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1.
Hum Reprod ; 26(3): 724-8, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21227944

RESUMEN

DAX1/NR0B1 mutations are responsible for X-linked congenital adrenal hypoplasia (AHC) associated with hypogonadotropic hypogonadism (HH). Few data are available concerning testicular function and fertility in men with DAX1 mutations. Azoospermia as well as failure of gonadotrophin treatment have been reported. We induced spermatogenesis in a patient who has a DAX1 mutation (c.1210C>T), leading to a stop codon in position 404 (p.Gln404X). His endocrine testing revealed a low testosterone level at 1.2 nmol/l (N: 12-40) with low FSH and LH levels at 2.1 IU/l (N: 1-5 IU/l) and 0.1 IU/l (N: 1-4 IU/l), respectively. Baseline semen analysis revealed azoospermia. Menotropin (Menopur(®):150 IU, three times weekly) and human chorionic gonadotrophin (1500 IU, twice weekly) were used. After 20 months of treatment, as azoospermia persisted, bilateral multiple site testicular biopsies were performed. Histology revealed severe hypospermatogenesis. Rare spermatozoa were extracted from the right posterior fragment and ICSI was performed. Four embryos were obtained and, after a frozen-thawed single-embryo transfer, the patient's wife became pregnant and gave birth to a healthy boy. We report the first case of paternity after TESE-ICSI in a patient with DAX1 mutation, giving potential hope to these patients to father non-affected children. Furthermore, this case illustrates the fact that patients with X-linked AHC have a primary testicular defect in addition to HH.


Asunto(s)
Receptor Nuclear Huérfano DAX-1/genética , Hipogonadismo/genética , Infertilidad Masculina/genética , Infertilidad Masculina/terapia , Técnicas Reproductivas Asistidas , Hiperplasia Suprarrenal Congénita/genética , Hiperplasia Suprarrenal Congénita/patología , Hiperplasia Suprarrenal Congénita/fisiopatología , Hiperplasia Suprarrenal Congénita/terapia , Insuficiencia Suprarrenal , Adulto , Receptor Nuclear Huérfano DAX-1/química , Enfermedades Genéticas Ligadas al Cromosoma X/genética , Enfermedades Genéticas Ligadas al Cromosoma X/patología , Enfermedades Genéticas Ligadas al Cromosoma X/fisiopatología , Enfermedades Genéticas Ligadas al Cromosoma X/terapia , Humanos , Insuficiencia Corticosuprarrenal Familiar , Infertilidad Masculina/tratamiento farmacológico , Masculino , Túbulos Seminíferos/citología , Túbulos Seminíferos/patología , Espermatogénesis/efectos de los fármacos , Resultado del Tratamiento
2.
Minerva Endocrinol ; 35(2): 73-86, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20595937

RESUMEN

Steroidogenic factor 1 (SF1, NR5A1, Ad4BP) is a nuclear receptor and regulator of multiple genes involved in adrenal and gonadal development, steroidogenesis, and the reproductive axis. Complete deletion of Nr5a1 in XY mice results in adrenal and gonadal agenesis, female external genitalia and presence of Müllerian structures. These findings were first reported in the early 1990s. Subsequently, NR5A1 mutations were found in two 46,XY phenotypic females with Müllerian structures and adrenal failure and in one 46,XX female with adrenal failure. More recently, heterozygous NR5A1 mutations have been identified in a substantial proportion of patients with 46,XY disorders of sex development (46,XY DSD) without adrenal insufficiency. Most of these individuals display severe underandrogenization with ambiguous genitalia at birth, partial gonadal dysgenesis, and absence of Müllerian structures or remnants. Some of the patients have a milder phenotype such as hypospadias and cryptorchidism, due to less severe defects in androgen synthesis. Testosterone, inhibin B and AMH are usually low indicating a partial (or sometimes progressive) form of gonadal dysgenesis in most cases. However, normal testosterone production at birth might also be present. The frequency of NR5A1 mutations in otherwise unexplained 46,XY DSD with underandrogenization and partial testicular dysgenesis has been estimated to be about 15%. Furthermore, NR5A1 mutations have now been found in women with familial and sporadic 46,XX primary ovarian insufficiency without adrenal failure. These human phenotypes associated with NR5A1 mutations show that SF-1 is a key factor involved in both human testis and ovarian development, but that human adrenal development seems to be more resistant to the effects of SF-1 haploinsufficiency than gonadal development. Patients with 46,XY DSD and mild underandrogenization due to partial testicular dysgenesis should possibly be assigned to the male sex, as small testes with Leydig, Sertoli and germ cells are present in almost all cases. Additionally, spontaneous virilization in puberty might be possible in patients with NR5A1 mutations. However, fertility options and the risk of testicular malignancy and adrenal insufficiency in adulthood are unknown and need to be investigated in long-term outcome studies.


Asunto(s)
Disgenesia Gonadal 46 XY/diagnóstico , Disgenesia Gonadal 46 XY/genética , Mutación , Factor Esteroidogénico 1/genética , Glándulas Suprarrenales/anomalías , Insuficiencia Suprarrenal/genética , Animales , Femenino , Heterocigoto , Humanos , Inhibinas/genética , Masculino , Fenotipo , Desarrollo Sexual/genética , Testosterona/genética
3.
J Med Genet ; 45(9): e1, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18762570

RESUMEN

Adrenal hypoplasia congenita (AHC) can occur due to deletions or mutations in the DAX 1 (NR0B1) gene on the X chromosome (OMIM 300200). This form of AHC is therefore predominantly seen in boys. Deletion of the DAX 1 gene can also be part of a larger contiguous deletion including the centromeric dystrophin and glycerol kinase (GK) genes. We report a girl with a de novo deletion at Xp21.2 on the maternal chromosome, including DAX1, the GK gene and 3' end of the dystrophin gene, who presented with salt losing adrenal insufficiency and moderate developmental delay, but relatively mild features of muscular dystrophy. Investigation using the androgen receptor as a marker gene identified skewed inactivation of the X chromosome. In the patient's leucocytes, the paternal X chromosome was completely inactive, but in muscle 20% of the active chromosomes were of paternal origin. Thus skewed X inactivation (deletion on the active maternal X chromosome with an inactive paternal X chromosome) is associated with AHC in a female. Variability in X inactivation between tissues may account for the pronounced salt loss and adrenal insufficiency but mild muscular dystrophy.


Asunto(s)
Insuficiencia Suprarrenal/congénito , Insuficiencia Suprarrenal/genética , Inactivación del Cromosoma X , Insuficiencia Suprarrenal/diagnóstico , Receptor Nuclear Huérfano DAX-1 , Proteínas de Unión al ADN/genética , Distrofina/genética , Femenino , Eliminación de Gen , Ligamiento Genético , Glicerol Quinasa/genética , Glicerol Quinasa/metabolismo , Humanos , Recién Nacido , Fenotipo , Receptores de Ácido Retinoico/genética , Proteínas Represoras/genética
5.
J Clin Invest ; 105(3): 321-8, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10675358

RESUMEN

Mutations in the DAX1 gene cause X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HHG). In affected boys, primary adrenal insufficiency occurs soon after birth or during early childhood; HHG is recognized at the expected time of puberty. In this report, we describe the novel phenotype of a man who presented with apparently isolated adrenal insufficiency at 28 years of age. Examination revealed partial pubertal development and undiagnosed incomplete HHG. Gonadotropin therapy did not improve his marked oligospermia, suggesting a concomitant primary testicular abnormality. Genomic analysis revealed a novel missense mutation, I439S, in DAX1. The mutant DAX-1 protein was studied for its ability to function as a transcriptional repressor of target genes. Consistent with the patient's mild clinical phenotype, the I439S mutation conferred intermediate levels of repressor activity of DAX-1 when compared with mutations associated with classic AHC. This unique case extends the clinical spectrum of AHC to include delayed-onset primary adrenal insufficiency in adulthood and milder forms of HHG. Furthermore, in accordance with findings in Ahch (Dax1) knockout mice, the clinical features in this patient suggest that DAX-1 function is required for spermatogenesis in humans, independent of its known effects on gonadotropin production.


Asunto(s)
Glándulas Suprarrenales/fisiopatología , Proteínas de Unión al ADN/genética , Hipogonadismo/genética , Mutación , Receptores de Ácido Retinoico/genética , Proteínas Represoras , Factores de Transcripción/genética , Adulto , Edad de Inicio , Animales , Receptor Nuclear Huérfano DAX-1 , Humanos , Hipogonadismo/fisiopatología , Masculino , Ratones , Ratones Noqueados
6.
J Clin Endocrinol Metab ; 91(6): 2428-31, 2006 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16569739

RESUMEN

CONTEXT: Combined 17alpha-hydroxylase/17,20-lyase deficiency is a rare cause of congenital adrenal hyperplasia and hypogonadism. Novel single amino acid changes in P450c17 provide potentially important insights into key structural domains for enzyme function. OBJECTIVE, DESIGN, AND SETTING: We report a novel missense mutation in P450c17 in a 17-yr-old female presenting with a malignant mixed germ cell tumor with yolk sac elements who demonstrated clinical and biochemical features of combined 17alpha-hydroxylase/17,20-lyase deficiency. METHODS: Quantitative urinary steroid analysis was performed by high resolution gas chromatography. All eight coding exons of CYP17 were PCR amplified and sequenced. The position of arginine at codon 96 was modeled using the CYP17 structure 2c17 (www.rcsb.org). The CYP17 genes were subcloned into pcDNA3, expressed in HEK-293 cells, and chromatographed. PATIENT AND RESULTS: 17alpha-Hydroxylase deficiency was confirmed by marked reductions in urinary and serum cortisol, androgens, and estradiol. Mutational analysis revealed a novel homozygous R96Q missense mutation in P450c17, affecting an amino acid in a key substrate-binding region of the enzyme, leading to complete inactivity. CONCLUSION: The description of a second missense mutation at codon 96 (R96W and R96Q) in the substrate-binding region of P450c17 provides strong evidence for the key role of this amino acid in 17alpha-hydroxylase/17,20-lyase function. An association between a malignant germ cell tumor and 17alpha-hydroxylase deficiency has not been reported previously, although the presence of gonadoblastoma in the ovary of a patient with this condition has recently been described.


Asunto(s)
Hiperplasia Suprarrenal Congénita/genética , Mutación Puntual , Esteroide 17-alfa-Hidroxilasa/genética , Adolescente , Femenino , Humanos , Modelos Moleculares , Mutación Missense , Esteroide 17-alfa-Hidroxilasa/análisis
7.
J Clin Endocrinol Metab ; 90(3): 1849-55, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15598687

RESUMEN

It has recently been shown that loss-of-function mutations of the G protein-coupled receptor (GPR)54 lead to isolated hypogonadotropic hypogonadism (IHH) in mice and humans. Such mutations are thought to be rare, even within the clinical IHH population, and only a handful of alleles have been described, making further screening of IHH populations imperative. We examined the genes encoding GPR54 and its putative endogenous ligand, kisspeptin-1, for mutations in a cohort of 30 patients with normosmic HH or delayed puberty. One subject with HH, of mixed Turkish-Cypriot and Afro-Caribbean ancestry, was found to be a compound heterozygote for two previously undescribed missense mutations in GPR54: cysteine 223 to arginine (C223R) in the fifth transmembrane helix and arginine 297 to leucine (R297L) in the third extracellular loop. Assessed in vitro using a previously described sensitive signaling assay in cells stably expressing GPR54, the C223R variant was found to exhibit profoundly impaired signaling, whereas the R297L variant showed a mild reduction in ligand-stimulated activity across the ligand dose range. These novel mutations provide further evidence that human HH may be caused by loss-of-function mutations in GPR54.


Asunto(s)
Hipogonadismo/genética , Mutación Missense , Receptores de Neuropéptido/genética , Adolescente , Secuencia de Aminoácidos , Femenino , Pruebas Genéticas , Humanos , Hipogonadismo/epidemiología , Masculino , Datos de Secuencia Molecular , Polimorfismo de Nucleótido Simple , Prevalencia , Receptores Acoplados a Proteínas G , Receptores de Kisspeptina-1
8.
Trends Endocrinol Metab ; 9(5): 169-75, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18406261

RESUMEN

Mutations in a gene referred to as Dax-1 cause an X-linked form of adrenal hypoplasia congenita (AHC). The disorder is limited to males and is characterized by neonatal adrenal insufficiency and failure to undergo puberty because of hypogonadotropic hypogonadism. Consistent with these clinical manifestations, the Dax-1 gene is expressed in the adrenal gland, gonads, hypothalamus and pituitary gland. The DAX-1 protein is structurally related to orphan nuclear receptors, although it lacks the characteristic zinc finger DNA-binding domain that is highly conserved in other members of this family. Dax-1 has been shown to repress the transcription of genes that are regulated by another nuclear receptor, steroidogenic factor-1 (SF-1). AHC mutations in Dax-1 eliminate its repressive activity. Genetic testing for Dax-1 mutations will enhance our ability to diagnose and treat AHC. Studies of the biological role of Dax-1 will provide new insights into the development and function of the adrenal gland and the reproductive axis.

9.
J Clin Endocrinol Metab ; 84(12): 4501-9, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10599709

RESUMEN

X-linked adrenal hypoplasia congenita (AHC) is a disorder associated with primary adrenal insufficiency and hypogonadotropic hypogonadism (HH). The gene responsible for X-linked AHC, DAX1, encodes a member of the nuclear hormone receptor superfamily. We studied an extended kindred with AHC and HH in which two males (the proband and his nephew) were affected with a nucleotide deletion (501delA). The proband's mother, sister, and niece were heterozygous for this frameshift mutation. At age 27 yr, after 7 yr of low dose hCG therapy, the proband underwent a testicular biopsy revealing rare spermatogonia and Leydig cell hyperplasia. Despite steadily progressive doses of hCG and Pergonal administered over a 3-yr period, the proband remained azoospermic. The proband's mother, sister (obligate carrier), and niece all had a history of delayed puberty, with menarche occurring at ages 17-18 yr. Baseline patterns of pulsatile gonadotropin secretion and gonadotropin responsiveness to exogenous pulsatile GnRH were examined in the affected males. LH, FSH, and free alpha-subunit were determined during 12.5-24 h of frequent blood sampling (every 10 min). Both patients then received pulsatile GnRH (25 ng/kg) sc every 2 h for 6-7 days. Gonadotropin responses to a single GnRH pulse iv were monitored daily to assess the pituitary responsiveness to exogenous GnRH. In the proband, FSH and LH levels demonstrated a subtle, but significant, response to GnRH over the week of pulsatile GnRH therapy. Free alpha-subunit levels demonstrated an erratic pattern of secretion at baseline and no significant response to pulsatile GnRH. We conclude that 1) affected males with AHC/HH may have an intrinsic defect in spermatogenesis that is not responsive to gonadotropin therapy; 2) female carriers of DAX1 mutations may express the phenotype of delayed puberty; and 3) although affected individuals display minimal responses to pulsatile GnRH, as observed in other AHC kindreds, subtle differences in gonadotropin patterns may nevertheless exist between affected individuals within a kindred.


Asunto(s)
Insuficiencia Suprarrenal/genética , Proteínas de Unión al ADN/genética , Mutación , Fenotipo , Receptores de Ácido Retinoico/genética , Proteínas Represoras , Factores de Transcripción/genética , Cromosoma X , Adolescente , Insuficiencia Suprarrenal/patología , Insuficiencia Suprarrenal/fisiopatología , Receptor Nuclear Huérfano DAX-1 , Femenino , Hormona Folículo Estimulante/metabolismo , Ligamiento Genético , Hormona Liberadora de Gonadotropina/administración & dosificación , Hormona Liberadora de Gonadotropina/uso terapéutico , Humanos , Hormona Luteinizante/metabolismo , Masculino , Linaje , Periodicidad , Pubertad Tardía/genética , Espermatogénesis , Testículo/patología , Testosterona/sangre
10.
J Clin Endocrinol Metab ; 86(7): 3171-5, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11443184

RESUMEN

DAX-1 is an orphan nuclear receptor that plays a key role in the development and function of the adrenal gland and hypothalamic-pituitary gonadal axis. Mutations in the gene encoding DAX-1 result in X-linked adrenal hypoplasia congenita (AHC). Affected boys typically present with primary adrenal failure in infancy or childhood and hypogonadotropic hypogonadism at the time of puberty. The majority of DAX1 mutations described to date are nonsense or frameshift mutations that result in premature truncation of the DAX-1 protein and loss of DAX-1 repressor function. Relatively few missense mutations in DAX1 have been reported. Here, we describe missense mutations in three additional families with X-linked AHC. When combined with previous reports, the DAX1 missense mutations appear to cluster within restricted regions of the putative ligand-binding domain of DAX-1 and affect amino acids that are evolutionarily conserved, suggesting that these regions correspond to critical functional domains. Transcription assays, using a variety of artificial and native target genes, were performed to assess the effects of these mutations on the function of DAX-1. All DAX-1 missense mutant constructs showed marked loss of repressor function, with the exception of I439S, a mutation previously shown to be associated with delayed-onset adrenal failure and incomplete hypogonadotropic hypogonadism. These data indicate that most DAX1 missense mutations associated with classic AHC exhibit marked loss of function. The locations of these mutations thereby identify important functional domains in the carboxyl-terminus of the protein.


Asunto(s)
Insuficiencia Suprarrenal/genética , Proteínas de Unión al ADN/genética , Mutación Missense , Receptores de Ácido Retinoico/genética , Proteínas Represoras , Factores de Transcripción/genética , Transcripción Genética , 17-alfa-Hidroxiprogesterona/sangre , Hormona Adrenocorticotrópica/sangre , Aldosterona/sangre , Línea Celular , Cortodoxona/sangre , Receptor Nuclear Huérfano DAX-1 , Embrión de Mamíferos , Ligamiento Genético , Humanos , Hidrocortisona/sangre , Hiperpotasemia/genética , Hiponatremia/genética , Lactante , Recién Nacido , Riñón , Masculino , Renina/sangre , Cromosoma X
11.
J Clin Endocrinol Metab ; 84(2): 504-11, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10022408

RESUMEN

Adrenal hypoplasia congenita (AHC) is an X-linked disorder caused by mutations in a gene referred to as DAX-1. AHC is characterized by adrenal insufficiency and failure to undergo puberty because of hypogonadotropic hypogonadism. The DAX-1 protein is structurally related to orphan nuclear receptors, although it lacks the characteristic zinc finger DNA-binding domain that is highly conserved in other members of this family. In this report, we describe the clinical features and genetic alterations in six families with AHC. These patients reveal the variable clinical presentation of adrenal insufficiency in AHC and underscore the importance of considering this diagnosis. Nonsense mutations that introduce a stop codon were found in three cases (W171X, W171X, Y399X). Frameshift mutations (405delT, 501delA, and 702delC), each of which resulted in a premature stop codon at amino acid 263, were found in the other three families. Three of these mutations (Y399X, 405delT, 702delC) are novel. Using transient gene expression assays to assess DAX-1 function, these mutations were shown to eliminate the ability of DAX-1 to repress the transcription of genes that are stimulated by a related nuclear receptor, steroidogenic factor-1. These studies reveal the variable clinical presentation of DAX-1 mutations and emphasize the value of genetic testing in boys with primary adrenal insufficiency and suspected X-linked AHC.


Asunto(s)
Insuficiencia Suprarrenal/genética , Proteínas de Unión al ADN/genética , Mutación , Receptores de Ácido Retinoico/genética , Proteínas Represoras , Factores de Transcripción/genética , Insuficiencia Suprarrenal/congénito , Adulto , Niño , Preescolar , Codón , Receptor Nuclear Huérfano DAX-1 , Análisis Mutacional de ADN , Femenino , Mutación del Sistema de Lectura , Ligamiento Genético , Humanos , Hipogonadismo/genética , Lactante , Recién Nacido , Masculino , Linaje , Factor Esteroidogénico 1 , Cromosoma X
12.
J Clin Endocrinol Metab ; 84(12): 4497-500, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10599708

RESUMEN

Although delayed puberty is relatively common and often familial, its molecular and pathophysiologic basis is poorly understood. In contrast, the molecular mechanisms underlying some forms of hypogonadotropic hypogonadism (HH) are clearer, following the description of mutations in the genes KAL, GNRHR, and PROP1. Mutations in another gene, DAX1 (AHC), cause X-linked adrenal hypoplasia congenita and HH. Affected boys usually present with primary adrenal failure in infancy or childhood and HH at the expected time of puberty. DAX1 mutations have also been reported to occur with a wider spectrum of clinical presentations. These cases include female carriers of DAX1 mutations with marked pubertal delay and a male with incomplete HH and mild adrenal insufficiency in adulthood. Given this emerging phenotypic spectrum of clinical presentation in men and women with DAX1 mutations, we hypothesized that DAX1 might be a candidate gene for mutation in patients with idiopathic sporadic or familial HH or constitutional delay of puberty. Direct sequencing of DAX1 was performed in 106 patients, including 85 (80 men and 5 women) with sporadic HH or constitutional delay of puberty and patients from 21 kindreds with familial forms of these disorders. No DAX1 mutations were found in these groups of patients, although silent single nucleotide polymorphisms were identified (T114C, G498A). This study suggests that mutations in DAX1 are unlikely to be a common cause of HH or pubertal delay in the absence of a concomitant history of adrenal insufficiency.


Asunto(s)
Análisis Mutacional de ADN , Proteínas de Unión al ADN/genética , Hipogonadismo/genética , Pubertad Tardía/genética , Receptores de Ácido Retinoico/genética , Proteínas Represoras , Factores de Transcripción/genética , Receptor Nuclear Huérfano DAX-1 , Femenino , Ligamiento Genético , Humanos , Masculino , Cromosoma X
13.
Pediatrics ; 102(2 Pt 1): 342-5, 1998 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9685436

RESUMEN

OBJECTIVE: To determine the influence of birth weight on the first year response to growth hormone (GH) replacement in children with isolated GH insufficiency. STUDY DESIGN: A longitudinal study of response to daily GH treatment (15-26 IU/m2/week) was performed in 16 singleton Caucasian prepubertal children (11 boys, 5 girls) with isolated GH insufficiency (peak GH response to insulin tolerance test <13.5 mU/L) attending a pediatric endocrinology clinic. Change in height velocity standard deviation scores, during the 6 to 12 months before starting GH and the 12 months after, were used to reflect responsivity to GH treatment. Potential influencing variables considered by regression analysis were birth weight standard deviation score (BWSDS), peak GH response to insulin tolerance testing, midparental height standard deviation score, age at treatment, and dose of GH administered. RESULTS: Mean BWSDS was -0.51 (SD, 1.0). Change in height velocity standard deviation score was correlated positively with BWSDS (r = 0.64) and negatively with peak GH (r = -0.59). Stepwise linear regression analysis confirmed the influence of BWSDS on response to GH treatment. CONCLUSIONS: The continuum of birth weight influences initial responsivity to GH treatment in GH-insufficient children. This may reflect relative insensitivity in the growth hormone or insulin-like growth factor axis. The influence of birth weight on final height and benefit of using higher doses of GH in these children remains to be seen.


Asunto(s)
Peso al Nacer , Estatura/efectos de los fármacos , Enanismo Hipofisario/terapia , Hormona del Crecimiento/administración & dosificación , Niño , Preescolar , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Enanismo Hipofisario/etiología , Femenino , Retardo del Crecimiento Fetal/etiología , Retardo del Crecimiento Fetal/terapia , Humanos , Recién Nacido Pequeño para la Edad Gestacional , Masculino , Pronóstico , Análisis de Regresión , Resultado del Tratamiento
14.
Mol Cell Endocrinol ; 185(1-2): 17-25, 2001 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-11738790

RESUMEN

SF-1 (steroidogenic factor-1) (NR5A1) and DAX-1 (dosage-sensitive sex-reversal, adrenal hypoplasia congenital, X chromosome) (NR0B1) are orphan nuclear receptors that are expressed in the adrenal gland, gonads, ventromedial hypothalamus (VMH), and pituitary gonadotrope cells. The function of these genes has been clarified by examining the consequences of naturally occurring mutations in humans, as well as targeted disruption of the genes in mice. Mutations in DAX1 cause adrenal hypoplasia congenita (AHC), an X-linked disorder characterized by adrenal insufficiency and failure to undergo puberty because of hypogonadotropic hypogonadism. Most DAX1 mutations introduce frameshifts and/or cause premature termination of the protein. Relatively few missense mutations have been described and all are located within the carboxy-terminal half of the protein. Transfection assays demonstrate that AHC-associated DAX1 mutations abrogate its ability to act as a transcriptional repressor of SF-1. Most boys affected with AHC present with adrenal insufficiency in early infancy, although a significant fraction present in later childhood or even as young adults. The degree of gonadotropin deficiency is also variable. With the exception of one mild missense DAX1 mutation, genotype-phenotype correlations have been elusive, suggesting an important role for modifier genes. Targeted mutagenesis of Dax1 (Ahch) in mice reveals an additional role in testis development and spermatogenesis. Similar abnormalities appear to be present in humans. Targeted mutagenesis of Sf1 (FtzF1) prevents gonadal and adrenal development, and causes male-to-female sex-reversal. A human XY individual with a heterozygous SF1 mutation presented with adrenal insufficiency and complete sex-reversal; this DNA-binding domain mutation prevents SF-1 stimulation of its target genes. In addition to their clinical relevance, studies of SF1 and DAX1 are proving useful for unraveling the genetic pathways that govern adrenal and gonadal development.


Asunto(s)
Proteínas de Unión al ADN/genética , Mutación , Receptores de Ácido Retinoico/genética , Proteínas Represoras , Factores de Transcripción/genética , Glándulas Suprarrenales/crecimiento & desarrollo , Animales , Receptor Nuclear Huérfano DAX-1 , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/fisiología , Femenino , Factores de Transcripción Fushi Tarazu , Variación Genética , Proteínas de Homeodominio , Humanos , Masculino , Mutagénesis Sitio-Dirigida , Fenotipo , Receptores Citoplasmáticos y Nucleares , Receptores de Ácido Retinoico/metabolismo , Receptores de Ácido Retinoico/fisiología , Factor Esteroidogénico 1 , Testículo/crecimiento & desarrollo , Factores de Transcripción/metabolismo , Factores de Transcripción/fisiología
15.
Mol Cell Endocrinol ; 179(1-2): 89-96, 2001 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-11420133

RESUMEN

Pulsatile GnRH acts at the GnRH receptor on gonadotropes to stimulate gonadotropin gene expression, hormone synthesis and secretion. The pituitary gonadotropins, LH and FSH, stimulate steroid production and gametogenesis in males and in females. Gonadotropin production thus requires the normal development and function of hypothalamic GnRH-producing neurons and pituitary gonadotrope cells. Genes involved in gonadotrope development and/or gene expression include SF1, DAX1, KAL, GNRHR, PC1, HESX1, LHX3, PROP1, LH beta, and FSH beta. Given the complex control of gonadotropin biosynthesis and secretion, it is not surprising that genetic abnormalities have been identified at several of these steps. Some of the mutations that will be reviewed include: (1) SF1 and DAX1-orphan nuclear receptors that are expressed at multiple levels throughout the reproductive axis; (2) KAL-X-linked Kallmann syndrome, where there is abnormal development of hypothalamic GnRH-producing neurons; (3) PC1-causing abnormal processing of GnRH and GNRHR mutations that impair action at the GnRH receptor; (4) HESX1, LHX3, PROP1-abnormal development/function of the gonadotrope cell lineage; (5) LH beta and FSH beta-mutations in the gonadotropin genes that cause structural abnormalities in the hormones. Although all of these gene defects lead to gonadotropin deficiency, each disorder is associated with unique phenotypic or hormonal features. Characterization of the molecular basis of gonadotropin deficiency is useful for directing therapy and for genetic counseling. Identification of these mutations also provides insight into the pathways that govern reproduction.


Asunto(s)
Trastornos del Desarrollo Sexual/genética , Trastornos del Desarrollo Sexual/metabolismo , Hormona Liberadora de Gonadotropina/metabolismo , Gonadotropinas/metabolismo , Adenohipófisis/fisiopatología , Animales , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Femenino , Factores de Transcripción Fushi Tarazu , Gametogénesis/fisiología , Hormona Liberadora de Gonadotropina/genética , Gonadotropinas/genética , Proteínas de Homeodominio , Humanos , Síndrome de Kallmann/genética , Síndrome de Kallmann/fisiopatología , Masculino , Mutación/genética , Adenohipófisis/crecimiento & desarrollo , Receptores Citoplasmáticos y Nucleares , Factor Esteroidogénico 1 , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
16.
Eur J Endocrinol ; 142(4): 359-64, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10754477

RESUMEN

OBJECTIVE: Previous studies have suggested that post-irradiation GH insufficiency results from a loss of GHRH secretion, since many patients were able to release GH following exogenous GHRH stimulation. However, supramaximal doses of GHRH were used and the response may decline with time after radiotherapy. We re-evaluated the GHRH dose-response curve in patients post cranial irradiation and in controls. DESIGN: Randomized controlled study. METHODS: Five adult male long-term survivors of childhood brain tumours (median age 21.8 years (18.4-26.7); 13.7 years (11.4-15.7) post-radiotherapy, >30Gy) and five matched controls were studied. An intravenous bolus of GHRH(1-29)NH(2) was administered in doses at the lower (0.05 microg/kg) and upper (0.15 microg/kg) range of the dose-response curves for young males, as well as the standard supramaximal dose (1. 0 microg/kg). GH was measured before stimulation, every 2min for the first hour and every 5min for the second hour. All studies were conducted in a random fashion. RESULTS: Significantly lower peak and area under the curve (AUC) GH concentrations occurred in the irradiated group using 0.15 microg/kg (median peak Irradiated, 4. 5mU/l vs median Controls, 37.4mU/l; P<0.01) and 1.0 microg/kg (median peak Irradiated, 4.8mU/l vs median Controls, 15.2mU/l; P<0. 05) GHRH(1-29)NH(2). In irradiated subjects there was an incremental rise in GH output with increasing doses of GHRH(1-29)NH(2 )(median AUC: 122mU/l.min vs 179mU/l.min vs 268mU/l.min; P=0.007) reflecting altered pituitary sensitivity and reduced responsiveness. CONCLUSION: The GH response to bolus GHRH(1-29)NH(2) is attenuated in adult long-term survivors of childhood brain tumours. This may reflect direct pituitary damage and/or the loss of the tropic effects of chronic GHRH deficiency.


Asunto(s)
Hormona de Crecimiento Humana/sangre , Hormona de Crecimiento Humana/deficiencia , Traumatismos por Radiación/sangre , Sermorelina , Adolescente , Adulto , Neoplasias Encefálicas/radioterapia , Hormona de Crecimiento Humana/metabolismo , Humanos , Masculino , Valores de Referencia , Factores de Tiempo
17.
J Pediatr Endocrinol Metab ; 14(1): 3-15, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11220702

RESUMEN

Mutations in several genes have been shown to cause hypogonadotropic hypogonadism (HHG) in humans. This condition may result from abnormalities in hypothalamic gonadotropin-releasing hormone (GnRH) secretion, impaired pituitary gonadotropin release, or both. Here, we consider mutations in KAL in X-linked Kallmann syndrome; DAX1 in X-linked adrenal hypoplasia congenita; the related orphan nuclear receptor, steroidogenic factor-1; leptin and prohormone convertase-1, which may influence GnRH release and processing; the GnRH receptor; the pituitary transcription factors, HESX-1, LHX3 and PROP-1; and the gonadotropins, follicle stimulating hormone (FSH) and luteinizing hormone (LH). Identifying naturally occurring mutations in these genes provides important information about the role of these factors in the development and function of the hypothalamic-pituitary gonadal axis in humans. Different approaches to treatment and counseling may be needed, depending on the condition. Furthermore, the pathophysiological basis of HHG in the majority of individuals remains unclear, despite recent advances. Other candidate genes may be involved in these patients.


Asunto(s)
Proteínas de la Matriz Extracelular , Hipogonadismo/genética , Mutación , Proteínas Represoras , Insuficiencia Suprarrenal/genética , Receptor Nuclear Huérfano DAX-1 , Proteínas de Unión al ADN/genética , Factores de Transcripción Fushi Tarazu , Ligamiento Genético , Hormona Liberadora de Gonadotropina/genética , Hormona Liberadora de Gonadotropina/metabolismo , Gonadotropinas Hipofisarias/genética , Proteínas de Homeodominio , Humanos , Síndrome de Kallmann/genética , Proteínas del Tejido Nervioso/genética , Hormonas Hipofisarias/deficiencia , Receptores Citoplasmáticos y Nucleares , Receptores de Ácido Retinoico/genética , Factor Esteroidogénico 1 , Factores de Transcripción/genética , Cromosoma X
18.
J Pediatr Endocrinol Metab ; 14(8): 1093-6, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11592565

RESUMEN

We present a family with X-linked adrenal hypoplasia congenita (AHC) due to a truncation mutation in the DAX1 gene. The three patient reports demonstrate variable clinical and biochemical features at presentation. They presented with adrenal crises at 3 years, 4 weeks, and 3 weeks. Mineralocorticoid deficiency preceded glucocorticoid deficiency in patient 3 and an early ultrasound indicated normal sized adrenal tissue. Genetic analysis showed that potential female carriers were unaffected.


Asunto(s)
Insuficiencia Suprarrenal/diagnóstico , Insuficiencia Suprarrenal/genética , Proteínas Represoras , Cromosoma X , Glándulas Suprarrenales/diagnóstico por imagen , Insuficiencia Suprarrenal/diagnóstico por imagen , Hormona Adrenocorticotrópica/sangre , Preescolar , Receptor Nuclear Huérfano DAX-1 , Análisis Mutacional de ADN , Proteínas de Unión al ADN/genética , Ligamiento Genético , Glucocorticoides/deficiencia , Heterocigoto , Humanos , Hidrocortisona/sangre , Lactante , Recién Nacido , Masculino , Mineralocorticoides/deficiencia , Mutación , Linaje , Receptores de Ácido Retinoico/genética , Renina/sangre , Factores de Transcripción/genética , Ultrasonografía
19.
J Pediatr Urol ; 9(6 Pt A): 962-5, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23619354

RESUMEN

OBJECTIVE: Unexplained clitoromegaly is a rare but well recognised feature in girls born premature. Although detected at birth, girls may re-present during childhood to paediatric urologists and gynaecologists who should be aware of this condition. The aim of the study was to describe the clinical findings and management of a series of girls presenting with persistent congenital clitoromegaly associated with prematurity. MATERIALS AND METHODS: This was a retrospective notes review set in a tertiary referral centre for Paediatric and Adolescent Gynaecology (PAG). RESULTS: Eight girls with a mean age of 6 years were seen over an eight year period. In all cases a Disorder of Sex Development (DSD) had been previously excluded. The main symptoms were discomfort or concern about appearance. On examination five girls had excess skin over the clitoris and three had enlarged corporal tissue. Management included reassurance and simple measures to ease discomfort. In two cases the parents requested referral to a paediatric urologist to consider clitoral surgery. CONCLUSION: As survival rates for extreme prematurity improve, paediatric urologists and gynaecologists are likely to see more of these cases. Clinicians must be familiar with this condition to ensure children are managed appropriately.


Asunto(s)
Clítoris/anomalías , Trastornos del Desarrollo Sexual/etiología , Trastornos del Desarrollo Sexual/patología , Recien Nacido Prematuro , Niño , Preescolar , Clítoris/cirugía , Trastornos del Desarrollo Sexual/cirugía , Femenino , Edad Gestacional , Humanos , Recién Nacido , Estudios Retrospectivos , Centros de Atención Terciaria
20.
J Pediatr Urol ; 9(2): 139-44, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22281282

RESUMEN

OBJECTIVE: The 45,X/46,XY and 45,X/47,XYY group of patients includes some of those previously diagnosed with 'mixed gonadal dysgenesis'. Our aim was to establish the clinical and gonadal spectrum, and early surgical management, of patients with chromosomal mosaicism presenting with genital anomalies. PATIENTS AND METHODS: We performed a retrospective review of patients with 45,X/46,XY or 45,X/47,XYY mosaicism presenting with genital ambiguity between 1988 and 2009. At least one gonadal biopsy or gonadectomy specimen was available for each patient. Gonadal histology was re-evaluated by a paediatric pathologist. RESULTS: Of 31 patients with 45,X/46,XY (n = 28) or 45,X/47,XYY (n = 3) mosaicism and genital anomalies, 19 (61%) were raised male. Histology of 46 gonads was available from patients who had undergone a gonadectomy or gonadal biopsy, at a median age of 9.5 months. 18 gonads were palpable at presentation, including 5 (28%) histologically unremarkable testes, 2 streak gonads, and 1 dysgenetic gonad with distinct areas of testicular and ovarian stroma but no oocytes. All intra-abdominal gonads were found to be dysgenetic testes (of which 2 were noted to have pre-malignant changes) or streaks, apart from 1 histologically unremarkable testis. 15 (48%) patients had other anomalies, most commonly cardiac and renal; 4 (13%) had a Turner phenotype. CONCLUSION: The anatomy and gonadal histology of 45,X/46,XY and 45,X/47,XYY individuals with genital ambiguity do not conform to a set pattern, and hence management of each patient should be individualized according to detailed anatomical and histological assessment.


Asunto(s)
Disgenesia Gonadal 46 XY/patología , Disgenesia Gonadal Mixta/genética , Disgenesia Gonadal Mixta/patología , Trastornos de los Cromosomas Sexuales/genética , Trastornos de los Cromosomas Sexuales/patología , Cariotipo XYY/genética , Cariotipo XYY/patología , Preescolar , Bases de Datos Factuales , Trastornos del Desarrollo Sexual/genética , Trastornos del Desarrollo Sexual/patología , Femenino , Disgenesia Gonadal 46 XY/genética , Humanos , Lactante , Recién Nacido , Masculino , Mosaicismo , Fenotipo , Estudios Retrospectivos , Síndrome de Turner/genética , Síndrome de Turner/patología
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