 169 - 176. [Abstract] [Full Text] [PDF]

				L. Aksglaede, J. H Petersen, K. M Main, N. E Skakkebaek, and A. Juul High normal testosterone levels in infants with non-mosaic Klinefelter's syndrome Eur. J. Endocrinol., September 1, 2007; 157(3): 345 - 350. [Abstract] [Full Text] [PDF]

				R. Coutant, D. Mallet, N. Lahlou, N. Bouhours-Nouet, A. Guichet, L. Coupris, A. Croue, and Y. Morel Heterozygous Mutation of Steroidogenic Factor-1 in 46,XY Subjects May Mimic Partial Androgen Insensitivity Syndrome J. Clin. Endocrinol. Metab., August 1, 2007; 92(8): 2868 - 2873. [Abstract] [Full Text] [PDF]

				C. Mau Kai, K. M. Main, A. N. Andersen, A. Loft, N. E. Skakkebaek, and A. Juul Reduced Serum Testosterone Levels in Infant Boys Conceived by Intracytoplasmic Sperm Injection J. Clin. Endocrinol. Metab., July 1, 2007; 92(7): 2598 - 2603. [Abstract] [Full Text] [PDF]

				K. M Main, J. Toppari, and N. E Skakkebaek Gonadal development and reproductive hormones in infant boys Eur. J. Endocrinol., November 1, 2006; 155(suppl_1): S51 - S57. [Abstract] [Full Text] [PDF]

				L. Soriano-Guillen, V. Mitchell, J.-C. Carel, P. Barbet, M. Roger, and N. Lahlou Activating Mutations in the Luteinizing Hormone Receptor Gene: A Human Model of Non-Follicle-Stimulating Hormone-Dependent Inhibin Production and Germ Cell Maturation J. Clin. Endocrinol. Metab., August 1, 2006; 91(8): 3041 - 3047. [Abstract] [Full Text] [PDF]

				U. Eiholzer, D. l'Allemand, V. Rousson, M. Schlumpf, T. Gasser, J. Girard, A. Gruters, and M. Simoni Hypothalamic and Gonadal Components of Hypogonadism in Boys with Prader-Labhart- Willi Syndrome J. Clin. Endocrinol. Metab., March 1, 2006; 91(3): 892 - 898. [Abstract] [Full Text] [PDF]

				A.-M. Suomi, K. M. Main, M. Kaleva, I. M. Schmidt, M. Chellakooty, H. E. Virtanen, K. A. Boisen, I. N. Damgaard, C. M. Kai, N. E. Skakkebaek, et al. Hormonal Changes in 3-Month-Old Cryptorchid Boys J. Clin. Endocrinol. Metab., March 1, 2006; 91(3): 953 - 958. [Abstract] [Full Text] [PDF]

				H. Lefevre, C. Bouvattier, N. Lahlou, C. Adamsbaum, P. Bougneres, and J.-C. Carel Prepubertal gynecomastia in Peutz-Jeghers syndrome: incomplete penetrance in a familial case and management with an aromatase inhibitor Eur. J. Endocrinol., February 1, 2006; 154(2): 221 - 227. [Abstract] [Full Text] [PDF]

				L. Aksglaede, A. M. Wikstrom, E. R.-D. Meyts, L. Dunkel, N. E. Skakkebaek, and A. Juul Natural history of seminiferous tubule degeneration in Klinefelter syndrome Hum. Reprod. Update, January 1, 2006; 12(1): 39 - 48. [Abstract] [Full Text] [PDF]

				A. R. Zinn, P. Ramos, F. F. Elder, K. Kowal, C. Samango-Sprouse, and J. L. Ross Androgen Receptor CAGn Repeat Length Influences Phenotype of 47,XXY (Klinefelter) Syndrome J. Clin. Endocrinol. Metab., September 1, 2005; 90(9): 5041 - 5046. [Abstract] [Full Text] [PDF]

				Y. Lue, J. D. Jentsch, C. Wang, P. N. Rao, A. P. Sinha Hikim, W. Salameh, and R. S. Swerdloff XXY Mice Exhibit Gonadal and Behavioral Phenotypes Similar to Klinefelter Syndrome Endocrinology, September 1, 2005; 146(9): 4148 - 4154. [Abstract] [Full Text] [PDF]

				J. Young, P. Chanson, S. Salenave, M. Noel, S. Brailly, M. O'Flaherty, G. Schaison, and R. Rey Testicular Anti-Mullerian Hormone Secretion Is Stimulated by Recombinant Human FSH in Patients with Congenital Hypogonadotropic Hypogonadism J. Clin. Endocrinol. Metab., February 1, 2005; 90(2): 724 - 728. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lahlou, N. Articles by Roger, M. Search for Related Content PubMed PubMed Citation Articles by Lahlou, N. Articles by Roger, M. Pubmed/NCBI databases Gene GEO Profiles HomoloGene OMIM UniGene Compound via MeSH Substance via MeSH Genetics Home Reference Medline Plus Health Information Klinefelter's Syndrome Hazardous Substances DB MENOTROPINS TESTOSTERONE