Nicotinamide nucleotide transhydrogenase (NNT) deficiency causes primary adrenal insufficiency (PAI) and possibly some extra-adrenal manifestations. A limited number of these patients were previously described. We present the clinical and genetic characteristics of three family members with a biallelic novel pathogenic variant in the NNT gene. The patients were followed until the ages of 21.6, 20.2, and 4.2 years. PAI was diagnosed in the eldest two brothers after an Addisonian crisis and the third was diagnosed at the age of 4.5 months in the asymptomatic stage due to the genetic screening of family members. Whole exome sequencing with a targeted interpretation of variants in genes related to PAI was performed in all the patients. The urinary steroid metabolome was determined by gas chromatography–mass spectrometry in the asymptomatic patient. The three patients, who were homozygous for c.1575dup in the NNT gene, developed isolated glucocorticoid deficiency. The urinary steroid metabolome showed normal excretion of cortisol metabolites. The adolescent patients had slow pubertal progression with low–normal testicular volume, while testicular endocrine function was normal. Bone mineral density was in the range for osteopenia in both grown-up siblings. Echocardiography revealed no structural or functional heart abnormalities. This article is among the first with a comprehensive and chronologically-detailed description of patients with NNT deficiency.
16 December 2021 in Molecular Genetics and Metabolism Reports
Tyrosinemia type 1 (HT1) is an inborn error of tyrosine catabolism that leads to severe liver, kidney, and neurological dysfunction. Newborn screening (NBS) can enable a timely diagnosis and early initiation of treatment.
Background and Objectives. Familial non-autoimmune autosomal dominant hyperthyroidism (FNAH) is a rare cause of childhood hyperthyroidism. It is caused by the thyroid-stimulating hormone receptor (TSHR) gene variants. So far, only around 40 families with FNAH have been reported. Patients with activating TSHR variants demonstrated the same classical signs and symptoms of hyperthyroidism as seen in patients with Graves’ disease. Since 2012, ablative therapy is recommended to avoid relapses of hyperthyroidism and its consequences. Case Presentation. We presented a young adult male patient with a novel heterozygous TSHR disease-causing variant p.Arg418Lys (c.1253G>A) in the exon 10, who presented with a mild but progressive FNAH, with a follow-up since infancy. Discussion. Constantly suppressed TSH, including during the euthyreosis in childhood and hypothyreosis after iodine ablation therapy, suggested central dysregulation of the TSH secretion.
Fetal and neonatal thyrotoxicosis occurs in up to 5% of pregnancies in mothers with Graves’ disease (GD). This condition is caused by stimulating antibodies against the thyrotropin receptor (TRAbs) that cross the placenta and may stimulate the fetal thyroid, typically in the second half of pregnancy. GD is often treated with radioiodine, resulting in hypothyroidism in most patients, but TRAbs can persist for several years. Even if a pregnant mother is hypothyroid after radioiodine therapy or surgery, her TRAbs can still, although rarely, induce fetal hyperthyroidism. In this review, we first present two cases of neonatal hyperthyroidism in mothers with GD who became hypothyroid after prior radioiodine therapy, identified through a 10-year analysis of the National Perinatal System in Slovenia. Based on these cases, we provide an overview of existing data on this rare clinical condition in neonates. We also discuss the underlying mechanisms and clinical outcomes based on currently available data. In conclusion, our review highlights the importance of careful monitoring during pregnancy in all women with GD, even in those well managed after radioiodine therapy or surgery.
Rare diseases (RDs), with distinctive and complex features, pose a serious public health concern and represent a considerable challenge for the Slovenian healthcare system. One of the potential approaches to tackling this problem and treating patients with RDs in a quality and effective manner is to form an RD ecosystem. This represents a functional environment that integrates all stakeholders, procedures, and relationships required for the coordinated and effective treatment of patients. This paper explores the current situation in the field of RDs, especially in light of the proposed ecosystemic arrangement, and provides an outline for the design of an RD ecosystem in Slovenia. The research applies a case-study design, where focus groups are used to collect evidence from the field, assess the state of affairs, and generate ideas. Structured focus group discussions were conducted with preeminent experts affiliated with the leading institutions in the field of RDs in Slovenia. Analyses and interpretations of the obtained data were carried out by means of conventional content analysis. Setting up an RD ecosystem in Slovenia would lead to significant benefits for patients, as it could promote the coordination of healthcare treatment and facilitate extensive monitoring of the treatment parameters and outcomes. A well-organized RD ecosystem could garner considerable systemic benefits for evidence-informed policymaking, a better utilization of resources, and technological innovation. Delivering quality healthcare in this complex field is largely reliant on the effective integration and collaboration of all entities within the RD ecosystem, the alignment of related systemic factors, and the direction of healthcare services to support the needs and well-being of patients with RDs.
Blood phenylalanine-to-tyrosine (Phe/Tyr) ratio is an important indicator of metabolic control in phenylketonuria patients. We present the data that highlights the role of Phe/Tyr-ratio in the evaluation of tetrahydrobiopterin (BH4)-responsiveness in patients with hyperphenylalaninemia. Our data complements the results from the original research article by Tansek et al., 2012 [1]. We performed a BH4-loading test in 32 patients after four days of increased protein intake (2000 mg/kg body weight). Blood sampling was performed 96, 72, 48, 24, 16 h, and moments before oral administration of BH4 in a dose of 20 mg/kg body weight. Additional blood samples were collected 8 and 24 h after its administration. Phenylalanine (Phe) and Tyrosine (Tyr) levels were determined from dried blood spots by tandem mass spectrometry. Phe/Tyr-ratio reached a plateau after three days of increased dietary protein intake. Fifteen patients (47%) responded to BH4, defined as a decrease of Phe-of at least 30% after 24 h of BH4 administration. Phe/Tyr-ratios were significantly higher in non-responders compared to responders. In the responder group, Phe/Tyr-ratios decreased in average of 67% (p = 0.001) and 45% (p = 0.001) after 8 and 24 h of BH4 administration, respectively. Phe/Tyr-ratio decreased after 8 h of drug administration also in the non-responder group, but not 24 h after administration.