Experience with the targeted next-generation sequencing in the diagnosis of hereditary hypophosphatemic rickets.

OBJECTIVES: Hereditary Hypophosphatemic Rickets (HHR) is a heterogeneous group of disorders characterized by hypophosphatemia. Although the X-linked dominant HHR is the most common form, the genetic etiology of HHR is variable. Recently, developed next-generation sequencing techniques may provide opportunities for making HHR diagnosis in a timely and efficient way. METHODS: We investigated clinical and genetic features for 18 consecutive probands and their 17 affected family members with HHR. All patient's clinical and biochemical data were collected. We first analyzed a single gene with Next-generation sequencing if the patients have a strong clue for an individual gene. For the remaining cases, a Hypophosphatemic Rickets gene panel, including all known HHR genes by Next-generation sequencing, was employed. RESULTS: We were able to diagnosis all of the consecutive 35 patients in our tertiary care center. We detected nine novel and 10 previously described variants in PHEX (9; 50%), SLC34A3 (3; 17%), ENPP1 (3; 17%), SLC34A1 (1; 5%), CLCN5 (1; 5%), and DMP1 (1; 5%). CONCLUSIONS: To delineate the etiology of HHR cases in a cost and time-efficient manner, we propose single gene analysis by next-generation sequencing if findings of patients indicate a strong clue for an individual gene. If that analysis is negative or for all other cases, a Next-generation Sequence gene panel, which includes all known HHR genes, should be employed.

21-Hydroxylase deficiency: Mutational spectrum and Genotype-Phenotype relations analyses by next-generation sequencing and multiplex ligation-dependent probe amplification.

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD) is autosomal recessive disorder of cortisol biosynthesis. Genetic defects in CYP21A2 cause 21OHD. The aim of this study was to determine spectrum of mutations in CYP21A2 in a large cohort and analyze the genotype-phenotype correlation to assess predictive characteristics of genotype. We investigated a total of 113 patients with 21OHD. Next-generation sequencing and Multiplex ligation-dependent probe amplification of the CYP21A2 gene were performed in patients and their parents. The genotypes were categorized into Groups 0, A, B, and C according to the residual 21-hydroxylase activities. In this study, the group A was divided into two subgroups as A1 and A2. Three novel variants were found. The genotype-phenotype correlation of the mutation classification was 91.5%. Positive predictivity of subgroups A1 was higher than groups A and subgroups A2. Our study reports genotype-phenotype correlations in the largest 21OHD cohort in Turkey. This correlation sustained when we analyzed our data in combination with metadata from other published studies. This study confirms that CYP21A2 genotyping with next-generation sequencing and MLPA can accurately and reliably confirm the diagnosis of 21OHD. We propose a new classification by dividing group A into two new subgroups to better predict the phenotype. In light of this very high genotype-phenotype correlation, with their ever-increasing availability, declining cost, and turnaround time, we propose that molecular genetic studies can be more economical and practical alternative to the current initial diagnostic laboratory studies based on assays of intermediary steroid metabolites.

Hyperphosphatemic Familial Tumoral Calcinosis in Two Siblings with a Novel Mutation in GALNT3 Gene: Experience from Southern Turkey

Inactivating autosomal recessive mutations in fibroblast growth factor 23 (FGF23), klotho (KL) and polypeptide N-acetylgalactosaminotransferase 3 (GALNT3) genes lead to a rare disorder, hyperphosphatemic familial tumoral calcinosis (HFTC). Patients with HFTC present with hyperphosphatemia and tumor like soft tissue calcifications. Although 78% of patients develop their first symptoms between the ages of 2-13 years, diagnosis is usually delayed until adulthood. Some individuals with the same genetic defect develop a condition named hyperphosphatemic hyperostosis syndrome. Herein we report two siblings suffering from periarticular, warm, hard and tender subcutaneous masses. Subcutaneous calcifications were present on X-ray and biopsy results were consistent with calcinosis in both patients. Laboratory results showed marked hyperphosphatemia and elevated renal tubular phosphate reabsorption rates, normal renal function tests and normal serum 25-hydroxyvitamin D levels. Thus, we suspected HFTC and performed next generation sequencing for the GALNT3 gene, reported as the most frequent cause. A novel homozygote P85Rfs*6 (c.254_255delCT) mutation in GALNT3 was identified in both siblings. Our report adds two new patients to the literature about this rare genetic disease and suggests that small deletions in the GALNT3 gene may be related with HFTC phenotype.

Prevalence and associated phenotypes of PLXNA1 variants in normosmic and anosmic idiopathic hypogonadotropic hypogonadism.

Idiopathic hypogonadotropic hypogonadism (IHH) can be divided into two major forms, normosmic IHH and Kallmann syndrome (KS). Genetic mutations are responsible for the majority of IHH. PLXNA1 has recently been implicated in the GnRH neuron migration and the etiology of KS. We aimed to investigate the prevalence and associated phenotypes of PLXNA1 variants in a large cohort of IHH patients. We screened the whole exome data of 215 IHH patients in a single center for causative PLXNA1 variants. Our studies showed eight novel (p.Arg836His, p.Lys1451Arg, p.Val287Met, p.Val536Ile, p.Ser1850Arg, p.Ile1701Val, p.Arg319Trp, and p.Pro485Leu) and two previously described (p.Arg528Trp and p.Gly720Glu) heterozygous PLXNA1 variants in nine affected individuals from seven unrelated families. Only three of nine patients were anosmic (KS) while the remaining patients showed normal olfactory function (nIHH). Seven of nine patients (77.7%) harbored additional one or two variants in other nIHH/KS-associated genes, including PROKR2, IGSF10, HS6ST1, SEMA3E, CCDC141, FGFR1, NRP1, POLR3A, and SRA1. Our findings indicate that PLXNA1 variants cause not only anosmic but also normosmic IHH with a relatively high prevalence (3.9%). Heterozygous missense PLXNA1 variants appear to be involved together with other IHH gene variants in bringing about the IHH disease phenotype.

Management of Thyrotoxicosis in Children and Adolescents: A Turkish Multi-center Experience

Objective: To determine the demographic and biochemical features of childhood and juvenile thyrotoxicosis and treatment outcome. Methods: We reviewed the records of children from 22 centers in Turkey who were diagnosed with thyrotoxicosis between 2007 to 2017. Results: A total of 503 children had been diagnosed with thyrotoxicosis at the centers during the study period. Of these, 375 (74.6%) had been diagnosed with Graves' disease (GD), 75 (14.9%) with hashitoxicosis and 53 (10.5%) with other less common causes of thyrotoxicosis. The most common presenting features in children with GD or hashitoxicosis were tachycardia and/or palpitations, weight loss and excessive sweating. The cumulative remission rate was 17.6% in 370 patients with GD who had received anti-thyroid drugs (ATDs) for initial treatment. The median (range) treatment period was 22.8 (0.3-127) months. No variables predictive of achieving remission were identified. Twenty-seven received second-line treatment because of poor disease control and/or adverse events associated with ATDs. Total thyroidectomy was performed in 17 patients with no recurrence of thyrotoxicosis and all became hypothyroid. Ten patients received radioiodine and six became hypothyroid, one remained hyperthyroid and restarted ATDs and one patient achieved remission. Two patients were lost to follow up. Conclusion: This study has demonstrated that using ATDs is the generally accepted first-line approach and there seems to be low remission rate with ATDs in pediatric GD patients in Turkey.

Efficiency of Single Dose of Tolvaptan Treatment During the Triphasic Episode After Surgery for Craniopharyngioma

Inappropriate antidiuretic hormone syndrome (SIADH) may develop after intracranial surgery. SIADH in the pediatric age group is usually encountered in patients with an intracranial mass both before and after surgery. Fluid restriction is the standard therapy in SIADH. However, a resistant, hyponatremic pattern may be encountered in some cases. Vaptans have been recently introduced for treatment of hyponatremia due to SIADH. There is inadequate data concerning tolvaptan treatment in pediatric patients. We present a 13 year-old female with SIADH of triphasic episode who was transferred to our clinic after surgery for craniopharyngioma. Resistant hyponatremia did not resolve despite fluid restriction and hypertonic saline support. The patient responded rapidly to a single dose of tolvaptan, with no adverse effect, which resulted in successful control of her SIADH.

Molecular genetic studies in a case series of isolated hypoaldosteronism due to biosynthesis defects or aldosterone resistance.

BACKGROUND AND AIM: Hypoaldosteronism is associated with either insufficient aldosterone production or aldosterone resistance (pseudohypoaldosteronism). Patients with aldosterone defects typically present with similar symptoms and findings, which include failure to thrive, vomiting, hyponatremia, hyperkalemia and metabolic acidosis. Accurate diagnosis of these clinical conditions therefore can be challenging. Molecular genetic analyses can help to greatly clarify this complexity. The aim of this study was to obtain an overview of the clinical and genetic characteristics of patients with aldosterone defects due to biosynthesis defects or aldosterone resistance. DESIGN AND PATIENTS: We investigated the clinical and molecular genetic features of 8 consecutive patients with a clinical picture of aldosterone defects seen in our clinics during the period of May 2015 through October 2017. We screened CYP11B2 for aldosterone synthesis defects and NR3C2 and the three EnaC subunits (SCNN1A, SCNN1B and SCNN1G) for aldosterone resistance. RESULTS: We found 4 novel and 2 previously reported mutations in the genes CYP11B2, NR3C2, SCNN1A and SCNN1G in 9 affected individuals from 7 unrelated families. CONCLUSION: Molecular genetic investigations can help confidently diagnose these conditions and clarify the pathogenicity of aldosterone defects. This study may expand the clinical and genetic correlations of defects in aldosterone synthesis or resistance.

Electroconvulsive therapy in pregnant patients.

OBJECTIVES: In this study, the aim was to evaluate the clinical characteristics of patients that received electroconvulsive therapy (ECT) during pregnancy due to psychiatric disorders, evaluate the safety and efficacy of ECT in pregnant women, and evaluate the overall status of mothers and babies during the postpartum period. METHODS: The study included 33 patients who were admitted as inpatients with the indication of ECT due to pregnancy and concurrent psychiatric disorders. RESULTS: Upon ECT administration, a complete response to treatment was seen in 84.21% of patients with major depression (n=16), a partial response to treatment in 15.78% of patients (n=3), a complete response to treatment in 91.66% of patients with bipolar disorder (n=11), a partial response to treatment in 8.33% of the patients(n=1), and a full response to treatment in 50% of patients with schizophrenia (n=1) and a partial response to treatment in 50% of patients with schizophrenia (n=1) were obtained. We had after birth information of 27 infants from total 33. It was learned that two of them had disease, one was stillbirth and 24 of them did not have any health problems. CONCLUSIONS: ECT administration during pregnancy to treat psychiatric disorders was found to be an effective treatment method. No risk of preterm birth in mothers treated with ECT during pregnancy was detected.

Maintenance therapy with electroconvulsive therapy in a patient with a codiagnosis of bipolar disorder and obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is defined as the most commonly seen anxiety disorder accompanying the bipolar disorder, and this concomitance causes the difficulties in the therapy. Although electroconvulsive therapy (ECT) is efficient in both manic and depressive episodes of the bipolar disorder, it is considered as a therapeutic option in cases of OCD with depression comorbidity. In this article, we aimed to present a case in which depressive episode of bipolar disorder and OCD comorbidity were present; both depressive and OCD symptoms were resolved using ECT. Symptoms of both diseases recurred after the discontinuation of ECT, and well-being sustained with maintenance ECT.