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In this paper, a thorough theoretical investigation of high-efficiency class-F power amplifier (PA) is undertaken to drive, considering the second and fourth harmonics of input voltage. The precise analytical expressions of the gate-source voltage, drain current, output power, and efficiency are extracted. Maximum normalized output power and maximum drain efficiency from the initial phase and amplitude of the second and fourth harmonics of input gate-voltage can be achieved. The simulation of class-F PA using a GaN CGH40010F transistor has been done to validate the theoretical analysis. Addition of the fourth harmonic gate voltage along with the second harmonic improves the output power and efficiency of the PA by 0.7 dBm and 4.1%. Based on the simulation with realistic elements, a highly efficient PA operating from 1.8 to 2.2 GHz is implemented. The fabricated PA provides an efficiency of 72–87.6%, PAE of 65–80% and an output power of 39.3–41 dBm.

Background X-linked lymphoproliferative syndrome type 1 (XLP1) is a rare inborn error of immunity with high mortality rates. Neurological manifestations may be the presenting features and are often fatal; however, their characterization is insufficient, hindering optimal clinical management. The aim of this study is to systematically review the neurological characteristics, outcomes, and survival in XLP1 patients and identify parameters associated with improved prognosis. A PRISMA-guided analysis of PubMed, Web of Science, Scopus, and Embase (up to March 2025) identified studies documenting neurological involvement in genetically verified XLP1 patients. We extracted data on clinical features, neuroimaging findings, therapeutic interventions, and survival. Results We identified 42 genetically verified XLP1 patients with neurological involvement. Central nervous system (CNS) involvement comprised hemophagocytic lymphohistiocytosis (HLH) in 38.1%, vasculitis in 28.6%, and lymphoma in 19% of them. The development of brain vasculitis several months after Burkitt’s lymphoma was a specific presentation. The median age of neurological onset was 5 years. The predominant presenting symptoms were seizures (47.6%), altered consciousness (35.7%), and headaches (21.4%). Neuroimaging frequently revealed abnormalities in the temporal lobe and basal ganglia, often with hemorrhage and edema. Epstein-Barr virus (EBV) was identified in 54.8% of cases, sometimes limited to brain tissue. CSF analysis frequently showed elevated protein and pleocytosis. SH2D1A mutations were diverse, with Arg55 and Trp64 identified as recurrent hot spots. The overall mortality reached 52.4%, with most deaths occurring within five years of neurological onset. Conventional immunosuppressive and cytotoxic treatments were largely ineffective in changing the disease course. In exploratory analysis, hematopoietic stem cell transplantation (HSCT) did not significantly improve survival in the primary dataset, although sensitivity analysis suggested a possible benefit. Conclusions Neurological involvement in XLP1 exhibits clinical heterogeneity and carries a high mortality rate. Early recognition and timely HSCT may improve survival, demonstrating the importance of vigilant neurological monitoring in affected individuals.

Background Coronavirus disease 2019 (COVID-19) is a disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the seventh coronavirus to be linked to human disease. The SARS-CoV-2 virus may have several pathophysiologic interactions with endocrine systems, resulting in disruptions in glucose metabolism, hypothalamus and pituitary function, adrenal function, and mineral metabolism. An increasing amount of evidence demonstrates both the influence of underlying endocrine abnormalities on the outcome of COVID-19 and the effect of the SARS-CoV-2 virus on endocrine systems. However, a systematic examination of the link to pediatric endocrine diseases has been missing. Data sources The purpose of this review is to discuss the impact of SARS-CoV-2 infection on endocrine systems and to summarize the available knowledge on COVID-19 consequences in children with underlying endocrine abnormalities. For this purpose, a literature search was conducted in EMBASE, and data that were discussed about the effects of COVID-19 on endocrine systems were used in the current study. Results Treatment suggestions were provided for endocrinopathies associated with SARS-CoV-2 infection. Conclusions With the global outbreak of COVID-19, it is critical for pediatric endocrinologists to understand how SARS-CoV-2 interacts with the endocrine system and the therapeutic concerns for children with underlying problems who develop COVID-19. While children and adults share certain risk factors for SARS-CoV-2 infection sequelae, it is becoming obvious that pediatric responses are different and that adult study results cannot be generalized. While pediatric research gives some insight, it also shows the need for more study in this area.

Maple Syrup Urine Disease (MSUD) disease is a defect in the function of the Branched-chain 2-ketoacid dehydrogenase complex (BCKDH). It is caused by pathogenic biallelic variants in BCKDHA, BCKA decarboxylase, or dihydrolipoamide dehydrogenase. The brain is the major organ involved in MSUD. MSUD happens in about 1 in 86,800 to 185,000 live births. According to some diversity in the management of Iranian patients with MSUD, the development of a national guideline is essential. This guideline is provided through a literature search on articles in PubMed, Scopus, Web of Sciences, Cochrane, and Embase databases from 2001 to 2022 accompanied by a consensus of physicians of different centers in Iran who are experts in the diagnosis and management of this disease. This article considers pathogenesis, epidemiology, clinical manifestations, diagnosis, treatment, and monitoring of MSUD patients with limited recourse.

Background Complete complement factor I (CFI) deficiency is an inborn error of immunity (IEI) that results in heightened susceptibility to infections and immune dysregulatory disorders. This systematic review seeks to enhance our understanding of the clinical characteristics, genotype–phenotype correlations, and treatment outcomes in patients with complete CFI deficiency, including three novel cases. We conducted a comprehensive literature review of cases published from 1996 to November 2024, identifying 49 patients with homozygous or compound heterozygous mutations in the CFI gene. Results Among the 49 patients, the mean age at initial presentation was 7.19 (± SD: 9.75) years. Most patients presented with infectious manifestations (n: 37, 75.5%), particularly sepsis (n: 18, 36.7%). The predominant pathogens were encapsulated organisms, particularly Neisseria meningitidis . Immune dysregulatory manifestations involved rheumatologic (n: 14, 28.57%), neurologic (n: 11, 22.4%), and renal (n: 8, 16.3%) disorders. Immunological evaluations showed low or absent levels of C3 and CFI in most patients. Genetic analysis identified 45 distinct mutations; less deleterious mutations, such as missense and splicing variants, were more common in those with immune dysregulation. Notably, three patients treated with eculizumab demonstrated significant clinical improvement. Conclusion Complete CFI deficiency presents a varied clinical spectrum, from asymptomatic to recurrent infections and immune dysregulation. Early diagnosis and targeted therapies, such as eculizumab, may improve patient outcomes. These findings underscore the necessity for further research into the nature of complete CFI deficiency and the development of optimal management strategies.

Background Infantile Sandhoff disease (ISD) is a GM2 gangliosidosis that is classified as a lysosomal storage disorder. The most common symptoms of affected individuals at presentation are neurologic involvement. Here we report clinical course and demographic features in a case series of infantile Sandhoff disease. Enzymatically and some genetically proven cases of ISD were extracted from the Iranian Neurometabolic Registry (INMR) in Children’s Medical Center, Iran, Tehran from December 2010 to December 2016. Result Twenty five cases of infantile SD (13 female, 12 male) were included in this study. The age range of patients was 9–24 months with a mean of 15.8 months. The consanguinity rate of parents affected families was about 80%. The mean age of patients at disease onset was 6.4 months and the mean age at diagnosis was 14 months. Patients were diagnosed with a mean delay of 7.8 months. Eleven of patients died due to aspiration pneumonia and intractable seizure. The most common features at presentation (92%) were developmental delay or regression in speech and cognitive domains. Cherry red spots were detected in 17 patients (68%). Organomegaly was detected only in two patients. Enzyme studies showed marked reductions of both Hexosaminidase A and B in all patients. HEXB gene mutation studies performed in eight patients identified 6 different mutations, which five of them were novel. Conclusion Infantile SD should be considered for each child presented with neurologic symptoms such as developmental delay and regression and cherry red spots in ophthalmic examination. Organomegaly is not a frequent clinical finding in infantile SD. Additionally; there are a genetic heterogenisity among Iranian patients.

Objective Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) is a rare autosomal recessive systemic autoimmune disease caused by mutations in the autoimmune regulator ( AIRE) gene. Incidence of this genetic disorder is estimated at 1/90,000–200,000 worldwide and 1/6500–9000 in genetically isolated populations such as Iran. Here, we investigated AIRE gene mutations in eight independent Iranian non-Jewish families. Methods We sequenced the coding regions of the AIRE gene and documented mutations which were further confirmed in respective parents. Results In total, 11 cases from 8 independent families were recruited. Mucosal candidiasis, Addison’s disease and hypoparathyroidism were the most common clinical manifestations in these patients. One novel homozygous splice acceptor mutation (c.308-1G>C), and one novel heterozygous stop-gain mutation (c.1496delC) combined with a known heterozygous c.232T>C missense mutation were found. Moreover, we observed previously described splice donor (c.1095+2T>A), frameshift (c.967-979del), stop-gain (c.415C>T), and missense (c.62C>T) mutations among the patients. All results were co-segregated in parents. Conclusion Here, we reported two novel mutations in the AIRE gene leading to APECED. Our data could provide insight into the phenotypic and genotypic spectrum of APECED in the non-Jewish Iranian population. These findings, in addition to future functional assays, can elucidate disease-causing mechanisms related to the AIRE gene and assist in genetic counseling and diagnosis.

Background Glycogen storage disease (GSD) is a rare inborn error of the synthesis or degradation of glycogen metabolism. GSD1, the most common type of GSD, is categorized into GSD1a and GSD1b which caused by the deficiency of glucose-6-phosphatase ( G6PC ) and glucose-6-phosphate transporter ( SLC37A4 ), respectively. The high rates of consanguineous marriages in Iran provide a desirable context to facilitate finding the homozygous pathogenic mutations. This study designates to evaluate the clinical and genetic characteristics of patients with GSD1b to assess the possible genotype-phenotype correlation. Results Autozygosity mapping was performed on nineteen GSD suspected families to suggest the causative loci. The mapping was done using two panels of short tandem repeat (STR) markers linked to the corresponding genes. The patients with autozygous haplotype block for the markers flanking the genes were selected for direct sequencing. Six patients showed autozygosity in the candidate markers for SLC37A4. Three causative variants were detected. The recurrent mutation of c.1042_1043delCT (p.Leu348Valfs*53) and a novel missense mutation of c.365G > A (p.G122E) in the homozygous state were identified in the SLC37A4 . In silico analysis was performed to predict the pathogenicity of the variants. A novel whole SLC37A4 gene deletion using long-range PCR and sequencing was confirmed as well. Severe and moderate neutropenia was observed in patients with frameshift and missense variants, respectively. The sibling with the whole gene deletion has shown both severe neutropenia and leukopenia. Conclusions The results showed that the hematological findings may have an appropriate correlation with the genotype findings. However, for a definite genotype-phenotype correlation, specifically for the clinical and biochemical phenotype, further studies with larger sample sizes are needed.

A number of inborn errors of metabolism (IEM) have been shown to result in predominantly immunologic phenotypes, manifesting in part as inborn errors of immunity. These phenotypes are mostly caused by defects that affect the (i) quality or quantity of essential structural building blocks (e.g., nucleic acids, and amino acids), (ii) cellular energy economy (e.g., glucose metabolism), (iii) post-translational protein modification (e.g., glycosylation) or (iv) mitochondrial function. Presenting as multisystemic defects, they also affect innate or adaptive immunity, or both, and display various types of immune dysregulation. Specific and potentially curative therapies are available for some of these diseases, whereas targeted treatments capable of inducing clinical remission are available for others. We will herein review the pathogenesis, diagnosis, and treatment of primary immunodeficiencies (PIDs) due to underlying metabolic disorders.

Pericentric inversion of Chromosome 9 is one of the most common chromosomal abnormalities, which could be associated with various manifestations in some cases. Herein, a patient is presented with ambiguous genitalia that karyotyping revealed pericentric inversion of Chromosome 9 (p12,q13). Pericentric inversion of Chromosome 9 could be considered in the list of differential diagnosis of those with ambiguous genitalia, while chromosomal karyotype and culture could be recommended in children with ambiguous genitalia.