Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q00604 (X-linked)
 16,883 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report on a DAX1 gene investigation in a patient with X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HH) in order to identify mutations causing this disorder and to confirm the clinical diagnosis. The description of the clinical course of the condition with a detailed documentation of longitudinal data is also reported. A male newborn was referred at 45 days of life because of vomiting, dehydration, and weight loss. The diagnosis was primary adrenal insufficiency. The appropriateness of glucocorticoid therapy during the prepubertal period was difficult to judge because of elevated ACTH levels on one hand and progressive retardation of bone age on the other hand. Basal and GnRH stimulated gonadotropin levels remained low during the entire period of examination and exogenous gonadotropin treatment was begun. This had to be interrupted at age 14.6 years because of the occurrence of a 3rd degree anaplastic ependimoma of the left posterior-parietal region, without apparent lepto-meningeal involvement. The molecular analysis of DAX1 gene of the propositus showed deletion of nucleotides AAT in exon 2, resulting in the loss of the Asn430. No alterations were found in the mother and grandmother. This deleted residue lies in one of the helices forming the hydrophobic core of the ligand-binding domain (LBD); thus this mutation may be the cause of the observed phenotype. Further investigations are needed to verify its causal role in AHC associated with HH.
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PMID:A new DAX1 gene mutation associated with congenital adrenal hypoplasia and hypogonadotropic hypogonadism. 1588 18

Mutations in the orphan nuclear receptor DAX1 (NR0B1) cause X-linked adrenal hypoplasia congenital (AHC), a disorder characterized by primary adrenal failure, hypogonadotropic hypogonadism. and azoospermia. We tested the hypothesis that DAX1 somatic mutations in human testis may cause azoospermia. DAX1 sequencing analysis in 15 testicular biopsy samples from men with idiopathic nonobstructive azoospermia did not reveal mutations in the coding region of the gene. We conclude that somatic abnormalities in DAX1 are absent or uncommon in these patients.
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PMID:Somatic mutational analysis of DAX1 in testes from men with idiopathic azoospermia. 1627 67

Mutations in the DAX1 (Dosage-sensitive sex reversal-Adrenal hypoplasia congenita (AHC) critical region on the X chromosome gene 1; NR0B1) cause X-linked AHC, a disease characterized by primary adrenal failure in infancy and hypogonadotropic hypogonadism. All known missense mutations impair DAX1 repression of steroidogenic factor 1 (SF1) transactivation and have been localized to the putative ligand binding domain. Here, an asymptomatic father and his late-onset AHC daughter were both shown to share a novel DAX1 mutation (C200W), the first missense mutation identified in the hinge region of DAX1. Using immunohistochemistry we demonstrate that the sub-cellular localization of the C200W mutant DAX1 protein is shifted from the nucleus to the cytoplasm. The disturbed localization of the C200W mutant in transfected cells correlates with impaired transcriptional repression activity. The import defect is relatively mild, retaining 80% of wild-type activity, which may explain the unusually mild phenotype. Import of DAX1 into the nucleus involves a direct interaction with SF1. In vitro assays demonstrate that the C200W mutant retains the ability to functionally interact with SF1, which suggests that SF1-independent interactions of DAX1 could be responsible for the import defect.
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PMID:A familial missense mutation in the hinge region of DAX1 associated with late-onset AHC in a prepubertal female. 1645 21

Cytomegalic adrenal hypoplasia congenita (AHC) is an X-linked disease caused by mutations in DAX1-encoding gene NR0B1, previously thought to function primarily in steroidogenesis. We sought to determine the expression pattern for Dax1 along with known network partners in early embryogenesis and to determine a steroidogenic capacity for the embryo prior to the establishment of the urogenital ridge at embryonic day 9 (E9). Here, we report that murine Dax1 is a unique marker in early embryonic development, distinguishing the extraembryonic (proximal) endoderm from the remainder of the developing embryo. We showed that Wilms tumor 1, steroidogenic factor 1, and estrogen receptor beta were expressed throughout the embryo, but the progesterone, estrogen alpha and androgen receptors, cytochrome P450 (Cyp11a1) and Nur77 were not observed in any of the embryonic layers. Lack of Cyp11A1 expression at this stage confirmed an absence of inherent steroidogenic capacity for the early embryo. The role of Nr0b1 in embryonic stem (ES) cells was investigated using siRNA knockdown, resulting in differentiation toward endoderm-like fate. Nr0b1 conditional knockout in ES cells led to differentiation, confirming our knockdown results. Our investigations suggest that Nr0b1 functions in a novel role in the maintenance of a relatively undifferentiated state. Our results further suggest that the failure of conventional murine Nr0b1 knockout attempts may be due to disregulated differentiation.
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PMID:Novel role for the orphan nuclear receptor Dax1 in embryogenesis, different from steroidogenesis. 1646 56

Mutations in the human nuclear receptor, DAX1, cause X-linked adrenal hypoplasia congenita (AHC). We report the isolation and characterization of a DAX1 homolog, dax1, in zebrafish. The dax1 cDNA encodes a protein of 264 amino acids, including the conserved carboxy-terminal ligand binding-like motif; but the amino-terminal region lacks the unusual repeats of the DNA binding-like domain in mammals. Genomic sequence analysis indicates that the dax1 gene structure is conserved also. Whole-mount in situ hybridization revealed the onset of dax1 expression in the developing hypothalamus at approximately 26 h post fertilization (hpf). Later, at about 28 hpf, a novel expression domain for dax1 appeared in the trunk. This bilateral dax1-expressing structure was located immediately above the yolk sac, between the otic vesicle and the pronephros. Interestingly, weak and transient expression of dax1 was observed in the interrenal glands (adrenal cortical equivalents) at approximately 31 hpf. This gene was also expressed in the liver after 3 dpf in the zebrafish larvae. Disruption of dax1 function by morpholino oligonucleotides (MO) down-regulated expression of steroidogenic genes, cyp11a and star, and led to severe phenotypes similar to ff1b (SF1) MO-injected embryos. Injection of dax1 MO did not affect ff1b expression, whereas ff1b MO abolished dax1 expression in the interrenal organ. Based on these results, we propose that dax1 is the mammalian DAX1 ortholog, functions downstream of ff1b in the regulatory cascades, and is required for normal development and function of the zebrafish interrenal organ.
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PMID:Zebrafish dax1 is required for development of the interrenal organ, the adrenal cortex equivalent. 1684 May 36

Hypogonadotrophic hypogonadism (HH) is characterized by delayed or absent pubertal development secondary to gonadotrophin deficiency. HH can result from mutations of the gonadotrophin-releasing hormone receptor 1, the gonadotrophin beta-subunits, or various transcription factors involved in pituitary gland development. HH occurs in DAX1 mutations when associated with adrenal insufficiency (adrenal hypoplasia congenita), and is also linked with obesity in patients with mutations of leptin and its receptor, as well as mutations in prohormone convertase 1. Rarely, HH has resulted from kisspeptin receptor (GPR54) mutations, a gene implicated in the regulation of pubertal onset. When occurring with anosmia (a lack of sense of smell), HH is referred to as Kallmann's syndrome (KS). Two KS-related loci are currently known: KAL1, encoding anosmin-1, responsible for X-linked KS, and KAL2, encoding the fibroblast growth factor receptor 1 (FGFR1), mutated in autosomal dominant KS. Anosmin-1 is an extracellular glycoprotein with some unique structural characteristics; it interacts with both urokinase-type plasminogen activator and FGFR1. It has previously been shown that anosmin-1 enhances FGFR1 signalling in a heparan sulphate-dependent manner, and proposed that anosmin-1 fine-tunes FGFR1 signalling during olfactory and GnRH neuronal development. Here, we review the known normosmic causes of HH, and discuss novel developmental and molecular mechanisms underlying KS; finally, we introduce three novel genes (NELF, PKR2, and CHD7) that may be associated with some phenotypic features of KS.
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PMID:Molecular pathogenesis of Kallmann's syndrome. 1719 Oct 30

Adrenal hypoplasia congenita (AHC) is a rare disease that can be caused by many abnormalities, including an X-linked form. Mutations in the DAX1 gene have been assigned as the genetic cause of AHC. We describe here three siblings with AHC, clinically presented at different ages, two in the neonatal period and one oligosymptomatic during infancy. Molecular analysis was able to detect a novel mutation in exon 1 of the DAX1 gene, consisting of a transition of C to T at position 359, determining a stop codon at position 359 (Q359X). The mutated gene encodes a truncated protein missing a large portion of the ligand-binding domain (C-terminal domain). The recognition of the disease in the index case suggested the diagnosis in the other siblings. Interestingly, the same mutation is presented with different phenotypes, suggesting that first-degree family members of patients with DAX1 mutations should be carefully evaluated routinely.
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PMID:A novel mutation in DAX1 gene causing different phenotypes in three siblings with adrenal hypoplasia congenita. 1757 57

The past decade has seen significant advances in our understanding of the genetic aetiology of several forms of adrenal failure that present in infancy or childhood. Several of these disorders affect adrenal development and are termed 'adrenal hypoplasia'. These conditions can be broadly divided into: (1) secondary forms of adrenal hypoplasia due to panhypopituitarism (e.g. HESX1, LHX4, SOX3) or abnormalities in ACTH synthesis (TPIT) or processing (e.g. POMC or PC1); (2) adrenal hypoplasia as part of an ACTH resistance syndrome [MC2R/ACTH receptor, MRAP, AAAS (triple A syndrome)], and (3) primary defects in the development of the adrenal gland itself (primary adrenal hypoplasia). Primary adrenal hypoplasia most commonly occurs in an X-linked form due to mutations in the nuclear receptor DAX1 (NR0B1) but can occur in a poorly understood recessive form or as part of the IMAGe (intrauterine growth retardation, metaphyseal dysplasia, adrenal hypoplasia, genitourinary anomalies) syndrome. Defining the molecular basis of these conditions can have significant clinical implications for management, counselling and presymptomatic diagnosis, as well as providing fascinating insight into normal and abnormal mechanisms of adrenal development in humans.
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PMID:Genetic disorders involving adrenal development. 1798 25

Adrenal hypoplasia congenita (AHC) is a hereditary disorder that leads to adrenal insufficiency and hypogonadotropic hypogonadism (HHG) in childhood. The gene responsible for the X-linked form of AHC, DAX1 (dosage-sensitive sex-reversal, AHC, on the X-chromosome, gene 1)/NR0B1, encodes for a nuclear factor which lacks the characteristic zinc finger DNA-binding domain that is highly conserved in nuclear receptors. Deletions and point mutations in the DAX1 gene have been described in more than 70 AHC families. We present the clinical and genetic data of two brothers affected by AHC. We report a new DAX1 gene mutation in a family with two affected members: one with neonatal adrenal insufficiency, and a sibling with adrenal hypoplasia and sudden death at 3 years old. The NR0B1/DAX1 gene was amplified in three PCR fragments from the patient's and mother's gDNA extracted from peripheral lymphocytes. Sequencing revealed a novel single nucleotide deletion in codon 419 from exon 2 that resulted in a frameshift and a stop codon 17 nucleotides downstream (c.1256 delA). The mother was heterozygous for this mutation. In conclusion, a novel DAX-1 mutation was detected in two family members with different phenotype: one live infant with adrenal hypoplasia, his mother, and probably his dead brother.
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PMID:A new DAX-1 mutation in a family with a case of neonatal adrenal insufficiency and a sibling with adrenal hypoplasia and sudden death at 3 years of age. 1803 13

Mutations of DSS (dosage sensitive sex reversal)-AHC critical region on the X chromosome, gene 1 DAX-1(NROB1)] results in X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HHG). Here we report four Japanese patients with AHC and HHG caused by the mutations of the DAX-1 gene. All patients manifested adrenal crisis at early childhood. Three patients did not show any pubertal sign and were diagnosed as having HHG. One patient manifested spontaneous pubertal development at 17 years of age. Nevertheless, his puberty did not develop further and his gonadotropin and testosterone levels decreased thereafter. Therefore, he was also diagnosed as having HHG. We performed testicular biopsy in another patient with HHG. Histological examination demonstrated Sertoli cell hypoplasia and no sperm formation in the seminiferous tubules. Molecular analysis demonstrated two novel point mutations (V269D and L278R) in two patients. Transient transfection assays showed that all these mutations (V269D, L271X, L278R, and Q395X) abolished the repression activity to both StAR and LHbeta gene promoter activation. In conclusion, we reported patients with AHC and HHG caused by the loss of function mutations of the DAX-1 gene.
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PMID:Four Japanese patients with adrenal hypoplasia congenita and hypogonadotropic hypogonadism caused by DAX-1 gene mutations: mutant DAX-1 failed to repress steroidogenic acute regulatory protein (StAR) and luteinizing hormone beta-subunit gene promoter activity. 1820 27


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