X-linked adrenal hypoplasia congenita: clinical and follow-up findings of two kindreds, one with a novel NR0B1 mutation

Case Report: A Novel Truncating Variant of NR0B1 Presented With X-Linked Late-Onset Adrenal Hypoplasia Congenita With Hypogonadotropic Hypogonadism

Nuclear receptor subfamily 0 group B member 1 gene (NR0B1) encodes an orphan nuclear receptor that plays a critical role in the development and regulation of the adrenal gland and hypothalamic-pituitary-gonadal axis. In this study, we report a novel mutation in NR0B1 that led to adult-onset adrenal hypoplasia congenita (AHC) and pubertal development failure in a male adult. Clinical examinations revealed hyponatremia, elevated adrenocorticotropic hormone levels, reduced testosterone and gonadotropin levels, and hyper-responses to gonadotropin-releasing hormone and human chorionic gonadotropin stimulation tests. Whole-exome sequencing and Sanger sequencing were performed to identify the potential causes of AHC. Candidate variants were shortlisted based on the X-linked recessive models. Sequence analyses identified a novel hemizygous variant of c.1034delC in exon 1 of NR0B1 at Xp21.2, resulting in a frameshift mutation and premature stop codon formation. The c.1034delC/p.Pro345Argfs*27 in the NR0B1 gene was detected in the hemizygous state in affected males and in the heterozygous state in healthy female family carriers. These results expand the clinical features of AHC as well as the mutation profile of the causative gene NR0B1. Further studies are needed to elucidate the biological effects of the mutation on the development and function of the adrenal gland and the hypothalamic-pituitary-gonadal axis.

X-linked congenital adrenal hypoplasia: a case presentation

BACKGROUND

Most patients with congenital adrenal hypoplasia (AHC) develop symptoms during infantile and juvenile periods, with varying clinical manifestations. AHC is a disease that is easily misdiagnosed as Addison's disease or congenital adrenal hyperplasia (CAH). There was also a significant time difference between the age at which patients developed symptoms and the age at which they were diagnosed with AHC. Most patients showed early symptoms during infantile and juvenile periods, but were diagnosed with AHC many years later.

CASE PRESENTATION

We are currently reporting a male patient who developed systemic pigmentation at age 2 and was initially diagnosed with Addison's disease. At 22 years of age, he experienced a slipped capital femoral epiphysis (SCFE), a disease mostly seen in adolescents aged 8-15 years, an important cause of which is endocrine disorder. Testes evaluated using color Doppler Ultrasonography suggested microcalcifications. Further genetic testing and auxiliary examinations revealed that the patient had hypogonadotropic hypogonadism (HH) and DAX-1 gene disorders, at which time he was diagnosed with AHC complicated by HH. He was given hormone replacement therapy, followed by regular outpatient review to adjust the medication.

CONCLUSIONS

The typical early symptoms of AHC are hyperpigmentation and ion disturbance during infantile and juvenile periods, while few patients with AHC develop puberty disorders as early symptoms. AHC is prone to being misdiagnosed as Addison's disease, and then gradually develops the symptoms of HH in adolescence. The definitive diagnosis of AHC ultimately is based on the patient's clinical presentation, laboratory results and genetic testing results.

A novel stop-loss DAX1 variant affecting its protein-interaction with SF1 precedes the adrenal hypoplasia congenital with rare spontaneous precocious puberty and elevated hypothalamic-pituitary-gonadal/adrenal axis responses

The case study unveils the likely mechanism of a novel stop-loss DAX1 variant preceding the prolonged precocious puberty in the adrenal hypoplasia congenital (AHC) boy. A boy aged five years and nine months initially examined for the primary adrenal insufficiency symptoms. Next-generation sequencing confirmed the X-linked inheritance of a novel stop-loss DAX1 variant: c.1411T>C/p.Ter471Gln associated with AHC in the patient. The patient was subjected to a brief clinical follow-up from 11 to 15.1 years of age. The effect of the mutant-DAX1 variant (p.Ter471Gln) on DAX1-steroidogenic factor 1 (SF1) (protein-protein) interaction was studied by protein-protein docking using the ClusPro-online tool. At 5.9 yrs of age, the patient exhibited precocious puberty with the secondary sexual characteristics of Tanner 2 stage (of 9-14 yrs of age). The patient showed primary adrenal insufficiency with diminished cortisol concentrations at blood serum (25 ng/ml) and urine (3.55 μg/24 h) levels. Upon steroidal exposure, the patient showed normalized serum cortisol levels of 45-61 ng/ml. However, the precocious puberty got prolonged with the increased penis length of 8.5 cm and the bone age of 18 yrs old during the follow-up. The patient showed increased basal serum adrenocorticotropic hormone (110->2000 pg/ml) and follicle-stimulating hormone (18.4-22.3 mIU/ml) concentrations. Following an elevated hypothalamic-pituitary-gonadal axis activity witnessed upon gonarellin stimulation. Protein-protein docking confirmed a weaker interaction between the mutant-DAX1 (p.Ter471Gln) protein and the wild-SF1 protein. Overall, we hypothesize the weakened mutant-DAX1-SF1 (protein-protein) interaction could govern the prolonged precocious puberty augmented with the elevated hypothalamic-pituitary-gonadal/adrenal axis responses via SF1-induced neuronal nitric oxide synthetase activation in the patient.

Primary Adrenocortical Insufficiency Case Series in the Neonatal Period: Genetic Etiologies Are More Common Than Expected

Primary adrenocortical insufficiency (PAI) is an important cause of morbidity in neonates. The most common cause of PAI in neonates is congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD). Other rarer monogenic cases, for example, adrenal hypoplasia congenita (AHC) or familial glucocorticoid deficiency, also simulate clinical manifestation of 21-OHD, leading to misdiagnosis. The therapies and prognosis of these monogenic cases of PAI are entirely different. This study aimed to compare the differences of clinical data and identify genetic etiologies of PAI cases in the neonatal period. All 7 neonates initially presented with hyperpigmentation, hyponatremia, hyperkalemia, and high serum adrenocorticotropic hormone levels. Only CAH patients showed hyperandrogenism and remarkably elevated serum 17-hydroxyprogesterone levels. All the pathogenic mutations found in CYP21A2 were well known, except c.1069C>T (exon 8). The male patient with AHC had a novel hemizygous deletion of exon 2 in DAX1. The other one with familial glucocorticoid deficiency type 1 had two novel heterozygous mutations in the gene coding melanocortin 2 receptor, c.701C>T (exon 2) and c.119delT (exon 2). Glucocorticoid and/or mineralocorticoid replacement therapy depends on the cause of PAI. Genetic testing can be performed as a alternative diagnostic approach to provide information about therapy, prognosis, and genetic counseling.