Gene deletion causing adrenal hypoplasia congenita and hypogonadotrophic hypogonadism

We report a patient with X-linked adrenal hypoplasia congenita and hypogonadotrophic hypogonadism in whom there were no clinical or biochemical features of either glycerol kinase deficiency or Duchenne muscular dystrophy. (The adrenal hypoplasia congenita and glycerol kinase loci map in Xp21 distal to Duchenne muscular dystrophy, and proximal to DXS727.) DNA isolated from our patient was analysed by PCR amplification with primers for appropriate loci in the Xp21 region. This analysis revealed the absence of DXS319, which lies near the adrenal hypoplasia congenita deletion critical region, and the presence of DXS727, which is distal to the gene. The absence of glycerol kinase deficiency biochemically and clinically was consistent with the presence of one glycerol kinase exon product from PCR primers P17/P18 which lies within the glycerol kinase gene. The hypogonadotrophic hypogonadism is universally found in X-linked adrenal hypoplasia congenita and is thought to be pituitary in origin. These findings suggest that a gene locus resulting in hypogonadotrophic hypogonadism is present in the Xp21 region and is an integral part of the adrenal hypoplasia congenita gene or in close relationship to it.     

Seminiferous tubule function in delayed-onset X-linked adrenal hypoplasia congenita associated with incomplete hypogonadotrophic hypogonadism

Objective X‐linked adrenal hypoplasia congenita (AHC, OMIM 300200) due to mutations in the DAX‐1 gene is frequently associated to hypogonadotrophic hypogonadism (HHG, OMIM 238320). Clinical variants with delayed‐onset have been recognized. The objective of this study is to assess Sertoli cell function throughout pubertal development in patients with childhood‐onset AHC due to stop mutations in the DAX‐1 gene. Design Observational follow‐up study of gonadotrophin pulsatility pattern, and serum levels of antimüllerian hormone and inhibin B through pubertal development in these patients. Patients Three patients belonging to two families with AHC were included in this study. Measurements The gonadotrophic pattern, serum inhibin B and antimüllerian hormone were determined in relation to clinical Tanner stage of pubertal development. Results One patient showed a marked elevation in serum FSH concomitantly with low inhibin B and antimüllerian hormone levels, indicating a primary testicular dysfunction. The other two patients showed a gonadotrophic pattern of HHG, and their serum levels of inhibin B and antimüllerian hormone also reflected a moderate primary testicular dysfunction. The three patients were azoospermic. Conclusions These cases give further insight into the clinical spectrum of phenotypes of the hypothalamic–pituitary–gonadal axis in patients with variants in hypogonadism associated with childhood‐onset X‐linked AHC due to DAX‐1 mutations.     

DAX1 and X-linked adrenal hypoplasia congenita: clinical and molecular analysis in five patients

OBJECTIVE: Mutations in the gene coding for the orphan nuclear receptor DAX1 cause X-linked adrenal hypoplasia congenita (AHC). Affected boys usually present with primary adrenal failure in early infancy or childhood. Impaired sexual development due to hypogonadotropic hypogonadism becomes manifest at the time of puberty. Moreover, evidence from Dax1 knockout mice and a limited number of patients with AHC, suggests that mutations in DAX1 may directly cause abnormalities in spermatogenesis. The aim of this study was to characterize clinically and genetically five patients with AHC. DESIGN: DNA sequencing analysis, endocrine testing, testicular ultrasound and semen analysis with 1-year follow-up after gonadotropin treatment. METHODS: We report on five men with classic AHC manifestations. Genomic DNA was extracted from patients' peripheral blood leukocytes and the coding region, splice sites, and promoter (-240 bp) region of DAX1 were directly sequenced. RESULTS: Three known and two novel mutations were detected in the DAX1 coding sequence in these patients. Semen analysis was performed in four of the five patients and showed azoospermia. Twelve-month treatment with gonadotropins did not restore fertility in these patients. All patients showed a normal testicular Doppler ultrasound, in contrast with that observed in Dax1-deficient mice, which display abnormalities in the rete testis. CONCLUSIONS: These cases further expand the number of DAX1 mutations reported in the literature, as well as our clinical knowledge of this rare disease.     

Two novel DAX1 gene mutations in Chinese patients with X-linked adrenal hypoplasia congenita: clinical, hormonal and genetic analysis

Mutations in the DAX1 gene result in X-linked congenital adrenal hypoplasia (AHC). Affected boys usually present with primary adrenal failure in early infancy or childhood and hypogonadotropic hypogonadism (HH) at puberty. This paper describes the clinical, hormonal, radiological, and genetic characteristics of 2 Chinese patients with X-linked AHC. Primary adrenal insufficiency occurred in the 2 patients during their childhood and HH was recognized at puberty. Genomic DNA was extracted from their peripheral blood leukocytes and coding sequence abnormalities of the DAX1 gene were assessed by PCR and direct sequencing analysis. Genetic analysis of the DAX1 gene revealed 2 novel mutations c.572-575 dupGGGC, p.Thr193Gly,fs,205X and c.773- 774 dupCC, p.Ser259Pro,fs,264X in exon 1, causing frameshifts and yeilding premature stop codons at 205 and 264, respectively. This study identifies 2 novel mutations in the DAX1 gene which can further expand the mutation database and benefit patients in the diagnosis and treatment of AHC.     

X-linked adrenal hypoplasia congenita: a mutation in DAX1 expands the phenotypic spectrum in males and females

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.     

Hypogonadotropic hypogonadism as a presenting feature of late-onset X-linked adrenal hypoplasia congenita.

Mutations in the orphan nuclear receptor DAX-1 cause X-linked adrenal hypoplasia congenita. Affected boys usually present with primary adrenal failure in early infancy or childhood. Impaired sexual development because of hypogonadotropic hypogonadism becomes apparent at the time of puberty. We report adult-onset adrenal hypoplasia congenita in a patient who presented with hypogonadism at 28 yr of age. Although he had no clinical evidence of adrenal dysfunction, compensated primary adrenal failure was diagnosed by biochemical testing. Semen analysis showed azoospermia, and he did not achieve fertility after 8 months of treatment with gonadotropins. A novel Y380D DAX-1 missense mutation, which causes partial loss of function in transient gene expression assays, was found in this patient. This case demonstrates that partial loss-of-function mutations in DAX1 can present with hypogonadotropic hypogonadism and covert adrenal failure in adulthood. Further, an important role for DAX-1 in spermatogenesis in humans is confirmed, supporting findings in the Dax1 (Ahch) knockout mouse.     

Adrenocorticotropin-dependent precocious puberty of testicular origin in a boy with X-linked adrenal hypoplasia congenita due to a novel mutation in the DAX1 gene.

Primary adrenal insufficiency is a rare condition in pediatric age, and its association with precocious sexual development is very uncommon. We report a 2-yr-old Brazilian boy with DAX1 gene mutation whose first clinical manifestation was isosexual gonadotropin-independent precocious puberty. He presented with pubic hair, enlarged penis and testes, and advanced bone age. T levels were elevated, whereas basal and GnRH-stimulated LH levels were compatible with a prepubertal pattern. Chronic GnRH agonist therapy did not reduce T levels, supporting the diagnosis of gonadotropin-independent precocious puberty. Testotoxicosis was ruled out after normal sequencing of exon 11 of the LH receptor gene. At age 3 yr he developed clinical and hormonal features of severe primary adrenal insufficiency. The entire coding region of the DAX1 gene was analyzed through direct sequencing. A nucleotide G insertion between nucleotides 430 and 431 in exon 1, resulting in a novel frameshift mutation and a premature stop codon at position 71 of DAX-1, was identified. Surprisingly, steroid replacement therapy induced a clear decrease in testicular size and T levels to the prepubertal range. These findings suggest that chronic excessive ACTH levels resulting from adrenal insufficiency may stimulate Leydig cells and lead to gonadotropin-independent precocious puberty in some boys with DAX1 gene mutations.     

Prolonged activation of the hypothalamus-pituitary-gonadal axis in a child with X-linked adrenal hypoplasia congenita

X-linked adrenal hypoplasia congenita (AHC) is a rare developmental disorder of the human adrenal cortex that is caused by a mutation of the DAX-1 gene, a member of the nuclear hormone receptor superfamily. Hypogonadotrophic hypogonadism is frequently associated with this disease and the DAX-1 mutation is known to impair gonadotrophin production by acting at both the hypothalamic and pituitary levels. However, three recent studies reported that the hypothalamic-pituitary-gonadal axis was active in six infants with AHC, suggesting that a difference exists in the central regulation of hypothalamic-pituitary-gonadal activity between infant boys and pubertal boys. To determine the effect of the DAX-1 gene mutation on the axis in early childhood, we measured testosterone, LH, and FSH and performed LH-releasing hormone tests on a boy with AHC from birth to 3 years of age. Surprisingly, our findings showed that the axis was active from the infantile period to 3 years of age. This delayed initiation of the prepubertal pause, or prolonged activation of the axis, indicates that the DAX-1 gene is related to the control mechanism of the prepubertal restraint of gonadotrophin secretion.     

X-linked congenital adrenal hypoplasia: new mutations and long-term follow-up in three patients

Mutations of the DAX-1 gene, which encodes a newly discovered member of the nuclear hormone receptor family, were reported to cause X-linked congenital adrenal hypoplasia and hypogonadotrophic hypogonadism. While genetic data on DAX-1 are accumulating, information on the clinical course of the disorder are scarce. Here we present a detailed documentation of longitudinal data relating to three cases. We retrospectively collected clinical data on three boys (6, 14 and 14.5 years old) who we examined over a period ranging between 5 and 14 years. Mutational analysis of the DAX-1 gene was performed by means of direct sequencing of PCR products. The patients presented at ages between 4 and 6 weeks with salt-wasting, but there was no evidence of hypoglycaemia. All three cases were initially erroneously diagnosed with isolated aldosterone deficiency. Glucocorticoid deficiency was established by means of ACTH stimulation tests at 4 months, 3 and 13 years of age. One boy, whose therapy was discontinued at the age of 4 months, developed normally until adrenal crisis occurred at the age of 13 years. In all three cases, congenital hypogonadism was ruled out during infancy, as penis size was normal, the testes were descended, and serum samples contained normal testosterone levels. One boy exhibited transient hypergonadotrophism at age 9 but showed no clinical signs of puberty or an increase in serum testosterone. Onset of puberty and LHRH tests proved to be normal in his case as well as in another patient studied. In two patients, genetic analysis revealed new mutations at the C-terminus of DAX-1, these being a 1-base deletion (656delG) inherited from the mother and a de-novo 2-base insertion (728insCA) of the DAX-1 gene, respectively, both causing frame shift and premature stops at codons 263 and 398. One boy was affected by a new nonsense mutation of codon 39 (W39X) inherited from his mother. Mineralocorticoid deficiency preceded glucocorticoid deficiency which could be diagnosed through ACTH stimulation after the neonatal period. Transitory functional recovery of the adrenal glands can occur in adrenal hypoplasia congenita (AHC). Transient hypergonadotrophism may be one of the first indicators of defects in the gonadal axis, although normal initiation of puberty is not rare. The definitive diagnosis was established by means of molecular analysis of the DAX-1 gene. There was no correlation between types of mutations and phenotypes. The diagnostic procedure in male children and adolescents presenting with adrenal crisis should include ACTH stimulation tests and mutational analysis of DAX-1 in the absence of another proven aetiology.     

Congenital adrenal hypoplasia and DAX-1 gene mutations

DAX-1 is a member of the orphan nuclear hormone receptor family. Its mutations cause X-linked adrenal hypoplasia congenita, a disease characterized by adrenal insufficiency due to impaired organogenesis of the adrenal cortex and hypogonadotrophic hypogonadism. We review herein the pathologic and clinical features of the disease and describe some recent advances in the clinical expression of X-linked adrenal hypoplasia congenita.