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The enzyme 17-β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) catalyzes the biosynthesis of testosterone (T) from Δ4-androstenedione, and plays an important role in the final steps of androgen synthesis. 17β-HSD3 deficiency originates from mutations in the HSD17B gene, causing an autosomal recessive 46,XY sex developmental disorder (DSD). Patients with 46,XY karyotype can exhibit a wide phenotypic spectrum, varying from complete external female genitalia to male genitalia with hypospadias. Here we report a case of 17β-HSD3 deficiency diagnosed in the infantile period who was later found to have a novel HSD17B3 gene variation. The 14-month old patient, who exhibited a female phenotype, presented with a bilateral lump in the inguinal area. Imaging revealed bilateral testicular gonads in the inguinal area. Hormonal evaluation showed low levels of basal and stimulated serum T, a high level of androstenedione (A), and a low T/A ratio. Chromosomal analysis showed 46,XY karyotype. Sequence analysis of the HSD17B3 gene revealed a c.673_1G>C homozygous class 2 (splice site) variation in intron 9. The consanguineous parents were sequenced, and both were heterozygous for the same mutation. This variation has not been previously reported in the literature. In conclusion, a 46,XY DSD should be considered in patients with a female phenotype who exhibit gonad(s) in the inguinal area at an early age. Furthermore, in patients with insufficient T synthesis and high levels of androstenedione, 17β-HSD3 should be considered, and molecular analysis should be done for a definitive diagnosis and subsequent genetic counseling.

An activating variant of the thyroid stimulating hormone receptor (TSHR) gene is one of the rare causes of neonatal hyperthyroidism. This disorder may occur as a result of an autosomal dominant inheritance or sporadically through de novo variation. Here we present a case of neonatal onset congenital non-autoimmune hyperthyroidism (NAH) with a sporadic germline activating TSHRV656F variant. A female infant with tachycardia, who was transferred due to hyperthyroidism in the first week of life, displayed no other symptoms or signs. The patient's mother did not have Graves' disease, and TSHR stimulating antibodies were not present in the mother or baby. Imaging showed thyroid gland hyperplasia and left ventricular hypertrophy, the patient was subsequently put on methimazole treatment. After six months undergoing treatment, a heterozygous p.Val656Phe (V656F) (c.1966G>T) variant was detected on exon 10 of the TSHR gene. The variant was not identified in the mother and father, so the case was assumed to be sporadic. In conclusion, although the literature describes V656F variant as a somatic variant in children and adults with toxic thyroid nodule(s) that results in the structural activation of the TSH receptor, no previous cases of neonatal hyperthyroidism due to TSHRV656F variant have been reported. This study is the first case review that highlights the relationship between TSHRV656F variant and neonatal onset NAH.

Objective:Primary adrenal insufficiency (PAI) is a rare but potentially life-threatening condition. In childhood, PAI is usually caused by monogenic diseases. Although congenital adrenal hyperplasia (CAH) is the most common cause of childhood PAI, numerous non-CAH genetic causes have also been identified.Methods:Patients aged 0-18 years and diagnosed with PAI between 1998 and 2019 in a tertiary care hospital were retrospectively evaluated. After the etiologic distribution was determined, non-CAH PAI patients were evaluated in detail.Results:Seventy-three PAI patients were identified. The most common etiology was CAH (69.9%, n=51). Non-CAH etiologies accounted for 30.1% (n=22) and included adrenoleukodystrophy (ALD; n=8), familial glucocorticoid deficiency (n=3), Triple A syndrome (n=5), autoimmune adrenalitis (n=1), adrenal hypoplasia congenital (n=1), IMAGe syndrome (n=1), and other unknown etiologies (n=3). The median age at the time of AI diagnosis for non-CAH etiologies was 3.52 (0.03-15.17) years. The most frequent symptoms/clinical findings at onset were hyperpigmentation of skin (81.8%), symptoms of hypoglycemia (40.9%), and weakness/fatigue (31.8%). Hypoglycemia (50.0%), hyponatremia (36.4%) and hyperkalemia (22.7%) were prominent biochemical findings. Diagnosis of specific etiologies were proven genetically in 13 of 22 patients. A novel p.Q301* hemizygous frameshift mutation of the DAX1 gene was identified in one patient.Conclusion:Etiology was determined in 86.3% of children with non-CAH PAI through specific clinical and laboratory findings with/ without molecular analysis of candidate genes. ALD was the most common etiology. Currently, advanced molecular analysis can be utilized to establish a specific genetic diagnosis for PAI in patients who have no specific diagnostic features.

INTRODUCTION: Idiopathic hypogonadotropic hypogonadism (IHH) is classified into two groups-Kalman syndrome and normosmic IHH (nIHH). Half of all cases can be explained by mutations in >50 genes. Targeted gene panel testing with nexrt generation sequencing (NGS) is required for patients without typical phenotypic findings. The aim was to determine the genetic etiologies of patients with IHH using NGS, including 54 IHH-associated genes, and to present protein homology modeling and protein stability analyzes of the detected variations. METHODS: Clinical and demographic data of 16 patients (eight female), aged between 11.6-17.8 years, from different families were assessed. All patients were followed up for a diagnosis of nIHH, had normal cranial imaging, were without anterior pituitary hormone deficiency other than gonadotropins, had no sex chromosome anomaly, had no additional disease, and underwent genetic analysis with NGS between the years 2008-2021. Rare variants were classified according to the variant interpretation framework of the American College of Medical Genetics and Genomics (ACMG)/Association for Molecular Pathology. Changes in protein structure caused by variations were modeled using RoseTTAFold and changes in protein stability resulting from variation were analyzed. RESULTS: Half of the 16 had no detectable variation. Three (18.75%) had a homozygous (pathogenic) variant in the GNRHR gene, one (6.25%) had a compound heterozygous [likely pathogenic-variants of uncertain significance (VUS)] variant in PROK2 and four (25%) each had a heterozygous (VUS) variant in HESX1, FGF8, FLRT3 and DMXL2. Protein models showed that variants interpreted as VUS according to ACMG could account for the clinical IHH. DISCUSSION AND CONCLUSION: The frequency of variation detection was similar to the literature. Modelling showed that the variant in five different genes, interpreted as VUS according to ACMG, could explain the clinical IHH.

Variants of the melanocortin-4 receptor (MC4R) gene are the most common cause of monogenic obesity. It has been shown that, while obesity cannot be controlled with diet and exercise, glucagon-like-peptide-1 receptor agonists (GLP-1 RA) provide weight loss in the short term. In this paper, our experience with liraglutide treatment in an adolescent patient carrying a MC4R gene variant is presented. A female patient was admitted first at the age of 12.5 years with a complaint of progressive weight gain. She had marked excess of appetite since infancy. On physical examination of the pubertal female patient with a body mass index (BMI) of 36.1 kg/m2 (3.48 standard deviation score), there was no pathological finding except diffuse acanthosis nigricans. Laboratory examinations revealed only insulin resistance. Weight loss was not achieved with lifestyle changes, metformin and orlistat treatments. On genetic examination, a sporadic heterozygous c.206T>G(p.I69R) variant that had been reported previously, was found in MC4R gene. Treatment with the GLP-1 RA, liraglutide, was initiated and a 19.2% reduction was achieved in the body weight and BMI at the end of 32 weeks. However, the patient, whose treatment compliance was disrupted due to significant gastrointestinal complaints, returned to her former weight within a few months (13 weeks) after treatment was stopped. In this case with a known pathogenic variant in MC4R gene, decrease of appetite and weight loss were achieved with liraglutide treatment, but side-effects of this treatment led to discontinuation of therapy. In such cases, there is need for effective and tolerable treatment options.