X-Linked Adrenal Hypoplasia Congenita in a Boy due to a Novel Deletion of the Entire NR0B1 (DAX1) and MAGEB1-4 Genes

Adrenal Hypoplasia: A Diagnostic and Clinical Challenge

Adrenal insufficiency can be life-threatening and results from inadequate secretion of hormones by the adrenal cortex. In pediatric patients, the most common cause is congenital adrenal hyperplasia due to 21-hydroxylase deficiency. We present a clinical case of a 17-year-old male. During the neonatal period, he experienced a salt-wasting crisis with shock, hyponatremia, metabolic acidosis, and elevated adrenocorticotropic hormone (ACTH) levels, with normal 17-hydroxyprogesterone. Hydrocortisone and fludrocortisone were initiated. Ten months later, genetic testing for the CYP21A2 gene was normal, and 17-hydroxyprogesterone levels were low, prompting the tapering of medication. However, another salt-wasting crisis led to the resumption of treatment. The patient presented a clear need for high doses of glucocorticoids to maintain symptomatic control. Genetic testing revealed a deletion in the CSNK2A1 gene, linked to Okur-Chung syndrome, along with a pathogenic NR0B1 variant, confirming adrenal hypoplasia congenita and hypogonadotropic hypogonadism. Hormone replacement and testosterone supplementation improved growth and pubertal development. The case improves our understanding of the phenotypic range and diagnostic challenges associated with NR0B1-related adrenal hypoplasia. Besides, the concurrent diagnosis of a second genetic disorder created additional challenges for both diagnoses. It emphasizes the importance of comprehensive clinical, biochemical, and genetic assessment to avoid misdiagnosis and ensure appropriate management strategies for complex endocrine disorders.

X-linked congenital adrenal hypoplasia: Report of long clinical follow-up and description of a new complex variant in the NR0B1 gene

Adrenal hypoplasia congenita, attributed to NR0B1 pathogenic variants, accounts for more than 50% of the incidence of primary adrenal insufficiency in children. Although more than 250 different deleterious variations have been described, no genotype-phenotype correlation has been defined to date. We report a case of an adopted boy who reported the onset of an adrenal crisis at 2 weeks of age, requiring replacement therapy with mineralocorticoids and glucocorticoids for 4 months. For 3 years, he did well without treatment. At almost 4 years of age, the disorder was restarted. A long follow-up showed the evolution of hypogonadotropic hypogonadism. Molecular studies on NR0B1 revealed a novel and deleterious deletion-insertion-inversion-deletion complex rearrangement sorted in the 5'-3' direction, which is described as follows: (1) deletion of the intergenic region (between TASL and NR0B1 genes) and 5' region, (2) insertion of a sequence containing 37 bp at the junction of the intergenic region of the TASL gene and a part of exon 1 of the NR0B1 gene, (3) inversion of a part of exon 1, (4) deletion of the final portion of exon 1 and exon 2 and beginning of the 3'UTR region, (5) maintenance of part of the intergenic sequence (between genes MAGEB1 and NR0B1, telomeric sense), (6) large posterior deletion, in the same sense. The path to molecular diagnosis was challenging and involved several molecular biology techniques. Evaluating the breakpoints in our patient, we assumed that it was a nonrecurrent rearrangement that had not yet been described. It may involve a repair mechanism known as nonhomologous end-joining (NHEJ), which joins two ends of DNA in an imprecise manner, generating an "information scar," represented herein by the 37 bp insertion. In addition, the local Xp21 chromosome architecture with sequences capable of modifying the DNA structure could impact the formation of complex rearrangements.

Nonsense variant of NR0B1 causes hormone disorders associated with congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is a rare X-linked recessive inherited disease that is considered a major cause of steroidogenesis disorder and is associated with variants or complete deletion of the NR0B1 gene. The DAX-1 protein (encoded by NR0B1) is a vertebrate-specific orphan nuclear receptor and is also a transcriptional factor for adrenal and reproductive development. CAH usually causes adrenal insufficiency in infancy and early childhood, leading to hypogonadotropic hypogonadism in adulthood; however, few adult cases have been reported to date. In this study, we examined a Chinese family with one adult patient with CAH, and identified a putative variant of NR0B1 gene via next-generation sequencing (NGS), which was confirmed with Sanger sequencing. A novel nonsense variant (c.265C>T) was identified in the NR0B1 gene, which caused the premature termination of DAX-1 at residue 89 (p.G89*). Furthermore, mutant NR0B1 gene displayed a partial DAX-1 function, which may explain the late pathogenesis in our case. Additionally, qPCR revealed the abnormal expression of four important genes identified from ChIP-seq, which were associated with energy homeostasis and steroidogenesis, and were influenced by the DAX-1 mutant. In addition, hormone disorders can be caused by DAX-1 mutant and partially recovered by siRNA of PPARGC1A. Herein, we identified a novel nonsense variant (c.265C>T) of NR0B1 in a 24-year-old Chinese male who was suffering from CAH. This mutant DAX-1 protein was found to have disordered energy homeostasis and steroidogenesis based on in vitro studies, which was clinically consistent with the patient’s phenotypic features.

A Novel NR0B1 Gene Mutation Causes Different Phenotypes in Two Male Patients with Congenital Adrenal Hypoplasia

X-linked congenital adrenal hypoplasia is characterised by the acute onset of primary adrenal insufficiency in infancy or early childhood and hypogonadotropic hypogonadism (HH) at puberty, arising from mutations of the nuclear receptor subfamily 0 group B member 1 (NR0B1) gene. This study investigated an extended family with two affected males (patient A: 23 years and patient B: 2 months old) and three carrier females. Sequencing analysis of the NR0B1 gene coding region from the family revealed a novel hemizygous deletion [c.604delT; p.(C202Afs*62)] in the two male patients. Furthermore, the patients' respective mothers and their common grandmother had this heterozygous mutation, but it was not present in the Human Gene Mutation Database. The two male patients showed inconsistent clinical features at onset, particularly in early childhood; however, it is possible that the younger patient will eventually show a delay of puberty, feminisation, and nonspermatogenesis in adulthood, similar to that in the older patient. Identification of a novel NR0B1 mutation in this family is important for the diagnosis and genetic counselling of children with primary adrenal insufficiency and HH, and will be helpful for predicting long-term clinical symptoms.