[Kalmann syndrome in monozygous twins as an isolated manifestation of the SOX10 gene defect].

More than 30 genes are known to take part in hypothalamic-pituitary-gonadal axis development at the date and role of more than 10 other genes is studied. Despite it about 50% of isolated hypogonadotropic hypogonadism cases still have no molecular genetic explanation.A number of specific associations between iHH and different not-reproductive manifestations called syndromic forms are distinguished in general group of iHH. For example, the combination of Kalmann syndrome with sensorineural hearing loss is known as manifestation for defects of some genes encoding factors of neuronal migration; in patients with this phenotype CHD7, SOX10 genes defects are most frequent. However, defects in the genes of neuronal migration factors are characterized by a wide variability of phenotype, which is explained by the epigenetic mechanisms influence. Carriers of the mutation within the same family may lack some non-reproductive manifestations as well as hypogonadism.Here we present a case of Kalmann syndrome in monozygous twins, caused by a previously not described heterozygous mutation c.462C> G: p.I154M in the SOX10 gene in the absence of sensorineural hearing loss. The mutation was inherited from a father who has only isolated anosmia in the phenotype. This mutation was identified during full exome sequencing. This unique observation for Russia shows on the one hand expediency to check SOX10 sequence in addition to the other factors of neuronal migration and differentiation and, on the other hand, the prospect of full exome sequencing in a group of patients with undifferentiated iHH.

[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.

[Familial case of hypogonadotropic hypogonadism as the CHARGE syndrome manifestation].

CHARGE syndrome is a rare autosomal dominant disease caused by CHD7 gene mutations. Individuals with CHARGE display a wide spectrum of clinical features. It might be presented only as a delay puberty, which does not require any hormone replacement therapy to severe CHARGE phenotype, requiring a multidisciplinary therapeutic approach. Wild spectrum of clinical presentation can be seen even among the patients with identical mutation. Diagnosis might be suspected by a combination of major and minor clinical criteria of this disorder, but molecular genetic analysis is mandatory for final verification. Accurate diagnosis is essential to informing patients about all possible clinical features, reproductive status and choosing the correct treatment approach. The most common endocrine abnormality in patients with CHARGE syndrome is the disturbance in gonadotropins function ranged from delay puberty to persistent hypogonadotropic hypogonadism with different olfactory phenotypes, resulted by specific role of CHD7 in GnRH neuronal embryogenesis.We describe a familial case of CHARGE syndrome with significant intrafamilial clinical heterogeneity due to CHD7 gene mutation.

[Morphological characteristics of pituitary adenomas in the phenocopy of multiple endocrine neoplasia type 1].

BACKGROUND: Multiple endocrine neoplasia type 1 (MEN 1) is a rare autosomal dominant disorder caused by mutations in the MEN1 gene, which encodes the menin protein. If a patient has the MEN 1 phenotype in the absence of mutations in the MEN1 gene, the condition is classified as a phenocopy of this syndrome. Although significant progress has been made in understanding the function of menin, its role in the oncogenesis of the endocrine glands is still being elucidated. Due to its key role in physiological and pathological processes, the assessment of the menin expression can provide valuable information. AIM: to determine whether there are any differences in the expression of menin in the pituitary adenomas (PA) in patients with phenocopy of MEN 1 (phMEN 1) and genetically confirmed MEN 1 (gMEN 1) compared with their sporadic forms. MATERIALS AND METHODS: immunohistochemical assessment of the menin expression was carried out in PA of patients with gMEN 1, phMEN 1 and sporadic acromegaly (SA), surgically treated in 2008-2020. IHC was performed using antibodies to menin, PRL, GH, ACTH, FSH, TSH, Pit-1, T-box, ERA on previously prepared histological section. RESULTS: The study included 35 samples of PA: gMEN 1 - 9 samples, phMEN 1 - 12 (somatotropinomas + PHPT); CA - 14  samples. The patients were comparable by gender, adenoma size, and drug intake. The gMEN  1 group differed from phMEN 1 and SA by age (p = 0.0005). In patients with gMEN 1, the expression of menin varied from no staining (5/9) to intense cytoplasm staining. Cytoplasmic expression of menin was mainly present (11/12) in the phMEN 1. In the SA group, there was no staining in 1 case; nuclear expression was detected in 6/14 cases. The phMEN  1 group showed significantly higher cytoplasmic expression of menin than the gMEN  1 group (p = 0.006). The gMEN 1 group also differed from the SA group (p = 0.012). There were no statistically significant differences between the phMEN 1 and SA groups (p = 0.049). CONCLUSION: It was revealed that the menin expression, in general, is retained in phMEN 1 and SA groups, although with different localization in the cell structure (nucleus and / or cytoplasm). At the same time, the expression of menin varies greatly in patients with gMEN 1. According to the data obtained, it can be assumed that the pathogenesis of PA in phMEN 1 and SA may have similarities; however, there could be factors contributing to the appearance of several tumors of the endocrine glands in one person with phMEN 1. To understand this process, it is necessary to further study the genes associated with MEN 1, epigenetic factors, signaling pathways in which menin is involved.

[A series of clinical cases of familial hypocalciuric hypercalcemia syndrome].

Familial hypocalciuric hypercalcemia (FHH) - rare disease with predominantly autosomal dominant inheritance. FHH typically develops due to a heterozygous inactivating mutation in the calcium-sensitive receptor gene (CASR), less commonly due to heterozygous mutations in GNA11 and AP2S1. CASR mutations lead to an increase in the threshold for calcium sensitivity, which requires a higher concentration in serum to reduce the release of PTH. These changes are accompanied by an increase of calcium and magnesium reabsorption in the proximal tubules, which leads to hypercalcemia and hypocalciuria. Basically, FHH may be asymptomatic or accompanied by mild hypercalcemia. FHH doesn't require surgical treatment, unlike primary hyperparathyroidism (PHPT), therefore, differential diagnosis of these two conditions is extremely important. In addition, immediate relatives of a proband with FHH also require the exclusion of disease inheritance. We analyzed a series of clinical cases with a genetically confirmed diagnosis of FHH. Our clinical cases indicate a variety of clinical manifestations and the difficulties of differential diagnosis with PHPT.

[Hereditary Cushing's syndrome caused by primary bilateral macronodular adrenal hyperplasia due to ARMC5 mutation with concomitant primary hyperparathyroidism: the first known case in Russia].

Primary bilateral macronodular adrenal hyperplasia (PBMAH), a genetically heterogeneous disease, is a rare cause of Cushing's syndrome. Until recently, few cases were attributed to mutations in known genes. However, in 2013, ARMC5, a newly discovered tumor suppressor gene, was identified. Further studies have shown that mutations in the ARMC5 gene are found in 25-55% of all PBMAH cases. This article describes a clinical case of hereditary Cushing's syndrome caused by PBMAH in a 37-year old patient. The patient's family history is remarkable for the presence of Cushing's syndrome and PBMAH in the patient's mother. Bilateral adrenalectomy was performed as the treatment of choice. Genetic analysis using whole-exome sequencing confirmed the hereditary cause of the disease, revealing a germline heterozygous mutation in the ARMC5 gene. The patient also had concomitant mild primary hyperparathyroidism, which had not been observed before in genetic carriers with the ARMC5 mutation.

[CDC73 mutations in young patients with primary hyperparathyroidism: A description of two clinical cases]. / Mutatsii v gene CDC73 u molodykh patsientok s pervichnym giperparatireozom (opisanie dvukh klinicheskikh sluchaev).

The article describes two clinical cases of severe primary hyperparathyroidism (PHPT) caused by parathyroid carcinoma in young female patients who underwent molecular genetic testing to rule out the hereditary forms of PHPT. In both patients, heterozygous germline nonsense mutations of tumor suppressor gene CDC73 encoding parafibromin (p.R91X and p.Q166X) were identified using next-generation sequencing with Ion Torrent Personal Genome Machine (Thermo Fisher Scientific - Life Technologies, USA). It is the first description of CDC73 mutations in Russia, one of the mutations is described for the first time in the world. Identification of germline mutations in the CDC73 gene in patients with PHPT necessitates regular lifelong screening for other manifestations of hyperparathyroidism-jaw tumor syndrome (HPT-JT), PHPT recurrence due to parathyroid carcinoma as well, and identification of mutation carriers among first-degree relatives.