Thirty-Eight-Year Follow-Up of Two Sibling Lipoid Congenital Adrenal Hyperplasia Patients Due to Homozygous Steroidogenic Acute Regulatory (STARD1) Protein Mutation. Molecular Structure and Modeling of the STARD1 L275P Mutation

A novel variant of the STAR gene: nonclassical presentation from Turkey

OBJECTIVES

Lipoid congenital adrenal hyperplasia (LCAH) is a rare autosomal recessive disease caused by mutations in the steroidogenic acute regulatory protein (STAR) gene, expressed in the adrenal and gonadal tissues. In classical LCAH, individuals with 46, XY chromosomes present with a female appearance of the external genitalia due to insufficient androgen production. In the non-classical form, a milder phenotype is observed with male external genitalia. Here, we present a non-classical LCAH diagnosis with a newly identified c.266T>A (p.Ile89Asn) likely pathogenic homozygous variant in a 46, XY infant.

CASE PRESENTATION

A three-month-and-thirteen-day-old male proband presented with clinical features of cortisol and mineralocorticoid deficiencies. The manifestation of salt-wasting syndrome occurred relatively late, and although the external genitalia appeared male, there was a mild virilization defect. The combination of mild impairment in androgen production and severe salt-wasting syndrome is an intriguing finding in our patient. Peripheral blood samples were obtained from the patient and his family. The newly identified variant, determined by next-generation sequencing analysis, was confirmed by segregation analysis showing carrier status in both parents.

CONCLUSIONS

We aim to contribute to the literature by elucidating molecular mechanisms by presenting an atypical presentation and a newly identified variant.

Pregnancy in Congenital Adrenal Hyperplasia

Over the last several decades, children with all forms of classic congenital adrenal hyperplasia (CAH) are identified early and treated appropriately throughout childhood. As adults, women with CAH may desire to become mothers and their usual chronic therapy and disease control is often inadequate for conception. Subsequently, little data exist on their management during pregnancy. Pregnancy in women with various forms of CAH is possible with appropriate treatment. Achieving pregnancy is more complex than disease management during pregnancy.

Novel STAR Gene Variant of Congenital Lipoid Adrenal Hyperplasia With Testicular Adrenal Rests

A mutation in the steroidogenic acute regulatory protein (STAR) gene, which encodes a protein that plays a crucial role in steroid hormone synthesis, causes a severe form of congenital adrenal hyperplasia (CAH) known as lipoid CAH (LCAH). LCAH presents with primary adrenal insufficiency (PAI) as well as atypical genitalia. Individuals with LCAH require adrenal steroid hormone supplements for survival. Masculinization in males with STAR deficiency varies from incomplete to normal virilization. Radiological examinations reveal enlarged and lipid-laden adrenals. A 10-year-old boy born of second-degree consanguinity presented with weight gain and hyperpigmentation for 1 year. He was diagnosed with PAI at age 7 months and treated with hydrocortisone and fludrocortisone. Dynamic adrenal gland testing revealed undetectable hormone reserves. Imaging detected hypoplastic adrenals and a small testis with testicular adrenal rests (TART). Genetic analysis indicated a novel homozygous pathogenic variant of STAR in exon 7, c.814C > G(pArg272Gly) associated with LCAH (OMIM No. 201710). Testing revealed that asymptomatic family members and relatives were heterozygotes for the variant. The patient was diagnosed with nonclassic LCAH with hypoplastic adrenals and TART. Adequate hormone supplementation resulted in TART regression. This genetic variation is reported for the first time.

Lipoid Congenital Adrenal Hyperplasia With a Novel StAR Gene Mutation

Lipoid congenital adrenal hyperplasia (LCAH) is characterized by disturbance of adrenal and gonadal steroidogenesis (OMIM:201710). It is caused by mutation in the Steroidogenic Acute Regulatory Protein (StAR). We report a classic case of LCAH in a neonate (46, XY) with phenotypic female genitalia who presented with significant salt loss with a novel homozygous variant mutation c.745-1G>C p. in StAR gene.

Mitochondrial Cholesterol Metabolites in a Bile Acid Synthetic Pathway Drive Nonalcoholic Fatty Liver Disease: A Revised "Two-Hit" Hypothesis

The rising prevalence of nonalcoholic fatty liver disease (NAFLD)-related cirrhosis highlights the need for a better understanding of the molecular mechanisms responsible for driving the transition of hepatic steatosis (fatty liver; NAFL) to steatohepatitis (NASH) and fibrosis/cirrhosis. Obesity-related insulin resistance (IR) is a well-known hallmark of early NAFLD progression, yet the mechanism linking aberrant insulin signaling to hepatocyte inflammation has remained unclear. Recently, as a function of more distinctly defining the regulation of mechanistic pathways, hepatocyte toxicity as mediated by hepatic free cholesterol and its metabolites has emerged as fundamental to the subsequent necroinflammation/fibrosis characteristics of NASH. More specifically, aberrant hepatocyte insulin signaling, as found with IR, leads to dysregulation in bile acid biosynthetic pathways with the subsequent intracellular accumulation of mitochondrial CYP27A1-derived cholesterol metabolites, (25R)26-hydroxycholesterol and 3β-Hydroxy-5-cholesten-(25R)26-oic acid, which appear to be responsible for driving hepatocyte toxicity. These findings bring forth a "two-hit" interpretation as to how NAFL progresses to NAFLD: abnormal hepatocyte insulin signaling, as occurs with IR, develops as a "first hit" that sequentially drives the accumulation of toxic CYP27A1-driven cholesterol metabolites as the "second hit". In the following review, we examine the mechanistic pathway by which mitochondria-derived cholesterol metabolites drive the development of NASH. Insights into mechanistic approaches for effective NASH intervention are provided.

Characterization of Two Novel Variants of the Steroidogenic Acute Regulatory Protein Identified in a Girl with Classic Lipoid Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) consists of several autosomal recessive disorders that inhibit steroid biosynthesis. We describe a case report diagnosed with adrenal insufficiency due to low adrenal steroids and adrenocorticotropic hormone excess due to lack of cortisol negative feedback signaling to the pituary gland. Genetic work up revealed two missense variants, p.Thr204Arg and p.Leu260Arg in the STAR gene, inherited by both parents (non-consanguineous). The StAR protein supports CYP11A1 enzyme to cleave the side chain of cholesterol and synthesize pregnenolone which is metabolized to all steroid hormones. We used bioinformatics to predict the impact of the variants on StAR activity and then we performed functional tests to characterize the two novel variants. In a cell system we tested the ability of variants to support cholesterol conversion to pregnenolone and measured their mRNA and protein expression. For both variants, we observed loss of StAR function, reduced protein expression and categorized them as pathogenic variants according to guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. These results fit the phenotype of the girl during diagnosis. This study characterizes two novel variants and expands the list of missense variants that cause CAH.

Lipoid congenital adrenal hyperplasia due to steroid acute regulatory protein (STAR) variants in Three Chinese patients

Congenital adrenal hyperplasia (CAH) encompasses a group of autosomal recessive diseases characterized by enzymatic defects in steroid synthesis. Lipoid congenital adrenal hyperplasia (LCAH) is the most severe form of CAH, insofar as the initial step of steroid synthesis is impaired. Variants in the steroid acute regulatory (STAR) gene are responsible for LCAH. To describe the clinical and genetic characteristics of three Chinese patients with LCAH. We analyzed the history, clinical manifestations, physical examination, laboratory data, and computed tomography findings of three girls with LCAH. The STAR gene of the probands and their parents were sequenced using genomic DNA. The wild-type and mutant STAR cDNAs were inserted into the pcDNA3.1(+) plasmid vector and transiently transfected into COS7 cells. The enzymatic activities of the wild-type and mutant STAR were evaluated by the enzyme-dependent conversion efficiency of cholesterol to pregnenolone. We identified the molecular genetic abnormalities in three patients with LCAH. All three patients had a female phenotype: karyotype of patients 1 and 2 was 46, XY and patient 3 was 46, XX. DNA sequencing revealed compound heterozygous variants in STAR for three probands. Two variants, c.659A > G/p.His220Arg and exon 2-3 deletion, were novel. In vitro functional studies uncovered that the His220Arg variant retained 19.2 % of enzymatic activity compared to that of the wild type.

Steroidogenic Acute Regulatory Protein: Structure, Functioning, and Regulation

Steroidogenesis takes place mainly in adrenal and gonadal cells that produce a variety of structurally similar hormones regulating numerous body functions. The rate-limiting stage of steroidogenesis is cholesterol delivery to the inner mitochondrial membrane, where it is converted by cytochrome P450scc into pregnenolone, a common precursor of all steroid hormones. The major role of supplying mitochondria with cholesterol belongs to steroidogenic acute regulatory protein (STARD1). STARD1, which is synthesized de novo as a precursor containing mitochondrial localization sequence and sterol-binding domain, significantly accelerates cholesterol transport and production of pregnenolone. Despite a tremendous interest in STARD1 fueled by its involvement in hereditary diseases and extensive efforts of numerous laboratories worldwide, many aspects of STARD1 structure, functioning, and regulation remain obscure and debatable. This review presents current concepts on the structure of STARD1 and other lipid transfer proteins, the role of STARD1 in steroidogenesis, and the mechanism of its functioning, as well as identifies the most controversial and least studied questions related to the activity of this protein.

Pubertal Development and Pregnancy Outcomes in 46,XX Patients With Nonclassic Lipoid Congenital Adrenal Hyperplasia

CONTEXT

Lipoid congenital adrenal hyperplasia (LCAH) is characterized by a disorder of steroidogenesis in both adrenal glands and gonads. 46,XX patients with classic LCAH usually have thelarche and menarche but show anovulatory menstruations and subsequent premature menopause. Only three patients with classic LCAH have been reported to successfully achieve delivery with the aid of assisted reproductive therapies for conception and progesterone replacement therapy during early pregnancy. In contrast, pubertal development and pregnancy outcomes in patients with nonclassic LCAH have not been fully elucidated.

CASE DESCRIPTION

We report four Japanese women who had a diagnosis of primary adrenal insufficiency during infancy or childhood and carried compound heterozygous STAR mutations (p.Gln258* and p.Arg188His, p.Gln258* and p.Met225Thr, and p.Gln258* and p.Arg272Cys). In all four patients, thelarche and menarche spontaneously occurred from 10 to 11 years of age and from 12 to 14 years of age, respectively. Subsequently, their menstruation cycles were regular at almost 1-month intervals. Patient 1 conceived naturally twice, and patient 2 conceived with the use of clomiphene citrate for ovulation induction. These two patients maintained the pregnancies without progesterone replacement therapy and successfully delivered children.

CONCLUSION

Patients with nonclassic LCAH maintain ovarian function, which enables normal pubertal development and a successful pregnancy outcome without progesterone replacement therapy.

Long-term follow-up in a Chinese child with congenital lipoid adrenal hyperplasia due to a StAR gene mutation

BACKGROUND

Congenital lipoid adrenal hyperplasia (CLAH) is an extremely rare and the most severe form of congenital adrenal hyperplasia. Typical features include disorder of sex development, early-onset adrenal crisis and enlarged adrenal glands with fatty accumulation.

CASE PRESENTATION

We report a case of CLAH caused by mutations in the steroidogenic acute regulatory protein (StAR) gene. The patient had typical early-onset adrenal crisis at 2 months of age. She had normal-appearing female genitalia and a karyotype of 46, XY. The serum cortisol and adrenal steroids levels were always nearly undetectable, but the adrenocorticotropic hormone levels were extremely high. Genetic analysis revealed compound heterozygous mutations at c. 229C > T (p.Q77X) in exon 3 and c. 722C > T (p.Q258X) in exon 7 of the StAR gene. The former mutation was previously detected in only two other Chinese CLAH patients. Both mutations cause truncation of the StAR protein. The case reported here appears to be a classic example of CLAH with very small adrenal glands and is the second reported CLAH case with small adrenal glands thus far. In a 15-year follow-up, the patient's height was approximately average for females before age 4 and fell to - 1 SDS at 10 years of age. Her bone age was similar to her chronological age from age 4 to age 15 years.

CONCLUSIONS

In conclusion, this is a classic case of CLAH with exceptionally small adrenal glands. Q77X mutation seems to be more common in Chinese CLAH patients. Additionally, this is the first report of the growth pattern associated with CLAH after a 15-year follow-up.

A Case of Two Sisters Suffering from 46,XY Gonadal Dysgenesis and Carrying a Mutation of a Novel Candidate Sex-Determining Gene STARD8 on the X Chromosome

Identification of novel genes involved in sexual development is crucial for understanding disorders of sex development (DSD). Here, we propose a member of the START domain family, the X chromosome STARD8, as a DSD candidate gene. We have identified a missense mutation of this gene in 2 sisters with 46,XY gonadal dysgenesis, inherited from their heterozygous mother. Gonadal tissue of one of the sisters contained Leydig cells overloaded with cholesterol droplets, i.e., structures previously identified in 46,XY DSD patients carrying mutations in the STAR gene encoding another START domain family member, which is crucial for steroidogenesis. Based on the phenotypes of our patients, we propose a dual role of STARD8 in sexual development, namely in testes determination and testosterone synthesis. However, further studies are needed to confirm the involvement of STARD8 in sexual development.

In vitro fertilization-frozen embryo transfer in a patient with cytochrome P450 oxidoreductase deficiency: a case report

Cytochrome P450 enzymes are required for the synthesis of cholesterol and steroid hormones. Cytochrome P450 oxidoreductase (POR) donates electrons to microsomal cytochrome P450 enzymes. POR deficiency (PORD) is a rare autosomal recessive disease. In patients with PORD, steroid hormone synthesis is disrupted, which can cause infertility. The objective of this study was to report on a case of in vitro fertilization-frozen embryo transfer (IVF-FET) in a patient with PORD. The patient's hormone (i.e. 17α-hydroxyprogesterone) and electrolyte levels were within normal ranges ordinarily. Upon controlled ovarian stimulation, follicle growth was normal, but serum estrogen and progesterone levels were low and high, respectively. The serum progesterone level was elevated after long-acting gonadotropin-releasing hormone agonist treatment, and an endometrial biopsy showed a change in the proliferative phase. Genetic tests detected homozygous mutations (c.976 T > G, p.Y326D) in exon 10 of the POR gene. The frozen embryo was transferred during the administration of hormone replacement therapy. No significant morphological or metabolic abnormalities were observed in the neonate. Our findings suggest that infertile women with normal hormone levels may have metabolic diseases such as PORD. Further studies are needed to determine the cause of these diseases and to assist pregnancy in such women.

Congenital adrenal hyperplasia

Congenital adrenal hyperplasia is a group of autosomal recessive disorders encompassing enzyme deficiencies in the adrenal steroidogenesis pathway that lead to impaired cortisol biosynthesis. Depending on the type and severity of steroid block, patients can have various alterations in glucocorticoid, mineralocorticoid, and sex steroid production that require hormone replacement therapy. Presentations vary from neonatal salt wasting and atypical genitalia, to adult presentation of hirsutism and irregular menses. Screening of neonates with elevated 17-hydroxyprogesterone concentrations for classic (severe) 21-hydroxylase deficiency, the most common type of congenital adrenal hyperplasia, is in place in many countries, however cosyntropin stimulation testing might be needed to confirm the diagnosis or establish non-classic (milder) subtypes. Challenges in the treatment of congenital adrenal hyperplasia include avoidance of glucocorticoid overtreatment and control of sex hormone imbalances. Long-term complications include abnormal growth and development, adverse effects on bone and the cardiovascular system, and infertility. Novel treatments aim to reduce glucocorticoid exposure, improve excess hormone control, and mimic physiological hormone patterns.

Congenital Adrenal Hyperplasia

The congenital adrenal hyperplasias comprise a family of autosomal recessive disorders that disrupt adrenal steroidogenesis. The most common form is due to 21-hydroxylase deficiency associated with mutations in the 21-hydroxylase gene, which is located at chromosome 6p21. The clinical features associated with each disorder of adrenal steroidogenesis represent a clinical spectrum that reflect the consequences of the specific mutations. Treatment goals include normal linear growth velocity and "on-time" puberty in affected children. For adolescent and adult women, treatment goals include regularization of menses, prevention of progression of hirsutism, and preservation of fertility. For adolescent and adult men, prevention and early treatment of testicular adrenal rest tumors is beneficial. In this article key aspects regarding pathophysiology, diagnosis, and treatment of congenital adrenal hyperplasia are reviewed.