[Gonadotropin-dependent precocious puberty: genetic and clinical characteristics].

BACKGROUND: In 90% cases of girls and 25-60% cases of boys the cause of gonadotropin-dependent precocious puberty (PP) is unclear. Up to 25-27.5% of gonadotropin-dependent PP cases are monogenic and suggest autosomal-dominant inheritance with incomplete sex-dependent penetrance. To date, mutations in genes KISS1, KISS1R, MKRN3, DLK1 have been described as causal variants leading to precocious hypothalamic-pituitary axis activation in childhood. Genetic testing in patients with hereditary forms of PP can expand our knowledge of underlying molecular mechanisms of the disease and it  is also necessary for genetic counselling. AIM: To study clinical features and genetic characteristics of patients with idiopathic gonadotropin-dependent precocious puberty. MATERIALS AND METHODS: A group of patients with idiopathic gonadotropin-dependent precocious puberty and positive family history (early or precocious puberty) was examined. Laboratory and instrumental diagnostic tests, full-exome sequencing (NGS, next-generation sequencing) were provided for all patients. RESULTS: The study included 30 patients (29 girls, 1 boy) with idiopathic gonadotropin-dependent precocious puberty. The median of patients age at the time of the examination was 7,2 years [6,5; 7,7]. Positive family history presented in all cases: in 40% of patients on father's side, in 37% - on mother's side, in 23% of patients PP was diagnosed in siblings. The fullexome sequencing was conducted to 21 patients: in 61,9% of cases (95% CI [40;79]) nucleotide variants were identified   in genes, associated with gonadotropin-dependent precocious puberty. MKRN3 gene defect was detected in most cases (77% cases (95% CI [49; 92]), which consistent with international data on its highest prevalence in the monogenic forms of PP. In 23% of cases (95% CI [7; 50]) nucleotide variants were identified in other candidate genes associated with neuroontogenesis and neuroendocrine regulation mechanisms of hypothalamic-pituitary axis. CONCLUSION: Our study confirms that detailed family history data in children with PP provides a rational approach to molecular-genetic testing. Data of inheritance pattern and clinical manifestations will simplify the diagnosis of hereditary forms of disease and enhance genetic counselling of families, followed by timely examination and administration of pathogenetic therapy.

[DICER1 syndrome: clinical variety endocrine manifestations and features of diagnostics].

DICER1 syndrome is a rare genetic disorder with the progressive development of malignant and non-malignant diseases in childhood. The cause of this syndrome is a dusfunction of the endoribonuclease DICER, which plays an important role in the processing of microRNAs with subsequent regulation of the control of the expression of oncogenes and tumor suppressor genes. Clinical manifestations of dyseropathies is very different and may include both endocrine manifestations - multinodular goiter, differentiated thyroid cancers, ovarian stromal tumors, pituitary blastoma, and non-endocrine formations - pleuropulmonary blastoma, cystic nephroma, pineoblastoma. The presence of somatic mutations of the DICER1 gene is a resultant stage in the pathogenesis of dyseropathies, determining the further path of oncogenesis. At present, DICER1 syndrome is diagnosed extremely rarely, which leads to late detection of the components of the disease in the patient, late diagnosis of neoplasms, lack of family counseling. Diagnosis at the early stages of the disease, the development of screening programs for the management of these patients allows minimizing the risks of developing more malignant, aggressive forms of the disease.

[Primary hyperparathyroidism in children].

BACKGROUND:  Primary hyperparathyroidism (PHPT) is an endocrine disorder characterized by excessive secretion of parathyroid hormone (PTH) with upper-normal or elevated blood calcium levels due to primary thyroid gland pathology. PHPT is a rare pathology in children, with a prevalence of 2-5:100,000 children according to the literature. Due to the non-specificity of clinical manifestations at onset (nausea, vomiting, abdominal pain, emotional lability), the disease may remain undiagnosed for a long time. AIM:  To study the features of the course and molecular genetic basis of primary hyperparathyroidism in children. MATERIALS AND METHODS:  Retrospective observational study of 49 patients diagnosed with primary hyperparathyroidism. All patients underwent a comprehensive laboratory-instrumental and molecular genetic study at the Institute of Pediatric Endocrinology, Endocrinology Research Center of Russia in the period 2014-2022. RESULTS:  The first clinical symptoms of PHPT were noted at the age of 13.8 years [10.6; 1 5.2], among which fatigue, headaches, dyspepsia, lower limb pain, and fractures were the most common. The age of diagnosis was 15.81 years [13.1; 16.8], all children were found to have high levels of PTH, total and ionized calcium, with hypophosphatemia in 93.9% of patients (n=46) and hypercalciuria in 43% (n=21). Five out of 49 patients (10.2%) were found to have ectopy of the thyroid: 3 showed an intrathyroidal location, 2 in the mediastinal region. Molecular genetic study revealed mutations in 32.7% of patients (n=16, CI (21; 47)), mutations in MEN1 being the most frequent (n=11). Pathogenic variants in CDC73 were detected in 3 patients, RET - in 2. Among the operated 39 patients, adenoma of the thyroid was detected in 84.6% of cases (n=33), hyperplasia in 7.7% (n=3), atypical adenoma in 5.1% (n=2), carcinoma in 5.1% of cases (n=2). CONCLUSION:  The paper presents the peculiarities of the course and the results of molecular genetic study of pediatric PHPT. This sample is the largest among those published in the Russian Federation.

[The clinical case of IgG4-related thyroid disease in a 6-year-old child].

IgG4-related disease is a rare chronic pathology manifested by lymphoplasmacytic infiltration of one or more organs, the formation of storiform fibrosis, tissue edema, and an increase of IgG4 in the blood. This disease was singled out as an independent nosological unit only in 2001. The incidence is less than 1 in 100,000 people per year. Almost any organ can be affected in IgG4-related disease. The association of Riedel's thyroiditis with IgG4 was established in 2010. Riedel's thyroiditis is an extremely rare inflammatory disease of the thyroid gland, which diagnosis is complicated by an atypical course and the absence of characteristic symptoms. Less than 300 clinical cases of the disease have been described in the world, only two from them were in children. This article presents a clinical case of a 6-year-old boy with Riedel's thyroiditis.

[Donohue syndrome and use of continuous subcutaneous IGF1 pump therapy].

Donohue syndrome (DS), also called Leprechaunism, is the most severe form of insulin resistance associated with biallelic mutations in INSR gene (OMIM: 147670). The approximate incidence of this syndrome is 1 per 1000000 births. Patients are present with typical clinical features such as intrauterine growth retardation, facial dysmorphism, severe metabolic disturbances, hepatomegaly and hypertrophic cardiomyopathy. Most DS patients die within the first two years of life due to respiratory infections, severe hypoglycemia or progressive cardiomyopathy. Treatment options are limited and no specific therapy exist for DS. Given the similarities between insulin and insulin-like growth factor 1 (IGF-1) receptors, recombinant human IGF-1 (rhIGF-1) has been used to treat severe insulin resistance including DS.We report the case of a male patient with genetically confirmed Donohue syndrome, successfully treated with continuous subcutaneous IGF1 infusion via insulin pump. We observed improvement of glycemic control, liver function and cardiac hypertrophy regression following 15-month IGF1 therapy.

[Clinical guidelines «Precocious puberty¼].

The precocious puberty is an urgent problem of pediatric endocrinology characterized by clinical and pathogenetic heterogeneity. The appearance of secondary sex characteristics before the age of 8 years in girls and 9 years in boys requires timely diagnosis and the appointment of pathogenetically justified treatment in order to achieve the target indicators of final growth and prevent social deprivation. The developed clinical guidelines are the main working tool of the practitioner. They briefly and structurally present the main information about the epidemiology and modern classification of рrecocious puberty, methods of its diagnosis and treatment based on the principles of evidence-based medicine.

[Clinical and molecular genetic features of 3 family cases of the central precocious puberty, due to MKRN3 gene defects].

Gonadotropin-dependent precocious puberty (central) is a condition resulting from the early (up to 8 years in girls and 9 years in boys) reactivation of the hypothalamic-pituitary-gonadal axis. An increase in the secretion of sex steroids by the gonads in this form is a consequence of the stimulation of the sex glands by gonadotropic hormones of the pituitary gland. In the absence of central nervous system abnormalities, CPP is classified as idiopathic and as familial in some cases, emphasizing the genetic origin of this disorder. Loss-of-function mutations in Makorin Ring Finger Protein 3 (MKRN3) are the most common identified genetic cause of central precocious puberty compared to sporadic cases. In the present study we performed the first descrition of 3 family cases of central precocious puberty duo to novel MKRN3 gene mutation detected by NGS in the Russian Federation.

[Clinical and molecular genetic features of cases of isolated hypogonadotropic hypogonadism, associated with defects in GNRHR genes].

Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder characterised by lack of pubertal development and infertility, due to deficient production, secretion or action of gonadotropin-releasing hormone (GnRH). Clinically, there are variants of CHH with hypo-/anosmia (Kalman syndrome) and normosmic hypogonadotropic hypogonadism. Given a  growing list of gene mutations accounting for CHH, the application of next generation sequencing (NGS) comprises an excellent molecular diagnostic approach because it enables the simultaneous evaluation of many genes. Biallelic mutations in GNRHR gene lead to the development of hypogonadotropic hypogonadism with normosmia. In this paper, we describe 16 patients with proven GnRH resistance and estimate the frequency of pathogenic variants in the GNRHR gene in the Russian population.

[Clinical Findings in Two patients with DSD 46XY caused by new variant of the Desert Hedgehog Gene and review of the literature of the role of DHH signaling pathway in sex development].

Mutations in the gene DHH are an extremely rare cause of disorders of sex development 46,XY (DSD,46XY). The article describes the clinical cases of two unrelated patients with gonadal dysgenesis 46,XY with female phenotype. By using a next generation sequencing method, in both cases the same biallelic variant substitution c. 419T>G in the DHH gene was revealed. Taking into account the data on the role of DHH in the formation of the nervous system, the diagnosis of minifascicular polyneuropathy at the preclinical stage was confirmed in both cases. These cases demonstrate the value of using NGS, which allows simultaneous analysis of a wide range of candidate genes in DSD and the diagnosis of comorbidities before the development of the clinical picture. These are the first descriptions of patients with mutations in the DHH gene in the Russian population.

[Erratum: clinical and molecular characteristics of patients with 46,xy dsd due to nr5a1 gene mutations (Probl Endokrinol (Mosk). 2020 Sep 16;66(3):62-69. Russian. doi: 10.14341/probl12445)].

n the article some corrections were needed. Abstract: "Heterozygous SF1 variants were found in 36 out of 310 (11.6%) of cases, among them 15 were not previously described". has been corrected to read "Heterozygous SF1 variants were found in 36 out of 310 (11.6%) of cases, among them 22 were not previously described". Results: "Heterozygous SF1 variants were found in 36 out of 310 (11.6%) of cases, among them 15 were not previously described", has been corrected to read "Heterozygous SF1 variants were found in 36 out of 310 (11.6%) of cases, among them 22 were not previously described". Among the newly identified variants in the NR1A1 gene, two lead to the premature stop codon -p. Y197X and p. Y25X, two lead to a shift in the reading frame-p. N385fs and p. L245fs, which does not allow us to doubt their pathogenicityAmong the previously undescribed variant changes, 5 missense mutations (p. C283Y, p. C283B, p.H24Q, p.M126K, p.E81K) and 1  synonymous substitution affecting the splicing site (E330E) were evaluated as pathogenic, and 5 others as probably pathogenic.Has been corrected to read: Among the newly identified variants in the NR1A1 gene, two lead to the premature stop codon -p. Y197X and p. Y25X, two lead to a shift in the reading frame - p.N385SfsX10 and p.L245AfsX53, which does not allow us to doubt their pathogenicity Among the previously undescribed variants, 5 missense mutations (p.C283Y, p.С283F, p.H24Q, p.M126K, p.A82T) and 1 synonymous substitution affecting the splicing site (E330E) were predicted as pathogenic, and 5 others as probably pathogenic by calculating pathogenicity. The authors apologize for these errors.

[Somatic mutations in the androgen receptor gene as the cause of androgen insensitivity syndrome].

Androgen insensitivity syndrome is an X-linked disorder characterized by either complete or partial insensitivity of target tissues to androgens. This disease is caused by mutations in the AR gene located on the Х chromosome. Currently, there are no distinct clinical, biochemical, or hormonal markers that would allow one to differentiate androgen insensitivity syndrome from a number of other forms of 46,XY disorders of sex development. Therefore, final verification of this condition is based on the results of molecular genetic tests. Although more than 1,000 point mutations in the AR gene have been reported, somatic mutations in this gene have been described rather rarely. However, this very type of mutations makes the course of this disease difficult to predict, since various cells in the human body contain both normal and mutant receptors. Somatic mosaicism can cause spontaneous masculization during puberty in individuals born with a completely normal female phenotype. In this case report, we describe the phenotypic and molecular genetic characteristics of eight patients with various forms of androgen insensitivity syndrome caused by somatic mutations in the AR gene.