Defect In Synthesis Research Articles

BACH1 regulates erythrophagocytosis and iron-recycling in β-thalassemia.

Macrophages play essential roles in erythrophagocytosis and iron recycling. β-thalassemia is characterized by a genetic defect in hemoglobin synthesis, which increases the rate of iron recycling. We previously showed that reduced expression of the BTB and CNC homolog 1 (BACH1) gene leads to increased phagocytosis of abnormal RBCs by activated monocytes. However, the mechanisms underlying this abnormal RBC clearance remained unclear. Herein, the spleen and bone marrow cells of β-thalassemic mice were examined for erythrophagocytosis CD markers and iron-recycling genes. Higher expression levels of CD47 and CD163 on RBCs and macrophages, respectively, were observed in β-thalassemic mice than in wild-type cells. The decreased expression of BACH1 caused an increase in Nrf2, Spic, Slc40a1, and HMOX1 expression in splenic red pulp macrophages of thalassemic mice. To investigate BACH1 regulation, a macrophage cell line was transfected with BACH1-siRNA. Decreased BACH1 expression caused an increase in CD163 expression; however, the expression levels were lower when the cells were cultured in media supplemented with β-thalassemia/HbE patient plasma. Additionally, the iron recycling-related genes SPIC, SLC40A1, and HMOX1 were significantly upregulated in BACH1-suppressed macrophages. Our findings provide insights into BACH1 regulation, which plays an important role in erythrophagocytosis and iron recycling in thalassemic macrophages.

Persistence of foetal testicular features in patients with defective androgen signalling.

Congenital defects of androgen synthesis or action in 46, XY individuals can result in impaired virilisation, despite the apparent testicular development. In a recent case report of a young adult with complete androgen insensitivity syndrome (CAIS), tumorous gonadal tissue was shown to express HSD17B3 in Sertoli cells (SCs) and not in Leydig cells (LCs). This expression pattern differs from the typical adult human testis and resembles foetal mouse testis, suggesting an underlying testicular development and function defect. Here, we investigate the effect of altered androgen signalling in gonads from five 46, XY individuals with defects in androgen synthesis or action. Gonadal tissue sections from four patients with CAIS, one with CYP17A1 deficiency, and one control were immunostained for LC developmental and steroidogenic markers. The expression of some of these markers during development was investigated by reanalysing previously published single-cell RNA sequencing (scRNA-seq) data from normal human testicular tissues. All gonadal tissues from the patients show exclusive expression of HSD17B3 in SCs and expression of the foetal/immature LC marker DLK1 in a subset of LCs, suggesting an androgen-dependent differentiation defect of adult SCs and LCs. Furthermore, reanalysis of scRNA-seq data reveals an expression of HSD17B3 in foetal and neonatal SCs that is downregulated in adult SCs. Androgen signalling may affect the differentiation of adult but possibly not foetal SCs or LCs and may induce a shift of testosterone production from the tubular compartment in the foetal phase to the interstitial compartment in the adult phase.

β-Thalassemia in childhood: Current state of health in a high-income country.

β-thalassemia is an haemoglobinopathy characterized by a defective synthesis of the β-globin chain. To assess the current state of health of paediatric patients with β-thalassemia, data from the French national registry regarding children born between 2005 and 2020 with β-thalassemia intermedia (TI) or major (TM) were collected. A total of 237 patients (median age 7.1 years at last visit) were analysed, of whom 156 (65.8%) were born in France and 162 (68.4%) had a TM phenotype. The probability of survival for children with TM born in France was 98.3% at 15 years. Fifty-four (22.8%) children received a haematopoietic stem cell transplant with a success rate of 88.8%. Hepatic and cardiac iron overload monitoring in non-transplanted patients showed moderate overload in 15.7% (18/115) and 7.1% (7/99) of cases, respectively, while clinical complications were found in only 4 patients with TM (hepatic in 3 cases). At last visit, mean ferritinemia was 1293 ng/ml (±759). Overall, less than 10% of children underwent splenectomy. No significant impact of the disease on growth or academic achievement was observed. Deferasirox was the main first-line chelator, prescribed in 78.2% of cases, with side effects reported in 11.7% of instances.

Simple-Virilizing Congenital Adrenal Hyperplasia – A Rare Case Report

Abstract Simple-virilizing congenital adrenal hyperplasia (SV-CAH) is an inherited condition which transmission is autosomal recessive due to complete or partial enzyme deficiency which leads to defective cortisol synthesis. It involves five enzyme-linked steps. Insufficiency of any enzyme leads to different types of CAH. It can be classified into classic and nonclassic. Classic has two subtypes – salt wasting and simple-virilizing type. This case report of a 3½-year-old boy showing an increase in growth of genitals and increase in pigmentation of the skin. A probable diagnosis of virilizing CAH or precocious puberty was made. On laboratory investigation, there was a decrease in the level of cortisol and grossly raised level of 17-hydroxyprogesterone. This condition was diagnosed with SV-CAH after confirmation with laboratory parameters. The patient was managed accordingly. The aim of the treatment was to correct the level of cortisol and maintain balance of electrolytes. Hence, the patient was treated with hydrocortisone and fludrocortisone and discharged with advice to continue the same treatment.

Uso de placa de polimetilmetacrilato (PMMA) no tratamento de craniosquise associada à meningocele em uma bezerra girolando: relato de caso

Abstract Most genetic diseases affect purebred animals and are inherited as recessive genes. Cranioschisis refers to dysraphism, which occurs in the midline of the skull due to failure to close the cranial symphysis, which can lead to herniation of the meninges filled with cerebrospinal fluid (meningocele), where there is usually a projection of the meningeal tissue. Diagnosis is performed based on clinical examination, characteristic anatomopathological data, and complementary imaging tests. The surgical approach for correction of cranioschisis is the only described as a therapeutic solution and is indicated in cases in which the cranial synthesis defect does not allow for brain protrusion and there is only the occurrence of meningocele, in addition to the absence of severe signs of neurological alteration. This paper reports a case of the use of polymethylmethacrylate (PMMA) plaque to treat cranioschisis associated with meningocele in a Girolando heifer. The surgical opening of the frontonasal sacculation allowed draining a total liquid content of 488 mL, inspection, and suture of the envelope membrane. APMMA plaque, molded to the bone surface and anchored in the adjacent soft tissue, was used to cover the evidenced frontonasal bone opening. Despite the unfavorable prognosis of the disease, the cranioplasty surgery for the treatment of cranioschisis associated with meningocele using PMMA plaque obtained satisfactory results relative to the quality and maintenance of this animal’s life, evaluated at 19 months postoperatively.

Relationship between serum ferritin and parathyroid function in adult male patients with transfusion dependent thalassemia

Background: Thalassemia is a genetic disorder of defective hemoglobin synthesis. In transfusion dependent thalassemia (TDT), iron overload is caused by repeated blood transfusion for a long time. This increased iron is deposited in body tissue and may lead to endocrine dysfunction. Objective: To evaluate the relationship between serum ferritin and parathyroid dysfunction in adult male patients with TDT. Methods: It was a cross sectional study which was conducted from March 2018 to February 2019 in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka. For this study, 35 TDT male patients aged 18 to 40 year, were considered as study group and 35 age and sex matched apparently healthy subjects were considered as control group. The outpatient department of Hematology and Transfusion Medicine was the point of collection of study group. Parathyroid function was assessed by plasma intact para thyroid hormone (iPTH), serum total calcium and serum inorganic phosphate. Plasma iPTH and serum ferritin levels were estimated by Electrochemiluminescence Immunoassay method using automated analyzer. Serum total calcium and serum inorganic phosphate levels were estimated by colorimetric method using automated analyzer. Independent sample t test and Pearson’s correlation coefficient (r) test were applied for statistical analysis using SPSS version 16. Results: In this study, serum ferritin level was significantly (p <0.001) higher in patients with TDT than that of healthy control. Correlation analysis showed negative correlation of serum ferritin with plasma iPTH and serum corrected calcium and positive correlation with serum inorganic phosphate in patients with TDT. Among them correlation with serum corrected calcium and inorganic phosphate were statistically significant (p <0.05). Conclusion: This study concluded that TDT may be associated with elevated iron status which is inversely related with parathyroid function. J Bangladesh Soc Physiol. 2022, June; 17(1): 1-5

Evaluation of Hepatic Enzymes in major β-thalassemic Patients using Deferasirox

Abstract β-thalassemia major is a genetic disease that causes sever defect in normal hemoglobin synthesis. The patients with β-thalassemia major need periodic blood transfusions that can result in accumulation of body iron, so treatment with iron chelating agent is required. Complications of this iron overload affecting many vital organs, including the liver. The aim of this work was to evaluate liver enzymes in β -thalassemia major patients with deferasirox versus without it. Two groups of β-thalassemia major patients were involved in this study named group A; 40 β-thalassemia patients of blood transfusion dependent without deferasirox, group B; 40 β-thalassemia patients of blood transfusion dependent on deferasirox. In addition to group C, 40 normal subjects as a control group. Samples of serum were obtained from all participants to be tested for alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase and ferritin. The biochemical data of the patients on blood transfusion without deferasirox showed significant increases in the mean serum levels of aminotransferases and ferritin in comparison with control. Whereas the patients on blood transfusion with deferasirox exhibit significant increases in the means serum levels of alkaline phosphatase activity and ferritin in comparison with control. Iron overload may cause liver injury, shown by significant increases of; ALT and AST activities and elevated ferritin level in serum of transfusion dependent patients of β-thalassemia major. Administration of deferasirox for β-thalassemia major patients causes elevation of serum ALP activity and ferritin level.

The Role of Serum Lactate Dehydrogenase in Etiological Diagnosis of Macrocytic Anemia

Background: Macrocytic anemia is common and is characterized by decreased hemoglobin levels with elevated Mean Corpuscular Volume (MCV), due to a range of diseases and divided into Megaloblastic and Non-megaloblastic anemia. Serum vitamin B12 and folic acid tests are usually performed but they are limited by their low sensitivity and specificity. To confirm diagnosis of macrocytic anemia bone marrow examination is required but it is invasive procedure. Vitamin B12 and/or B9 deficiency leads to a defect in DNA synthesis leading to ineffective erythropoiesis and intramedullary hemolysis in patients of megaloblastic anemia, this leads to increased serum LDH (Lactate Dehydrogenase) and unconjugated bilirubin. Aims of study: This study was carried out to evaluate the role of serum LDH in the distinction between megaloblastic and non-megaloblastic anemia, and to study the correlation between serum LDH and MCV Patient and Methods: The study included 60 patients with non-regenerative macrocytic anemia (We exclude patients with regenerative macrocytic anemia because elevated reticulocytes leads us to hymolysis anemia or bleeding and it’s not a diagnostic problem(. Complete blood count, biochemical investigation, peripheral blood examination, reticulocyte count, bone marrow examination was performed in all cases Results: The most common cause of macrocytic anemia was Megaloblastic anemia (65%). The other causes were primary bone marrow disorders (35%). There was a significant difference in the mean values of serum LDH and MCV between two groups ( megaloblastic and non-megaloblastic anemia). When LDH>2076.5 IU/L, there is more probability of having megaloblastic anemia than non-megaloblastic anemia but when LDH>2076.5 and MCV>109.45 with bilirubin> 1.2mg/dl will must more probably not have non-megaloblastic anemia (the specificity was 100%), all three parameters combined together can be used as screening test to distinguish between the 2 groups of macrocytic anemia (megaloblastic and non-megaloblastic) without necessity of bone marrow aspiration in patients of non- regenerative macrocytic anemia. Present study had also shown that there were a positive relationship between serum LDH and MCV (r=+0.613).

Amyotrophic Lateral Sclerosis, FUS and Protein Synthesis Defects.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that mainly affects the motor system. It is a very heterogeneous disorder, so far more than 40 genes have been described as responsible for ALS. The cause of motor neuron degeneration is not yet fully understood, but there is consensus in the literature that it is the result of a complex interplay of several pathogenic processes, which include alterations in nucleocytoplasmic transport, defects in transcription and splicing, altered formation and/or disassembly of stress granules and impaired proteostasis. These defects result in protein aggregation, impaired DNA repair, mitochondrial dysfunction and oxidative stress, neuroinflammation, impaired axonal transport, impaired vesicular transport, excitotoxicity, as well as impaired calcium influx. We argue here that all the above functions ultimately lead to defects in protein synthesis. Fused in Sarcoma (FUS) is one of the genes associated with ALS. It causes ALS type 6 when mutated and is found mislocalized to the cytoplasm in the motor neurons of sporadic ALS patients (without FUS mutations). In addition, FUS plays a role in all cellular functions that are impaired in degenerating motor neurons. Moreover, ALS patients with FUS mutations present the first symptoms significantly earlier than in other forms of the disease. Therefore, the aim of this review is to further discuss ALS6, detail the cellular functions of FUS, and suggest that the localization of FUS, as well as protein synthesis rates, could be hallmarks of the ALS phenotype and thus good therapeutic targets.

Cholestasis associated to inborn errors in bile acid synthesis

Several metabolic pathways are involved in the biotransformation of C27 neutral cholesterol to C24 primary bile acids (BAs), mainly cholic acid (CA) and chenodeoxycholic acid (CDCA), which are then conjugated with glycine or taurine. This process can start with the modification of the steroid ring or the shortening of the side chain and involves enzymes present in different subcellular compartments. Inborn errors affecting the biogenesis of organelles, such as peroxisomes, or the expression or function of specific enzymes of these convergent routes result in: i) the lack of mature C24-BAs, with the subsequent impairment in digestion and absorption of dietary fat and liposoluble vitamins, such as vitamin K, which may account for a deficient hepatic synthesis of several coagulation factors; ii) the accumulation of intermediate metabolites, which may affect hepatocyte physiology, causing cholestasis as a commonly shared alteration besides other deleterious hepatic events; and iii) extrahepatic clinical manifestations due to accumulation of toxic metabolites in other territories, such as the nervous system, causing neurological disorders. In general, diseases whose primary alteration is a genetic defect in BA synthesis are diagnosed in children or young individuals with a very low incidence. The symptomatology can markedly vary among individuals, ranging from mild to severe conditions. Oral therapy, based on the enrichment of the BA pool with natural C24-BAs, such as CA, CDCA, glyco-CA, or ursodeoxycholic acid (UDCA), depending on the exact deficiency causing the disease, may be beneficial in preventing life-threatening situations. In contrast, in other cases, a liver transplant is the only option for these patients. This review describes the updated information on the genetic and molecular bases of these diseases and the current approaches to achieve a selective diagnosis and specific treatment.

Vulvovaginal atrophy in the peri- and post-menopause: relevance and impact on quality of life

Vulvovaginal atrophy (VVA) is detected in more than 50% of postmenopausal women, and at 4049 years of age, 15-19% of women have relevant signs. Atrophic changes in the female urogenital system are associated with hypoestrogenism, which results in the defective synthesis of collagen and elastin due to reduced functional activity of fibroblasts. Although the symptoms of genitourinary syndrome of menopause significantly impair the quality of life, women rarely seek medical help for urogenital symptoms, considering them a normal condition for the period of aging. We searched Cochrane Library, PubMed, Science Direct, and ELibrary databases for the keywords vulvovaginal atrophy, genitourinary syndrome of menopause, quality of life, epidemiology, and postmenopausal age for 20122022. The literature review suggests that the prevalence of VVA is extremely high but underestimated due to the infrequent seeking of medical care by female patients with relevant symptoms. The genitourinary syndrome of menopause dramatically impacts patients' quality of life, but not all women eligible for treatment receive it. One of the reasons for refusing hormonal treatment is patients' fear of the systemic effects of hormonal drugs. There is an unmet need for alternative non-hormonal therapies. The objective is to analyze and systematize the scientific data accumulated over the past ten years on the epidemiology of VVA, its impact on patients' quality of life, and the challenges in diagnosing and treating the disease.

Methotrexate-induced acute cardiotoxicity requiring veno-arterial extracorporeal membrane oxygenation support: a case report

BackgroundMethotrexate is an antifolate antimetabolite that inhibits the activity of dihydrofolate reductase by acting as a false substrate, which leads to defects of DNA synthesis, specifically the inhibition of purine and pyrimidine synthesis. Thus, methotrexate is a powerful agent for treating autoimmune diseases and cancer. In general, methotrexate is thought to be cardioprotective and reports of methotrexate-induced cardiomyopathy are rare. We present a case of methotrexate-induced severe cardiotoxicity diagnosed by exclusion of all other potential causes.Case presentationThe patient was a 54-year-old Caucasian man presenting to an outside hospital with a chief complaint of abdominal pain and bloating who reported taking methotrexate up to 20 mg per week for systemic sclerosis. After a transthoracic echocardiogram found a left ventricular ejection fraction of 10% and coronary catheterization demonstrated no significant disease, he was transferred to our hospital for advanced heart failure therapies. His condition deteriorated, and he was eventually placed on veno-arterial extracorporeal membrane oxygenation. Owing to a lack of an identifiable etiology of cardiac failure, toxicology consultation recommended 24 hours of intravenous leucovorin therapy to overcome any residual and potentially cardiotoxic methotrexate still in his system. Over the next 5 days, his cardiac function improved daily, such that on day 5 of extracorporeal membrane oxygenation, he had a left ventricular ejection fraction of 40% and was able to be decannulated. Two days later, his ejection fraction improved to 60% and normal right ventricular function. Initially, his renal function improved while on extracorporeal membrane oxygenation, but over the next week deteriorated such that he required intermittent hemodialysis until hospital discharge.ConclusionsAfter a process of elimination, the most likely cause of this patient’s acute decline and rapid recovery of bi-ventricular function was methotrexate toxicity. Leucovorin may have aided the reversal of methotrexate toxicity.

Mutational analysis of ribosomal proteins in a cohort of pediatric patients with T-cell acute lymphoblastic leukemia reveals Q123R, a novel mutation in RPL10.

T-cell acute lymphoblastic leukemia (T-ALL) is a subtype of ALL involving the malignant expansion of T-cell progenitors. It is driven by a number of different possible genetic lesions, including mutations in genes encoding for ribosomal proteins (RPs). These are structural constituents of ribosomes, ubiquitous effectors of protein synthesis. Albeit the R98S mutation in RPL10, recurring with a higher frequency among RP mutations, has been extensively studied, less is known about the contribution of mutations occurring in other RPs. Alterations affecting translational machinery may not be well tolerated by cells, and there may be a selective pressure that determines the emergence of mutations with a compensatory effect. To explore this hypothesis, we sequenced the exomes of a cohort of 37 pediatric patients affected by T-ALL, and analyzed them to explore the co-occurrence of mutations in genes involved in ribosome biogenesis (including RPs) and translational control, and in known T-ALL driver genes. We found that some of the mutations in these sub-classes of genes tend to cluster together in different patients, indicating that their co-occurrence may confer some kind of advantage to leukemia cells. In addition, our sequencing highlighted the presence of a novel mutation in RPL10, namely the Q123R, which we found associated with a defect in protein synthesis. Our findings indicate that genetic alterations involving ribosome biogenesis and translational control should be carefully considered in the context of precision medicine in T-ALL.

Manipulation of Thymidine Nucleotide Metabolism Controls Human Telomere Length and Promotes Telomere Elongation in Dyskeratosis Congenita Patient Derived Cells

Inherited mutations in telomere maintenance genes are associated with short telomeres and can cause severe diseases including the congenital bone marrow failure syndrome dyskeratosis congenita, liver cirrhosis, and pulmonary fibrosis, collectively referred to as telomere biology disorders (TBDs). Current approaches to treat TBDs rely on bone marrow and organ transplantation, and patients face poor prognoses. New systemic therapies to promote telomere elongation and treat TBDs throughout the body are needed. Here, we performed the first genome-wide CRISPR/Cas9 functional telomere length screen using flow cytometry-FISH (flow-FISH) in human cells to identify novel telomere maintenance pathways that might be manipulated for therapeutic benefit. Validating our approach, we found guide RNAs targeting positive (e.g. TERT) and negative (e.g. POT1 and TRF1) regulators of telomere length enriched in sorted cells with short and long telomeres, respectively. Unbiased pathway analysis of screening hits demonstrated nucleotide metabolism genes to be highly associated with telomere length, consistent with recent genome-wide association studies, and which in follow-up screening we narrowed down to multiple control points specifically along the thymidine (dT) nucleotide metabolism pathway. Targeted genetic disruption using CRISPR/Cas9 revealed that decreasing dT nucleotide salvage by thymidine kinase (TK1) or de novo production by thymidylate synthase (TYMS) reduced telomere length, whereas inactivation of the dNTPase-encoding gene SAMHD1 lengthened telomeres. We next asked whether nucleotide precursor manipulation could alter telomere length dynamics. Remarkably, we found supplementation with dT nucleoside alone drove rapid telomere elongation in human cells (Figure 1). Telomere elongation after dT treatment required conversion to thymidine monophosphate (dTMP) by TK1, was telomerase dependent, and could be achieved at doses that did not inhibit cell cycle progression. In cells with TYMS deletion or after treatment with the TYMS inhibitor 5-fluorouracil, dT supplementation was sufficient to bypass the de novo nucleotide synthesis defect and promoted robust telomere elongation. SAMHD1 overexpression blunted the degree of telomere elongation from dT treatment in a manner requiring its dNTPase activity, suggesting that telomere length control occurs at the level of dTTP in human cells. To assess whether nucleotide manipulation could overcome the genetic causes of telomere insufficiency which drive TBDs, we tested dT on induced pluripotent stem cell (iPSC) lines derived from patients harboring mutations in a spectrum of TBD-associated genes including DKC1, TERC, TERT, TINF2, RTEL1, and PARN. We found dT supplementation or inhibition of SAMHD1 drove robust telomere elongation in patient derived iPSCs spanning genotypes that cause telomere maintenance defects both by telomerase-dependent and telomerase-independent mechanisms. In preliminary experiments using primary human hematopoietic stem and progenitor cells, dT treatment resulted in telomere elongation in vitro, pointing to a potential treatment for TBD-associated bone marrow failure. Collectively, our results demonstrate a critical role of thymidine nucleotide metabolism in regulating human telomere length. Based on our findings, we propose there may be a therapeutic window to modulate telomere length by manipulating dT metabolism in patients with TBDs. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Clinical Burden of Alpha- and Beta-Thalassemia Compared to Matched Controls in the Real-World Setting

Introduction Thalassemia is an inherited anemia caused by diminished globin chain synthesis. More severe forms lead to ineffective erythropoiesis and chronic hemolytic anemia (HA) with subsequent clinical complications. Two types of thalassemia, alpha (α) and beta (β), result from defective synthesis of α- or β-globin, respectively. Limited research has been conducted in the US regarding burden of comorbidities, including both non-transfusion dependent thalassemia (NTDT) and transfusion dependent thalassemia (TDT), especially α-thalassemia. Methods Claims data for patients and controls were selected from the MarketScan® Commercial and Medicare and Multi-State Medicaid claims databases. Patients were those with ≥1 inpatient or ≥2 claims in any setting for α- or β-thalassemia international classification of diseases (ICD)-9/ICD-10 codes from 1/1/2013 to 6/30/2021 (Table 1). Due to limitations in billing claims, some patients with thalassemia trait and minor may have been coded incorrectly by physicians and included in the NTDT group. The index date was defined as the first date of α- or β-thalassemia diagnosis code. Adults (≥18 years) with 12 months of continuous enrollment following index were included. TDT was defined as ≥8 transfusions within 12 months of follow-up, each within 42 days of each other. Controls with no history of thalassemia or other HAs were matched at 5:1 to thalassemia cases on age, sex, payer, and follow-up time. Medicaid patients were also matched on race. Thalassemia-related clinical outcomes, including pulmonary hypertension, cardiovascular disease, cerebrovascular disease, osteoporosis, and other comorbidities were measured during 12 months of follow-up and compared to matched controls. Chi-square (categorical variables) and t-tests (continuous variables) were used for outcome comparisons with a significance level of 0.05. Results In the commercial and Medicare population, a total of 4,183 patients with thalassemia and 20,915 matched controls were analyzed. Of patients with thalassemia, 1,675 (40.0%) had α-thalassemia and 2,508 (60.0%) had β-thalassemia. In the 12 months following index, 2 (0.1%) α-thalassemia and 84 (3.3%) β-thalassemia had TDT; 1,673 (99.9%) α-thalassemia and 2,424 (96.7%) β-thalassemia had NTDT (Table 1). Sensitivity analysis without the 42-day requirement between transfusions had a minimal impact on TDT numbers. The average age for NTDT was 46.3 (SD 14.8) years and 29.4% were male. Compared to matched controls, α-NTDT and β-NTDT were more likely to have cardiovascular disease (α-NTDT: 7.2% vs. 4.7%; β-NTDT: 7.3% vs. 4.9%), cerebrovascular disease (α-NTDT: 3.8% vs. 1.9%; β-NTDT: 3.5% vs. 2.3%), pulmonary hypertension (α-NTDT: 1.1% vs. 0.3%; β-NTDT: 1.2% vs. 0.3%), jaundice (α-NTDT: 1.0% vs. 0.2%%; β-NTDT: 1.7% vs. 0.1%) and liver disease (α-NTDT: 1.2% vs 0.4%, β-NTDT: 2.2% vs. 0.5%) (all p<0.001) (Table 2). Osteoporosis (α-NTDT: 3.9% vs. 2.6% and β-NTDT: 4.5% vs. 2.5%; both p<0.005) and hypogonadism (α-NTDT: 1.8% vs. 1.0%, p=0.005; β-NTDT: 1.6% vs. 1.1%, p=0.045) were also more frequent among NTDT than matched controls. α-NTDT (1.7 [SD 1.5] vs. 1.1 [SD 1.2]) and β-NTDT (1.8 [SD 1.5] vs. 1.1 [SD 1.3]) had a higher mean number of comorbidities than their respective controls (both p<0.001; Table 1). β-TDT also had higher comorbidities compared to matched controls; there were too few patients with α-TDT to report. The Medicaid analysis of thalassemia compared to controls showed similar results to the Commercial/Medicare analysis, with a larger difference in the number of comorbidities observed (α-NTDT (2.3 [SD 1.8] vs. 1.1 [SD 1.4]) and β-NTDT (2.7[SD 1.8] vs. 1.3 [SD 1.5]; both p<0.001). Conclusions Serious comorbidities and unmet needs persist for patients with thalassemia, even in thalassemia types that have historically been considered less severe such as NTDT. Both α-NTDT and β-NTDT had significantly higher clinical burden than matched controls including endocrinopathies, cardiovascular disease, liver disease and pulmonary hypertension - conditions associated with considerable morbidity and mortality. Some individuals with thalassemia minor or trait may have been included, suggesting that NTDT estimates in this study provide a lower boundary for the impact of NTDT. Additional therapies are needed to address the underlying cause of the disease, and for prevention of these serious complications. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Severe hypercholesterolemia in a patient with very low albumin and normal renal function

A 20-year-old male presented with severe elevation in low-density lipoprotein cholesterol (LDL-C). Initial genetic testing for familial hypercholesterolemia was negative. Patient also had low albumin, and further genetic testing showed homozygous variants in the ALB gene, suggesting congenital analbuminemia (CAA) causing severe hyperlipidemia. CAA is an autosomal recessive disorder with incidence of about 1:1,000,000. The gene for albumin is a single autosomal gene, and pathological variants that affect splicing lead to premature stop, nonsense variants, and deletions that result in a defect in albumin synthesis with CAA. CAA can be fatal in the prenatal period and cause infections in early childhood. CAA is tolerated better in adulthood because of compensatory increase in other plasma proteins. Plasma lipoproteins also increase, and CAA can cause gross hyperlipidemia with severe elevations in LDL-C and hypercholesterolemia. Genetic examination of ALB is mandatory to establish the diagnosis. Early diagnosis may be important to initiate lipid-lowering treatments to avoid premature coronary artery disease.

Consideration of Acute Porphyria in an Emergency Department Patient: A Case Report and Discussion of Common Pitfalls.

Porphyria refers to a group of disorders associated with defects in heme synthesis. They can be associated with severely debilitating features, including abdominal pain, psychiatric symptoms, neurological defects, and cardiovascular irregularities. Although these diseases are rare, patients with attacks often do present to the emergency department (ED) where consideration of porphyria is generally not included in the differential. Here, we examine a case of a 16-year-old male who presented to our ED for evaluation of recurring abdominal pain and auditory hallucinations in which porphyria was considered by the emergency physician. Not considering acute porphyria in patients with recurring neurovisceral symptoms in the ED can lead to missed opportunities for diagnosing such pathologies.

OR04-2 WNT2B Deficiency Results in Hyperreninemic Hypoaldosteronism in Humans and Mice

Abstract Proper development and zonation of the adrenal cortex is intimately connected with its lifelong capacity to produce steroid hormones. Both adrenocortical development and homeostasis are mediated in part by paracrine WNT/β-catenin signaling, an essential pathway for zonal maintenance and aldosterone production. Patients harboring homozygous or compound heterozygous loss-of-function (LOF) mutations in the WNT ligand WNT2B present with congenital diarrhea and require parenteral nutrition. Despite evidence for euvolemia, WNT2B-null patients exhibit markedly elevated plasma renin levels with no corresponding increase in aldosterone, suggesting a primary adrenal defect in aldosterone synthesis. To test this hypothesis, we generated both global and conditional Wnt2b knockout mouse models. In the mouse adrenal, Wnt2b is expressed exclusively in the capsule, the outer compartment of mesenchymal cells that overlay and signal to the subcapsular zona glomerulosa (zG), the adrenocortical zone that harbors aldosterone-producing cells and critical long-term progenitor cells. Global loss of Wnt2b from early mouse development results in a near-complete absence of the histological zG. Moreover, Wnt2b-null mice exhibit significantly increased plasma renin but normal aldosterone levels compared to wild-type controls. These data suggest that WNT2B-null patients indeed have an adrenocortical phenotype caused by apparent zG hypofunction. To further define the mechanism(s) by which Wnt2b LOF leads to zG hypofunction, we temporally deleted Wnt2b in the adrenal capsule of adult mice. Wnt2b conditional knockout (cKO) adrenals exhibit a zG-restricted decrease in Wnt/β-catenin signaling as determined by decreased β-catenin activity and target gene expression. Moreover, Wnt2b cKO mice demonstrated a disorganized zG and disrupted adrenocortical zonation. To determine the contribution of WNT2B to aldosterone production, we administered a sodium-deficient diet to control and Wnt2b cKO mice to activate the renin-angiotensin-aldosterone system. Indeed, while control mice exhibited the expected increase in both plasma renin and aldosterone, Wnt2b cKO mice showed marked elevation of renin despite normal aldosterone compared to controls, consistent with hyperreninemic hypoaldosteronism. Together, our work supports a WNT2B-dependent mechanism for adrenal zG development and maintenance in mice and humans and provides relevant models to study the consequences of WNT2B deficiency within the zG. Presentation: Saturday, June 11, 2022 11:45 a.m. - 12:00 p.m.

RF13 | PMON48 A novel missense variant in the gene encoding Fatty Acid Synthase (FASN) associated with a unique multi-system disorder including hypopituitarism and hypoparathyroidism

Abstract A male patient presented with a unique complex phenotype including panhypopituitarism, short stature with failure to respond to GH [IGF-1 generation test: no response to 2.8 mg/m2/day GH], sensorineural deafness, hypoparathyroidism, retinal dystrophy, and intellectual disability. He was 127cm tall at the age of 21 and was completely prepubertal (LH 0.8 U/L, FSH 2.6 U/L, Testosterone &amp;lt;0.69 nmol/L) with a bone age of 12 years. A trial of recombinant IGF-1 failed to improve growth. He died at the age of 26 years following a collapse of unknown etiology. Exome sequencing and subsequent variant calling on this patient revealed a novel heterozygous de novo missense variant (c.6395C&amp;gt;T, p.A2132V) at a highly conserved residue in FASN encoding Fatty Acid Synthase. The variant was not present in any control database, including the GnomAD browser. Human embryonic brain expression analysis using in situ hybridisation, revealed FASN mRNA transcript staining in the diencephalon and hypothalamus at Carnegie stages (CS) 16, 19, 20 and 23, and in Rathke's pouch (primordium of the anterior pituitary) at CS16 only. Fatty acid synthase (FASN), a crucial multienzyme with seven different catalytic activities, converts acetyl-CoA and malonyl-CoA into long-chain saturated fatty acids such as palmitate, in the presence of NADPH. Murine null mutant Fasn-/- embryos die before implantation and Fasn+/- embryos at various stages in the early postnatal period. Fasn is expressed in multiple tissues including the brain, parathyroids, liver and adrenal. Biochemical investigation of the patient revealed high triglyceride concentrations (3.81-6.49 mmol/L; NR 0.38-2) at all time points during an 18 hour fast. He mobilised free fatty acids but did not generate an increase in 3-hydroxybutyrate, suggesting a defect in fatty acid oxidation or ketone body synthesis. He maintained normoglycaemia with normal hormone responses to fasting, except for an undetectable IGF-1 (&amp;lt;25 ng/ml) and IGFBP-3 (1.17 mg/L). We measured de novo fatty acid synthesis in cultured patient and control fibroblast cells with 13C-Glucose, with and without the C75 fatty acid synthase inhibitor. Cell pellets were collected at three time-points, and 13C-fatty acids derived from 13C-glucose were analysed by mass spectrometry. Preliminary data showed that more C13-glucose was incorporated into de novo synthesised palmitic acid in control cells, suggesting reduced fatty acid synthesis in the patient. Our data suggest that FASN p.A2132V is pathogenic and contributed significantly to the complex patient phenotype, consistent with recent studies suggesting that neural stem/progenitor cells (NSPCs) in the rodent brain are governed by Fasn-dependent de novo lipogenesis for proliferation. Presentation: Sunday, June 12, 2022 12:36 p.m. - 12:41 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

RF21 | PSAT77 ROLE OF THE TRANSCRIPTION FACTOR HHEX IN INNER ADRENAL CORTEX HOMEOSTASIS AND RESPONSE TO PROGESTERONE SIGNALING

Abstract Congenital adrenal hyperplasia (CAH) is a set of defects in cortisol synthesis due to mutations in genes encoding steroidogenic enzymes. Consequently, the loss of glucocorticoid-mediated negative feedback on the HPA axis leads to chronically elevated ACTH (Adrenocorticotropin Hormone) secretion. The sustained ACTH elevation, in turn, stimulates proliferation and hypertrophy of the adrenal cortex and leads to overproduction of androgens. To study the complexity of the ACTH-responsive cell population in the adrenal cortex, we performed single-cell RNA sequencing of the steroidogenic lineage in the adult mouse adrenal. We identified the transcription factor HHEX as a gene with restricted expression in the ACTH-responsive zona fasciculata. Although the role of HHEX in adrenal biology is completely unknown, a meta-analysis identified a germ-line variant of uncertain significance near the gene HHEX associated with increased DHEAS (adrenal-specific androgen) in human serum samples, which led us to hypothesize that HHEX contributes to the unique function of the ACTH-responsive inner cortex. To investigate the mechanisms by which HHEX controls adrenal differentiation and homeostasis, we generated genetically modified mice harboring a deletion of the Hhex gene in the adrenal cortex. Hhex KO mice exhibited progressive adrenomegaly by 15 weeks of age, accompanied by hypertrophy prominent in the inner cortex and disruption of the endothelial organization. Expression of the transcription factor Nr5a1/Sf-1 and steroidogenic enzymes involved in corticosterone production were significantly upregulated at 6 weeks old, prior to adenomegaly, suggesting a precocious increase in cell production of glucocorticoids. For insights into the signaling pathways controlled by HHEX, we analyzed global transcriptional changes during loss of Hhex and found dramatic downregulation of members of the membranous progesterone receptor family (PAQR). PAQR signaling has been implicated in the downregulation of cAMP, a primary mediator of ACTH signaling, and thereby could, in part, drive the increase in steroidogenesis in Hhex KO mice. These findings suggest that the inner cortex contains a progesterone-responsive cell population in which HHEX provides additional fine-tuning of ACTH-driven cAMP signaling by progesterone and derivatives. Since we observed an increase in Hhex expression in a mouse model of CAH, experiments are now ongoing to assess the implication of HHEX and autocrine progesterone signaling in contributing to the hypertrophy and steroidogenic phenotype observed in CAH. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Sunday, June 12, 2022 12:54 p.m. - 12:59 p.m.