An update of genetic basis of PCOS pathogenesis

ABSTRACT Polycystic ovary syndrome (PCOS) is a common and complex endocrine disorder that affects 5-20% of reproductive age women. PCOS clinical symptoms include hirsutism, menstrual dysfunction, infertility, obesity and metabolic syndrome. There is a wide heterogeneity in clinical manifestations and metabolic complications. The pathogenesis of PCOS is not fully elucidated, but four aspects seem to contribute to the syndrome to different degrees: increased ovarian and/or adrenal androgen secretion, partial folliculogenesis arrest, insulin resistance and neuroendocrine axis dysfunction. A definitive etiology remains to be elucidated, but PCOS has a strong heritable component indicated by familial clustering and twin studies. Genome Wide Association Studies (GWAS) have identified several new risk loci and candidate genes for PCOS. Despite these findings, the association studies have explained less than 10% of heritability. Therefore, we could speculate that different phenotypes and subphenotypes are caused by rare private genetic variants. Modern genetic studies, such as whole exome and genome sequencing, will help to clarify the contribution of these rare genetic variants on different PCOS phenotypes. Arch Endocrinol Metab. 2018;62(3):352-61

An activating mutation in the CRHR1 gene is rarely associated with pituitary-dependent hyperadrenocorticism in poodles

OBJECTIVES: Pituitary-dependent hyperadrenocorticism is the most common cause of naturally occurring hypercortisolism in dogs. CRHR1 expression in human and dog corticotrophinomas suggested that this gene affects pituitary tumorigenesis. The present study aimed to investigate mutations in the CRHR1 coding region in poodles with pituitary-dependent hyperadrenocorticism. METHODS: Fifty poodles with pituitary-dependent hyperadrenocorticism and 50 healthy poodles were studied. Genomic DNA was amplified by PCR and analyzed by Sanger sequencing. RESULTS: The novel CRHR1 p.V97M mutation was identified in one dog. This valine residue, located in the amino-terminal extracellular domain, exhibits high affinity for its corticotropin-releasing hormone (CRH) ligand. Bioinformatic analysis revealed structural rearrangements in the mutant protein, with a 17% increase in the surface binding affinity between CRHR1 and CRH. In vitro functional studies showed that mutant CRHR1 induced higher ACTH secretion than the wild type after stimulation with human CRH. CONCLUSION: These results suggest that germline activating mutations in CRHR1 may be a rare cause of pituitary hyperadrenocorticism in poodles.

Long-term follow-up of a female with congenital adrenal hyperplasia due to P450-oxidoreductase deficiency

SUMMARY P450 oxidoreductase deficiency (PORD) is a variant of congenital adrenal hyperplasia that is caused by POR gene mutations. The POR gene encodes a flavor protein that transfers electrons from nicotinamide adenine dinucleotide phosphate (NADPH) to all microsomal cytochrome P450 type II (including 21-hydroxylase, 17α-hydroxylase 17,20 lyase and aromatase), which is fundamental for their enzymatic activity. POR mutations cause variable impairments in steroidogenic enzyme activities that result in wide phenotypic variability ranging from 46,XX or 46,XY disorders of sexual differentiation, glucocorticoid deficiency, with or without skeletal malformations similar to Antley-Bixler syndrome to asymptomatic newborns diagnosed during neonatal screening test. Little is known about the PORD long-term evolution. We described a 46,XX patient with mild atypical genitalia associated with severe bone malformation, who was diagnosed after 13 years due to sexual infantilism. She developed large ovarian cysts and late onset adrenal insufficiency during follow-up, both of each regressed after hormone replacement therapies. We also described a late surgical approach for the correction of facial hypoplasia in a POR patient.

Association of glucocorticoid receptor polymorphisms with clinical and metabolic profiles in polycystic ovary syndrome

OBJECTIVES: We aimed to investigate whether glucocorticoid receptor gene polymorphisms are associated with clinical and metabolic profiles in patients with polycystic ovary syndrome. Polycystic ovary syndrome is a complex endocrine disease that affects 5-8% of women and may be associated with metabolic syndrome, which is a risk factor for cardiovascular disease. Cortisol action and dysregulation account for metabolic syndrome development in the general population. As glucocorticoid receptor gene (NR3C1) polymorphisms regulate cortisol sensitivity, we hypothesized that variants of this gene may be involved in the adverse metabolic profiles of patients with polycystic ovary syndrome. METHOD: Clinical, metabolic and hormonal profiles were evaluated in 97 patients with polycystic ovary syndrome who were diagnosed according to the Rotterdam criteria. The alleles of the glucocorticoid gene were genotyped. Association analyses were performed using the appropriate statistical tests. RESULTS: Obesity and metabolic syndrome were observed in 42.3% and 26.8% of patients, respectively. Body mass index was positively correlated with blood pressure, triglyceride, LDL-c, total cholesterol, glucose and insulin levels as well as HOMA-IR values and inversely correlated with HDL-c and SHBG levels. The BclI and A3669G variants were found in 24.7% and 13.4% of alleles, respectively. BclI carriers presented a lower frequency of insulin resistance compared with wild-type subjects. CONCLUSION: The BclI variant is associated with a lower frequency of insulin resistance in women with polycystic ovary syndrome. Glucocorticoid gene polymorphism screening during treatment of the syndrome may be useful for identifying subgroups of at-risk patients who would benefit the most from personalized treatment. .

Mineralocorticoid replacement during infancy for salt wasting congenital adrenal hyperplasia due to 21-hydroxylase deficiency

OBJECTIVE: The protocols for glucocorticoid replacement in children with salt wasting 21-hydroxylase deficiency are well established; however, the current recommendation for mineralocorticoid replacement is general and suggests individualized dose adjustments. This study aims to retrospectively review the 9-∝-fludrocortisone dose regimen in salt wasting 21-hydroxylase deficient children who have been adequately treated during infancy. METHODS: Twenty-three salt wasting 21-hydroxylase deficient patients with good anthropometric and hormonal control were followed in our center since diagnosis. The assessments of cortisone acetate and 9-∝-fludrocortisone doses, anthropometric parameters, and biochemical and hormonal levels were rigorously evaluated in pre-determined intervals from diagnosis to two years of age. RESULTS: The 9-∝-fludrocortisone doses decreased over time during the first and second years of life; the median fludrocortisone doses were 200 µg at 0-6 months, 150 µg at 7-18 months and 125 µg at 19-24 months. The cortisone acetate dose per square meter was stable during follow-up (median = 16.8 mg/m²/day). The serum sodium, potassium and plasma rennin activity levels during treatment were normal, except in the first month of life, when periodic 9-∝-fludrocortisone dose adjustments were made. CONCLUSIONS: The mineralocorticoid needs of salt wasting 21-hydroxylase deficient patients are greater during early infancy and progressively decrease during the first two years of life, which confirms that a partial aldosterone resistance exists during this time. Our study proposes a safety regiment for mineralocorticoid replacement during this critical developmental period.

Pharmacogenetics of glucocorticoid replacement could optimize the treatment of congenital adrenal hyperplasia due to 21-hydroxylase deficiency

INTRODUCTION: 21-hydroxylase deficiency is an autosomal recessive disorder that causes glucocorticoid deficiency and increased androgen production. Treatment is based on glucocorticoid replacement; however, interindividual variability in the glucocorticoid dose required to achieve adequate hormonal control has been observed. OBJECTIVE: The present study aimed to evaluate the association between polymorphic variants involved inglucocorticoid action and/or metabolism and the mean daily glucocorticoid dose in 21-hydroxylase deficiency patients. METHODS: We evaluated 53 patients with classical forms of 21-hydroxylase deficiency who were receiving cortisone acetate. All patients were between four and six years of age and had normal androgen levels. RESULTS: The P450 oxidoreductase A503V, HSD11B1 rs12086634, and CYP3A7*1C variants were found in 19 percent, 11.3 percent and 3.8 percent of the patients, respectively. The mean ± SD glucocorticoid dose in patients with the CYP3A7*1C and wild-type alleles was 13.9 ± 0.8 and 19.5 ± 3.2 mg/m²/d, respectively. We did not identify an association between the P450 oxidoreductase or HSD11B1 allelic variants and the mean glucocorticoid dose. CONCLUSION: Patients carrying the CYP3A7*1C variant required a significantly lower mean glucocorticoid dose. Indeed, the CYP3A7*1C allele accounted for 20 percent of the variability in the cortisone acetate dose. The analysis of genes involved in glucocorticoid metabolism may be useful in the optimization of treatment of 21-hydroxylase deficiency.