RESUMEN
STUDY QUESTION: Is the 24-h urinary gonadotropin assay an effective diagnostic tool in central precocious puberty (CPP) in girls? SUMMARY ANSWER: This study is the first to provide 24-h urinary gonadotropin assay data, using an electrochemiluminescent immunoassay (CMIA), and to report its usefulness as a tool for the diagnosis of CPP. WHAT IS KNOWN ALREADY: Data about the GnRH test in the diagnosis of CPP are variable and there is no consensus regarding its interpretation. The measurement of FSH and LH in urines was previously reported to be an alternative biological tool. STUDY DESIGN, SIZE, DURATION: This is a retrospective two-cohort study, involving a setting and a validation cohort. A total of 516 girls, included between October 2012 and July 2015, and 632 urinary collections were analyzed in the setting cohort. In the validation cohort, 39 girls were included between January 2021 and May 2023, and 49 urinary collections were analyzed. PARTICIPANTS/MATERIALS, SETTING, METHODS: This study included girls who consulted for an investigation of disturbed growth rate or a clinical suspicion of puberty onset in different medical centres across France (setting cohort). Girls with a suspicion of precocious puberty onset were addressed at the expert centre of paediatric endocrinology of the Groupement Hospitalier Lyon Est (validation cohort). Pelvic ultrasonography was performed and enabled their classification according to clinical and morphologic changes criteria (prepubertal or pubertal groups). The parents collected 24-h urine samples (u24) according to standardized instructions. FSH and LH (urinary or plasmatic) were measured using a current and automated CMIA. MAIN RESULTS AND THE ROLE OF CHANCE: The area under the ROC curves for CPP prediction was 0.709 for u24FSH (P < 0.001), 0.767 for u24LH (P < 0.001), and 0.753 for the u24LH/u24FSH ratio (P < 0.001). We retained all possible combinations of the four thresholds in the validation cohort (u24FSH = 1.1 or 2.0 IU/24 h; u24LH = 0.035 or 0.08 IU/24 h). The combination of u24FSH > 1.1 IU/24 h and u24LH > 0.08 IU/24 h had a positive PV of 85.7% and a negative PV of 94.3%, a sensitivity of 85.7% and a specificity of 94.3%, for classifying prepubertal and pubertal girls in this cohort. LIMITATIONS, REASONS FOR CAUTION: This is a retrospective study, in which a margin of error remains due to the inherent uncertainty regarding the clinical assessment of pubertal onset. It must be considered that the thresholds can only apply to the used reagents; measurements without extractions using other reagents are likely to show important heterogeneity. WIDER IMPLICATIONS OF THE FINDINGS: The assay performed herein is a simple, non-invasive, and analytically robust technique meeting the criteria for an alternative to the GnRH test which could be used to supplement its lack of sensitivity. STUDY FUNDING/COMPETING INTEREST(S): No specific funding was used. All authors declared no conflict of interest. TRIAL REGISTRATION NUMBER: In-house #23-5214 registered study.
Asunto(s)
Hormona Folículo Estimulante , Hormona Luteinizante , Pubertad Precoz , Humanos , Femenino , Pubertad Precoz/orina , Pubertad Precoz/diagnóstico , Pubertad Precoz/sangre , Estudios Retrospectivos , Niño , Hormona Luteinizante/sangre , Hormona Luteinizante/orina , Hormona Folículo Estimulante/sangre , Hormona Folículo Estimulante/orina , Inmunoensayo/métodos , Valor Predictivo de las PruebasRESUMEN
Background: Steroidogenic factor 1 (SF-1), encoded by the nuclear receptor subfamily 5 group A member 1 (NR5A1) gene, is a transcriptional factor crucial for adrenal and gonadal organogenesis. Pathogenic variants of NR5A1 are responsible for a wide spectrum of phenotypes with autosomal dominant inheritance including disorders of sex development and oligospermia-azoospermia in 46,XY adults. Preservation of fertility remains challenging in these patients. Objective: The aim was to offer fertility preservation at the end of puberty in an NR5A1 mutated patient. Case report: The patient was born of non-consanguineous parents, with a disorder of sex development, a small genital bud, perineal hypospadias, and gonads in the left labioscrotal fold and the right inguinal region. Neither uterus nor vagina was detected. The karyotype was 46,XY. Anti-Müllerian hormone (AMH) and testosterone levels were low, indicating testicular dysgenesis. The child was raised as a boy. At 9 years old, he presented with precocious puberty treated by triptorelin. At puberty, follicle-stimulating hormone (FSH), luteinising hormone (LH), and testosterone levels increased, whereas AMH, inhibin B, and testicular volume were low, suggesting an impaired Sertoli cell function and a partially preserved Leydig cell function. A genetic study performed at almost 15 years old identified the new frameshift variant NM_004959.5: c.207del p.(Phe70Serfs*5) at a heterozygous state. He was thus addressed for fertility preservation. No sperm cells could be retrieved from three semen collections between the ages of 16 years 4 months and 16 years 10 months. A conventional bilateral testicular biopsy and testicular sperm extraction were performed at 17 years 10 months of age, but no sperm cells were found. Histological analysis revealed an aspect of mosaicism with seminiferous tubules that were either atrophic, with Sertoli cells only, or presenting an arrest of spermatogenesis at the spermatocyte stage. Conclusion: We report a case with a new NR5A1 variant. The fertility preservation protocol proposed at the end of puberty did not allow any sperm retrieval for future parenthood.
Asunto(s)
Maduración Sexual , Testosterona , Masculino , Hormona Antimülleriana , Estudios de Seguimiento , Factor Esteroidogénico 1/genética , Testículo , Humanos , Niño , AdolescenteRESUMEN
OBJECTIVES: Elevated free T3 (FT3) is an important feature for the early diagnosis of several diseases among which Grave's disease or Allan-Hernon-Dudley syndrome. However, there is a lack of age-adapted reference intervals for plasma thyroid hormones in children. We conducted a study to define reference values of peripheral FT3 in children using a commonly used automated immunoassay. METHODS: All thyroid function test (TFT) results from our lab collected during 9 months were extracted anonymously, and reference intervals establishment followed recommendations validated by International Federation of Clinical Chemistry (IFCC). RESULTS: We defined five reference intervals covering the whole pediatric period. Overall, 26.1% of peripheral FT3 measured in children with normal TSH are out of the adult reference range, and 22.2% are upper it leading to misinterpretation. In a 9-month old patient with severe neurodevelopmental disorders, a pathological elevated FT3 has been securely interpreted using the newly established interval. CONCLUSIONS: The study highlights the poor relevance of adult intervals in pediatric cares, as it confirms that plasmatic FT3 is higher during the whole pediatric period. This work reports useful age-adapted reference intervals for free T3 in pediatrics using a widely used electrochemiluminescent Immunoassay (ECLIA) kit.
Asunto(s)
Pruebas de Función de la Tiroides , Triyodotironina , Adulto , Humanos , Niño , Lactante , Pruebas de Función de la Tiroides/métodos , Tiroxina , Tirotropina , Hormonas Tiroideas , Valores de ReferenciaRESUMEN
Objectives: To examine the changes in diagnostic practices and clinical management of patients with 5α-reductase type 2 (SRD5A2) or 17ß-hydroxysteroid dehydrogenase type 3 (HSD17B3) deficiency since molecular diagnoses became available. Methods: Clinical, laboratory, and therapeutic data were retrieved from the medical records of 52 patients with a molecular diagnosis of SRD5A2 (n = 31) or HSD17B3 (n = 21) deficiency. Temporal trends regarding age at assessment and initial sex assignment over 1994-2020 were qualitatively analyzed. Age at molecular diagnosis was compared between two subgroups of patients according to their year of birth. Results: Fifty-eight percent (n = 30) patients were diagnosed during the perinatal period, 33% (n = 17) during infancy, and 9% (n = 5) during adolescence or adulthood. Over the studied period, the patients' age at initial assessment and diagnosis frankly decreased. The median (range) age at diagnostic confirmation was 10.5 (0-53.2) years for patients born before 2007 and 0.4 (0-9.3) years for those born in 2007 or later (P = 0.029). Genetic testing identified 27 different variants for the SRD5A2 gene (30% novel, n = 8) and 18 for the HSD17B3 gene (44% novel, n = 8). Before 2002, most patients were initially assigned as females (95%, n = 19), but this proportion dropped for those born later (44%, n = 14; P < 0.001). The influence of initial genital appearance on these decisions seemingly decreased in the most recent years. Therapeutic interventions differed according to the sex of rearing. Ten percent (n = 2) patients requested female-to-male reassignment during adulthood. Conclusion: This study showed, over the past two decades, a clear trend toward earlier diagnosis and assignment of affected newborns as males.
RESUMEN
Design: Thyroid-stimulating hormone deficiency (TSHD) is a rare disease. It may be isolated, secondary to abnormalities of genes involved in TSH biosynthesis, or associated with other pituitary deficits or abnormalities of genes involved in pituitary ontogenesis. Several genes are involved in thyrotroph development and function. Objective: Our aim was to determine the genetic causes of TSHD, either isolated (ITSHD) or associated with somatotroph deficiency (TSHD-GHD), in the cohort of patients from the GENHYPOPIT network. Methods: Next-generation sequencing (NGS) analyses were performed as a panel of genes on a cohort of patients with non-syndromic ITSHD or TSHGHD. The variants were classified according to the American College of Medical Genetics classification reviewed by the NGS-Diag network and correlated with the phenotype. Class 3, 4, and 5 single-nucleotide variants were checked by Sanger sequencing and copy number variants by multiplex ligation-dependent probe amplification (MLPA). Results: A total of 64 index cases (22 ITSHD and 42 TSHD-GHD) were included in this cohort. A genetic cause was identified in 26.5% of patients, with 36.3% in the ITSHD group (variants in TSHß and IGSF1) and 21.4% in TSHD-GHD (variants in IGSF1, TSHß, TRHR, GH1, POU1F1, and PROP1). Among the pathogenic and likely pathogenic variants identified, 42% were in IGSF1, including six not previously reported. Conclusion: Our results show that IGSF1 variants represent the most frequent aetiology of TSH deficiency. Despite a systematic NGS approach and the identification of new variants, most patients remain without a molecular diagnosis. Larger scale studies, such as exome or genome studies, should be considered in the future.
Asunto(s)
Hipotiroidismo , Enfermedades de la Hipófisis , Humanos , Hipotiroidismo/genética , Mutación/genética , Secuenciación del Exoma , Tirotropina , Inmunoglobulinas/genética , Proteínas de la Membrana/genéticaRESUMEN
Turner syndrome (TS; ORPHA 881) is a rare condition in which all or part of one X chromosome is absent from some or all cells. It affects approximately one in every 1/2500 liveborn girls. The most frequently observed karyotypes are 45,X (40-50%) and the 45,X/46,XX mosaic karyotype (15-25%). Karyotypes with an X isochromosome (45,X/46,isoXq or 45,X/46,isoXp), a Y chromosome, X ring chromosome or deletions of the X chromosome are less frequent. The objective of the French National Diagnosis and Care Protocol (PNDS; Protocole National de Diagnostic et de Soins) is to provide health professionals with information about the optimal management and care for patients, based on a critical literature review and multidisciplinary expert consensus. The PNDS, written by members of the French National Reference Center for Rare Growth and Developmental Endocrine disorders, is available from the French Health Authority website. Turner Syndrome is associated with several phenotypic conditions and a higher risk of comorbidity. The most frequently reported features are growth retardation with short adult stature and gonadal dysgenesis. TS may be associated with various congenital (heart and kidney) or acquired diseases (autoimmune thyroid disease, celiac disease, hearing loss, overweight/obesity, glucose intolerance/type 2 diabetes, dyslipidemia, cardiovascular complications and liver dysfunction). Most of the clinical traits of TS are due to the haploinsufficiency of various genes on the X chromosome, particularly those in the pseudoautosomal regions (PAR 1 and PAR 2), which normally escape the physiological process of X inactivation, although other regions may also be implicated. The management of patients with TS requires collaboration between several healthcare providers. The attending physician, in collaboration with the national care network, will ensure that the patient receives optimal care through regular follow-up and screening. The various elements of this PNDS are designed to provide such support.
Asunto(s)
Diabetes Mellitus Tipo 2 , Síndrome de Turner , Adulto , Cromosomas Humanos X/genética , Femenino , Humanos , Cariotipo , Cariotipificación , Síndrome de Turner/diagnóstico , Síndrome de Turner/genética , Síndrome de Turner/terapiaRESUMEN
INTRODUCTION: Maternal TSH receptor antibodies (TRAbs) can cross the placenta and affect fetal and neonatal thyroid function. Maternal TSH receptor-blocking antibodies (TBAbs) are a rare cause of congenital hypothyroidism. CASE REPORT: Following the discovery of a highly elevated TSH on her neonatal screening test, a 10-day-old girl with no familial history of thyroid disorder was referred to the pediatric endocrinology unit. Hypothyroidism was confirmed with a highly elevated TSH (817 mIU/L, reference range 0.4-3.1) and very low levels of FT4 (1.8 pmol/L, reference range 12-22). Anti-TPO antibodies were at 81 IU/mL (reference range <34), TRAbs at 1.7 IU/L (reference range <1.75), and thyroglobulin at 9.4 µg/L (reference range 3.5-77). The thyroid appeared normal on ultrasonography, and no radioiodine uptake was seen on the scintigraphy after the perchlorate discharge test. Concomitantly, a severe maternal hypothyroidism was discovered (TSH 224 mIU/L). The maternal ultrasound appeared normal, anti-TPO antibodies were moderately elevated, and TRAbs were at 3.2 IU/L. TBAbs activity was measured in the mother and her daughter, and a very high and similar blocking activity was observed in both patients (TBAbs 89%, reference range <10%). L-thyroxine treatment was introduced in the newborn and was successfully discontinued at 6.5 months of age, as the TBAbs activity decreased. CONCLUSION: We report herein a case of transient congenital hypothyroidism with a normal neonatal TRAbs level. In case of maternal TBAbs, similar activity of maternal TBAbs must be expected in the neonate, independently of the neonatal level of TRAbs.
RESUMEN
Context: MIRAGE (Myelodysplasia, Infection, Restriction of growth, Adrenal hypoplasia, Genital phenotypes, Enteropathy) syndrome is a severe multisystem disorder with high mortality. It is caused by a heterozygous gain of function mutation in the growth repressor gene SAMD9. The increasing number of reported cases displays a spectrum of phenotypes that may be explained by an adaptation mechanism, with appearance of a somatic second hit mutation with revertant effects. Objective: To determine the genetic basis of the MIRAGE syndrome rapidly corrected in a living and healthy 46,XY patient. Subjects and Methods: A 46,XY patient born with growth restriction and disorders of sex development had thrombocytopenia and necrotizing enterocolitis during the neonatal period suggestive of the syndrome. Faced with the rapid improvement of the patient's phenotype, an adaptation mechanism was sought by repeating genetic analysis at different ages; her parents also underwent genetic analysis. Results: The previously described p.(Thr778Ile) mutation was identified and surprisingly transmitted by the asymptomatic mother in this usually de novo syndrome. To explain the rapid improvement of the patient's phenotype and absence of symptoms in the mother, an adaptation mechanism was sought. For the mother, a non-sense mutation was found (p.(Arg221*)) in cis, and most likely appeared in utero. It was not transmitted to her child. The child harbored a different non-sense mutation (p.(Arg285*)) that most likely appeared near day 20. Conclusions: We show that pathogenic variants can be inherited from a healthy parent as the adaptation mechanism may arise early in life and mask symptoms. Presence of revertant mosaicism mutations could explain "incomplete penetrance" in other disease. For a better management and outcomes in patients, appearance of this natural gene therapy should be sought by repeating genetic analysis.
RESUMEN
BACKGROUND: In congenital adrenal hyperplasia (CAH), adjusting hydrocortisone dose during childhood avoids reduced adult height. However, there are currently no CAH-specific charts to monitor growth during treatment. Our objective was to elaborate growth reference charts and bone maturation data for CAH patients. METHODS: We conducted a retrospective observational cohort study, in 34 French CAH centers. Patients were 496 children born 1970-1991 with genetically proven 21-hydroxylase deficiency. Their growth and bone maturation data were collected until age 18 together with adult height, puberty onset, parental height, and treatment. The mean (SD) heights were modeled from birth to adulthood. The median±1 SD and ±2 SDs model-generated curves were compared with the French references. A linear model for bone maturation and a logistic regression model for the probability of short adult height were built. RESULTS: Growth charts were built by sex for salt wasting (SW) and simple virilizing (SV) children treated before 1 year of age. In girls and boys, growth was close to that of the general French population up to puberty onset. There was almost no pubertal spurt and the mean adult height was shorter than that of the general population in girls (-1.2 SD, 156.7 cm) and boys (-1.0 SD, 168.8 cm). Advanced bone age at 8 years had a strong impact on the risk of short adult height (OR: 4.5 per year advance). CONCLUSIONS: The 8-year bone age is a strong predictor of adult height. It will help monitoring the growth of CAH-affected children.
Asunto(s)
Hiperplasia Suprarrenal Congénita/fisiopatología , Estatura/fisiología , Gráficos de Crecimiento , Maduración Sexual/fisiología , Adolescente , Adulto , Desarrollo Óseo , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Lactante , Recién Nacido , Masculino , Estudios Retrospectivos , Adulto JovenRESUMEN
BACKGROUND: Deficient nucleotide excision repair (NER) activity causes a variety of autosomal recessive diseases including xeroderma pigmentosum (XP) a disorder which pre-disposes to skin cancer, and the severe multisystem condition known as Cockayne syndrome (CS). In view of the clinical overlap between NER-related disorders, as well as the existence of multiple phenotypes and the numerous genes involved, we developed a new diagnostic approach based on the enrichment of 16 NER-related genes by multiplex amplification coupled with next-generation sequencing (NGS). METHODS: Our test cohort consisted of 11 DNA samples, all with known mutations and/or non pathogenic SNPs in two of the tested genes. We then used the same technique to analyse samples from a prospective cohort of 40 patients. Multiplex amplification and sequencing were performed using AmpliSeq protocol on the Ion Torrent PGM (Life Technologies). RESULTS: We identified causative mutations in 17 out of the 40 patients (43%). Four patients showed biallelic mutations in the ERCC6(CSB) gene, five in the ERCC8(CSA) gene: most of them had classical CS features but some had very mild and incomplete phenotypes. A small cohort of 4 unrelated classic XP patients from the Basque country (Northern Spain) revealed a common splicing mutation in POLH (XP-variant), demonstrating a new founder effect in this population. Interestingly, our results also found ERCC2(XPD), ERCC3(XPB) or ERCC5(XPG) mutations in two cases of UV-sensitive syndrome and in two cases with mixed XP/CS phenotypes. CONCLUSIONS: Our study confirms that NGS is an efficient technique for the analysis of NER-related disorders on a molecular level. It is particularly useful for phenotypes with combined features or unusually mild symptoms. Targeted NGS used in conjunction with DNA repair functional tests and precise clinical evaluation permits rapid and cost-effective diagnosis in patients with NER-defects.
Asunto(s)
Reparación del ADN/genética , Síndrome de Cockayne/genética , ADN Helicasas/genética , Enzimas Reparadoras del ADN/genética , Proteínas de Unión al ADN/genética , ADN Polimerasa Dirigida por ADN/genética , Endonucleasas/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Mutación , Proteínas Nucleares/genética , Fenotipo , Proteínas de Unión a Poli-ADP-Ribosa , Factores de Transcripción/genética , Proteína de la Xerodermia Pigmentosa del Grupo D/genéticaRESUMEN
CONTEXT: Hyperthyroidism occurs in 1% of neonates born to mothers with active or past Graves' disease (GD). Current guidelines for the management of GD during pregnancy were based on studies conducted with first-generation thyroid-binding inhibitory immunoglobulin (TBII) assays. OBJECTIVE: This retrospective study was conducted in order to specify the second-generation TBII threshold predictive of fetal and neonatal hyperthyroidism, and to identify other factors that may be helpful in predicting neonatal hyperthyroidism. METHODS: We included 47 neonates born in the Lyon area to 42 mothers harboring measurable levels of TBII during pregnancy. TBII measurements were carried out in all mothers; bioassays were carried out in 20 cases. RESULTS: Nine neonates were born with hyperthyroidism, including five with severe hyperthyroidism requiring treatment. Three neonates were born with hypothyroidism. All hyperthyroid neonates were born to mothers with TBII levels >5âIU/l in the second trimester (sensitivity, 100% and specificity, 43%). No mother with TSH receptor-stimulating antibodies (TSAb measured by bioassay) below 400% gave birth to a hyperthyroid neonate. Among mothers of hyperthyroid neonates, who required antithyroid drugs during pregnancy, none could stop treatment before delivery. Analysis of TBII evolution showed six unexpected cases of increasing TBII values during pregnancy. CONCLUSION: Maternal TBII value over 5âIU/l indicates a risk of neonatal hyperthyroidism. Among these mothers, a TSAb measurement contributes to identify more specifically those who require a close fetal thyroid ultrasound follow-up. These results should be confirmed in a larger series.
Asunto(s)
Enfermedad de Graves/inmunología , Inmunoglobulinas Estimulantes de la Tiroides/sangre , Enfermedades del Recién Nacido/inmunología , Complicaciones del Embarazo/inmunología , Efectos Tardíos de la Exposición Prenatal/inmunología , Glándula Tiroides/inmunología , Adulto , Biomarcadores/sangre , Femenino , Francia , Humanos , Recién Nacido , Masculino , Valor Predictivo de las Pruebas , Embarazo , Estudios RetrospectivosRESUMEN
OBJECTIVE: To describe the action of prenatal dexamethasone (PreDex) on the anatomy of female congenital adrenal hyperplasia (CAH) genitalia when started at later stages of gestation. MATERIALS AND METHODS: Our group follows a large cohort of French CAH patients who underwent PreDex therapy, of whom 258 were recently reported. Four 46,XX patients with a delayed PreDex treatment presented with a virilized genitalia and required surgical reconstruction. This is a retrospective report on genital phenotyping at the time of surgery of these four patients who began PreDex therapy at 8, 12, 20, and 28 weeks of gestation. RESULTS: Although this series is limited in number, the anatomical description of the length of the genital tubercle, the height of the urethra-vaginal confluence, and the degree of fusion of the genital folds seems to be dependent upon the starting date of PreDex. Most PreDex treatments prescribed up to now have covered the full duration of gestation. CONCLUSIONS: Our findings suggest that PreDex therapy could be limited to the period of the partitioning window. It is hoped that further prospective multicentric clinical studies will obtain ethical approval in order to elucidate the place and protocols of PreDex therapy in the management of CAH.
Asunto(s)
Hiperplasia Suprarrenal Congénita/tratamiento farmacológico , Hiperplasia Suprarrenal Congénita/cirugía , Dexametasona/administración & dosificación , Glucocorticoides/administración & dosificación , Virilismo/tratamiento farmacológico , Virilismo/cirugía , Hiperplasia Suprarrenal Congénita/patología , Esquema de Medicación , Femenino , Terapias Fetales , Edad Gestacional , Humanos , Lactante , Fenotipo , Embarazo , Estudios Retrospectivos , Virilismo/etiologíaRESUMEN
Kallmann syndrome characterised by hypogonadotropic hypogonadism (HH) and anosmia is genetically heterogeneous with X-linked, autosomal dominant and autosomal recessive forms. The autosomal dominant form due to loss of function mutation in the fibroblast growth factor receptor 1 (FGFR1) accounts for about 10% of cases. We report here three paediatric cases of Kallmann syndrome with unusual phenotype in two unrelated patients with severe ear anomalies (hypoplasia or agenesis of external ear) associated with classical features, such as cleft palate, dental agenesis, syndactylia, micropenis and cryptorchidism. We found de novo mutation in these two patients (Cys178Ser and Arg622Gly, respectively), and one inherited Arg622Gln mutation with intrafamilial variable phenotype. These genotype-phenotype correlations indicate that paediatric phenotypic expression of FGFR1 loss of function mutations is highly variable, the severity of the oro-facial malformations at birth does not predict gonadotropic function at the puberty and that de novo mutations of FGFR1 are relatively frequent.
Asunto(s)
Síndrome de Kallmann/genética , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/genética , Adolescente , Fisura del Paladar/genética , Criptorquidismo/genética , Análisis Mutacional de ADN , Sordera/congénito , Hipoplasia del Esmalte Dental/genética , Hormona Folículo Estimulante/sangre , Genitales Masculinos/anomalías , Humanos , Lactante , Cariotipificación , Hormona Luteinizante/sangre , Masculino , Mutación , Trastornos del Olfato/congénito , Bulbo Olfatorio/anomalías , Linaje , Fenotipo , Pubertad Tardía/genética , Sindactilia/genética , Sincinesia/congénito , Testosterona/sangreRESUMEN
Targeted disruption of the orphan nuclear receptor SF1 results in the absence of adrenals and gonads, establishing that this transcription factor is implicated in gonadal determination and adrenal development. Four human SF1 gene mutations have been described to date: three (G35E, R92Q, R255L) were responsible for adrenal insufficiency associated with a gonadal dysgenesis in two 46, XY individuals, one (8 bp deletion in exon 6) resulted in gonadal dysgenesis without adrenal insufficiency. We identified a new heterozygous SF1 gene mutation, C16X, in a 46, XY patient showing gonadal dysgenesis with normal adrenal function: low basal levels of AMH and testosterone (T), weak T response to hCG, hypoplastic testes with abundant seminiferous tubules but rare germ cells. This mutation causes premature termination of translation and should abolish all SF1 activity. Therefore haploinsufficiency could explain the deleterious effect of this mutation in our patient suggesting that testis development is more SF1 dose-dependent than adrenal development. Although the same mechanism explains the deleterious effects of SF1 missense mutations, recent studies have demonstrated an additional dominant negative effect. These data suggest that heterozygous mutation impaired adrenal development only if the two mechanisms, gene dosage and dominant negative effects occur.