Brain function in classic galactosemia, a galactosemia network (GalNet) members review.

Classic galactosemia (CG, OMIM #230400, ORPHA: 79,239) is a hereditary disorder of galactose metabolism that, despite treatment with galactose restriction, affects brain function in 85% of the patients. Problems with cognitive function, neuropsychological/social emotional difficulties, neurological symptoms, and abnormalities in neuroimaging and electrophysiological assessments are frequently reported in this group of patients, with an enormous individual variability. In this review, we describe the role of impaired galactose metabolism on brain dysfunction based on state of the art knowledge. Several proposed disease mechanisms are discussed, as well as the time of damage and potential treatment options. Furthermore, we combine data from longitudinal, cross-sectional and retrospective studies with the observations of specialist teams treating this disease to depict the brain disease course over time. Based on current data and insights, the majority of patients do not exhibit cognitive decline. A subset of patients, often with early onset cerebral and cerebellar volume loss, can nevertheless experience neurological worsening. While a large number of patients with CG suffer from anxiety and depression, the increased complaints about memory loss, anxiety and depression at an older age are likely multifactorial in origin.

Natural history of three late-diagnosed classic Galactosemia patients.

The authors report the natural history of three patients with late-diagnosed Classic Galactosemia (CG) (at 16, 19 and 28 years). This was due to a combination of factors: absence of neonatal screening, absence of some typical acute neonatal symptoms, and negative galactosemia screening. This report underlines the value of neonatal screening and the importance of further diagnostic testing in case of late-onset manifestations.

Sulphur Amino Acids: How Important is it to Set Reference Ranges for Each Population?

INTRODUCTION: Metabolism of sulfur amino acids requires an optimal interplay between nutritional demand, enzymes, transporters, and adequate dietary intake of B vitamins. Insufficient intake and excess are detrimental, and concentrations depend on health status. However, plasma aminothiol concentrations, previously reported in healthy subjects using highly sensitive methods, vary considerably, and age- and gender differences were observed. Therefore, defining age- and gender-specific ranges for each population is crucial to evaluate the meaning of plasma thiol redox state in health and disease. METHODS: A healthy Portuguese pediatric population (n=90), aged 9- (n=38) and 17-year-old (n=52), was evaluated. Plasma aminothiols, total homocysteine (tHcy), cysteine (tCys), glutathione (tGSH) and γ-glutamylcysteine (tγ-Glu-Cys), were analysed as SBD-F derivatives by HPLC with fluorescence detection. RESULTS/CASE REPORT: Mean plasma concentrations (SD) for the 9- and the 17-year-old groups, were as following: tHcy = 4.58 (0.98); 8.13 (3.27) µM, p <0.001; tCys = 207.34 (32.07); 198.59 (21.24) µM, p = 0.274; tGSH = 4.54 (1.08); 5.20 (1.84) µM, p = 0.123 and tγ-Glu-Cys = 1.47 (0.30); 1.06 (0.28) µM, p < 0.001, respectively. No statistically significant differences were found between males and females in the 9-year-old group. However, in the 17-year-old group, significant differences between genders were observed for tHcys (p < 0.001) and tγ-Glu-Cys (p = 0.039), with males presenting the highest concentrations. When correlating the four thiols' plasma concentrations, only the precursors of glutathione, tγ-Glu-Cys and tCys, were positively correlated (r = 0.450, p < 0.001). CONCLUSION: Our results showed significant differences in tHcy and tγ-Glu-Cys levels across both age groups, which increased and decreased with age, respectively. It is interesting to highlight that in the 17-year-old group, tHcy and tγ-Glu-Cys levels were higher in males than in females. These observations showed that age and gender influence plasma levels of thiols, which may impact cellular oxidative status. In conclusion, setting age and gender distinct ranges for each specific population is of utmost importance for understanding disease mechanisms and the effectiveness of therapeutic interventions.

Evaluation of Mitochondrial Function on Pyruvate Dehydrogenase Complex Deficient Patient-derived Cell Lines.

INTRODUCTION: Pyruvate Dehydrogenase Complex (PDC) is a pivotal gatekeeper between cytosolic glycolysis and mitochondrial oxidative phosphorylation, playing important role in aerobic energy metabolism. Most PDC deficiency, cases being caused by mutations in PDHA1 encoding the α subunit of the rate-limiting E1 enzyme, which is characterized by abnormal phenotypes caused by energy deprivation at peripheral/central nervous systems and muscular tissues. This study aims to evaluate the potential therapeutic effect of arginine and thiamine in ameliorating mitochondrial function in patient-derived cultured cells. MATERIALS AND METHODS: PDC-deficient cell lines, carrying three different PDHA1 variants, were cultured in the absence and presence of arginine and/or thiamine at therapeutical levels, 4 mM and 100 µM, respectively. Mitochondrial bioenergetics profile was evaluated using the Seahorse extracellular flux analyzer. RESULTS: In physiological conditions, control cells presented standard values for all parameters evaluating the mitochondrial function, no differences being observed after supplementation of culture medium with therapeutic levels of arginine and/or thiamine. However, PDC-PDHA1 deficient cell lines consumed less oxygen than the control cells, but arginine and thiamine supplementation increased the basal respiration for values similar or higher than the control cell line. Moreover, arginine and thiamine treatment highlighted an inefficient oxidative phosphorylation carried out by PDC-deficient cell lines. Finally, this treatment showed an increased oxygen consumption by enzymes other than those in the respiratory chain, thus proving the dependence of these mutant cell lines on cytosolic sources for ATP production, namely glycolysis. CONCLUSIONS: This study showed that arginine and thiamine, at therapeutical levels, increase the basal oxygen consumption rate of PDC-deficient cell lines, as well as their ATP-linked respiration. This parameter measures the capacity of the cell to meet its energetic demands and, therefore, its increase reveals a higher electron flow through the respiratory chain, which is coupled to elevated oxidative phosphorylation, thus indicating an overall increased robustness in mitochondrial- related bioenergetics.

Clinical Trials on Advanced Therapy Investigational Medicinal Products in Spain (2004-2022): Experience and Challenges for the Future.

Clinical investigation is the basis for establishing how useful advanced therapy investigational medicinal products (ATiMP) are for the treatment of serious diseases.In Spain, clinical trials (CT) on ATiMP need to follow the general European legislation on CT with medicinal products plus some specific legislation and guidance depending on the type of ATiMP.This chapter describes the characteristics of CT on ATiMP authorized in Spain in the period 2004-2022 and the legislation applicable along this period. There are clear differences in the clinical trials conducted by non commercial and commercial sponsors: the first have been more involved in CT on somatic cell therapy medicinal products (sCTMP) and tissue-engineered products (TEP), while the second drive more the CT on gene therapy medicinal products (GTMP) in the last years. Difficulties of budget and resources especially by non-commercial sponsors to meet the regulatory requirements are highlighted. The importance of complying with transparency rules with respect to CT on ATiMP is also discussed.

An efficient method for simultaneous species, individual, and sex identification via in-solution single nucleotide polymorphism capture from low-quality scat samples.

Understanding predator population dynamics is important for conservation management because of the critical roles predators play within ecosystems. Noninvasive genetic sampling methods are useful for the study of predators like canids that can be difficult to capture or directly observe. Here, we introduce the FAECES* method (Fast and Accurate Enrichment of Canid Excrement for Species* and other analyses) which expands the toolbox for canid researchers and conservationists by using in-solution hybridization sequence capture to produce single nucleotide polymorphism (SNP) genotypes for multiple canid species from scat-derived DNA using a single enrichment. We designed a set of hybridization probes to genotype both coyotes (Canis latrans) and kit foxes (Vulpes macrotis) at hundreds of polymorphic SNP loci and we tested the probes on both tissues and field-collected scat samples. We enriched and genotyped by sequencing 52 coyote and 70 kit fox scats collected in and around a conservation easement in the Nevada Mojave Desert. We demonstrate that the FAECES* method produces genotypes capable of differentiating coyotes and kit foxes, identifying individuals and their sex, and estimating genetic diversity and effective population sizes, even using highly degraded, low-quantity DNA extracted from scat. We found that the study area harbours a large and diverse population of kit foxes and a relatively smaller population of coyotes. By replicating our methods in the future, conservationists can assess the impacts of management decisions on canid populations. The method can also be adapted and applied more broadly to enrich and sequence multiple loci from any species of interest using scat or other noninvasive genetic samples.

IVEN: A quantitative tool to describe 3D cell position and neighbourhood reveals architectural changes in FGF4-treated preimplantation embryos.

Architectural changes at the cellular and organism level are integral and necessary to successful development and growth. During mammalian preimplantation development, cells reduce in size and the architecture of the embryo changes significantly. Such changes must be coordinated correctly to ensure continued development of the embryo and, ultimately, a successful pregnancy. However, the nature of such transformations is poorly defined during mammalian preimplantation development. In order to quantitatively describe changes in cell environment and organism architecture, we designed Internal Versus External Neighbourhood (IVEN). IVEN is a user-interactive, open-source pipeline that classifies cells into different populations based on their position and quantifies the number of neighbours of every cell within a dataset in a 3D environment. Through IVEN-driven analyses, we show how transformations in cell environment, defined here as changes in cell neighbourhood, are related to changes in embryo geometry and major developmental events during preimplantation mammalian development. Moreover, we demonstrate that modulation of the FGF pathway alters spatial relations of inner cells and neighbourhood distributions, leading to overall changes in embryo architecture. In conjunction with IVEN-driven analyses, we uncover differences in the dynamic of cell size changes over the preimplantation period and determine that cells within the mammalian embryo initiate growth phase only at the time of implantation.

Structural and functional impact of clinically relevant E1α variants causing pyruvate dehydrogenase complex deficiency.

Pyruvate dehydrogenase complex (PDC) catalyzes the oxidative decarboxylation of pyruvate to acetyl-coenzyme A, hinging glycolysis and the tricarboxylic acid cycle. PDC deficiency, an inborn error of metabolism, has a broad phenotypic spectrum. Symptoms range from fatal lactic acidosis or progressive neuromuscular impairment in the neonatal period, to chronic neurodegeneration. Most disease-causing mutations in PDC deficiency affect the PDHA1 gene, encoding the α subunit of the PDC-E1 component. Detailed biophysical analysis of pathogenic protein variants is a challenging approach to support the design of therapies based on improving and correcting protein structure and function. Herein, we report the characterization of clinically relevant PDC-E1α variants identified in Portuguese PDC deficient patients. These variants bear amino acid substitutions in different structural regions of PDC-E1α. The structural and functional analyses of recombinant heterotetrameric (αα'ßß') PDC-E1 variants, combined with molecular dynamics (MD) simulations, show a limited impact of the amino acid changes on the conformational stability, apart from the increased propensity for aggregation of the p.R253G variant as compared to wild-type PDC-E1. However, all variants presented a functional impairment in terms of lower residual PDC-E1 enzymatic activity and ≈3-100 × lower affinity for the thiamine pyrophosphate (TPP) cofactor, in comparison with wild-type PDC-E1. MD simulations neatly showed generally decreased stability (increased flexibility) of all variants with respect to the WT heterotetramer, particularly in the TPP binding region. These results are discussed in light of disease severity of the patients bearing such mutations and highlight the difficulty of developing chaperone-based therapies for PDC deficiency.

Galactokinase deficiency: lessons from the GalNet registry.

PURPOSE: Galactokinase (GALK1) deficiency is a rare hereditary galactose metabolism disorder. Beyond cataract, the phenotypic spectrum is questionable. Data from affected patients included in the Galactosemias Network registry were collected to better characterize the phenotype. METHODS: Observational study collecting medical data of 53 not previously reported GALK1 deficient patients from 17 centers in 11 countries from December 2014 to April 2020. RESULTS: Neonatal or childhood cataract was reported in 15 and 4 patients respectively. The occurrence of neonatal hypoglycemia and infection were comparable with the general population, whereas bleeding diathesis (8.1% versus 2.17-5.9%) and encephalopathy (3.9% versus 0.3%) were reported more often. Elevated transaminases were seen in 25.5%. Cognitive delay was reported in 5 patients. Urinary galactitol was elevated in all patients at diagnosis; five showed unexpected Gal-1-P increase. Most patients showed enzyme activities ≤1%. Eleven different genotypes were described, including six unpublished variants. The majority was homozygous for NM_000154.1:c.82C>A (p.Pro28Thr). Thirty-five patients were diagnosed following newborn screening, which was clearly beneficial. CONCLUSION: The phenotype of GALK1 deficiency may include neonatal elevation of transaminases, bleeding diathesis, and encephalopathy in addition to cataract. Potential complications beyond the neonatal period are not systematically surveyed and a better delineation is needed.

Pyruvate dehydrogenase complex deficiency: updating the clinical, metabolic and mutational landscapes in a cohort of Portuguese patients.

BACKGROUND: The pyruvate dehydrogenase complex (PDC) catalyzes the irreversible decarboxylation of pyruvate into acetyl-CoA. PDC deficiency can be caused by alterations in any of the genes encoding its several subunits. The resulting phenotype, though very heterogeneous, mainly affects the central nervous system. The aim of this study is to describe and discuss the clinical, biochemical and genotypic information from thirteen PDC deficient patients, thus seeking to establish possible genotype-phenotype correlations. RESULTS: The mutational spectrum showed that seven patients carry mutations in the PDHA1 gene encoding the E1α subunit, five patients carry mutations in the PDHX gene encoding the E3 binding protein, and the remaining patient carries mutations in the DLD gene encoding the E3 subunit. These data corroborate earlier reports describing PDHA1 mutations as the predominant cause of PDC deficiency but also reveal a notable prevalence of PDHX mutations among Portuguese patients, most of them carrying what seems to be a private mutation (p.R284X). The biochemical analyses revealed high lactate and pyruvate plasma levels whereas the lactate/pyruvate ratio was below 16; enzymatic activities, when compared to control values, indicated to be independent from the genotype and ranged from 8.5% to 30%, the latter being considered a cut-off value for primary PDC deficiency. Concerning the clinical features, all patients displayed psychomotor retardation/developmental delay, the severity of which seems to correlate with the type and localization of the mutation carried by the patient. The therapeutic options essentially include the administration of a ketogenic diet and supplementation with thiamine, although arginine aspartate intake revealed to be beneficial in some patients. Moreover, in silico analysis of the missense mutations present in this PDC deficient population allowed to envisage the molecular mechanism underlying these pathogenic variants. CONCLUSION: The identification of the disease-causing mutations, together with the functional and structural characterization of the mutant protein variants, allow to obtain an insight on the severity of the clinical phenotype and the selection of the most appropriate therapy.

Suppressing Aneuploidy-Associated Phenotypes Improves the Fitness of Trisomy 21 Cells.

An abnormal number of chromosomes, or aneuploidy, accounts for most spontaneous abortions, causes developmental defects, and is associated with aging and cancer. The molecular mechanisms by which aneuploidy disrupts cellular function remain largely unknown. Here, we show that aneuploidy disrupts the morphology of the nucleus. Mutations that increase the levels of long-chain bases suppress nuclear abnormalities of aneuploid yeast independent of karyotype identity. Quantitative lipidomics indicates that long-chain bases are integral components of the nuclear membrane in yeast. Cells isolated from patients with Down syndrome also show that abnormal nuclear morphologies and increases in long-chain bases not only suppress these abnormalities but also improve their fitness. We obtained similar results with cells isolated from patients with Patau or Edward syndrome, indicating that increases in long-chain bases improve the fitness of aneuploid cells in yeast and humans. Targeting lipid biosynthesis pathways represents an important strategy to suppress nuclear abnormalities in aneuploidy-associated diseases.

Darier disease: first molecular study of a Portuguese family.

BACKGROUND: Darier disease (DD) is a rare autosomal dominant condition characterized by skin lesions. Additionally, a wide range of neuropsychiatric symptoms is frequently reported in DD patients. This genodermatosis relies on mutations in the ATPase sarcoplasmic/endoplasmic reticulum Ca2+ transporting 2 (ATP2A2) gene, which encodes an ATPase responsible for pumping Ca2+ from the cytosol to the lumen of the ER. OBJECTIVE: Herein we studied the molecular aspect of a two-generation Portuguese family with DD history with clinical variability. METHODS: All exons and intron-exon borders of genomic ATP2A2, as well as coding ATP2A2, were sequenced. Relative levels of SERCA2 mRNA and protein were quantified by qPCR and western blotting, respectively. RESULTS: The c.1287+1G > T variant was identified in all affected individuals, whereas the unaffected individual was shown to carry the wild-type ATP2A2 sequence in both alleles. This variant leads to the skipping of full exon 10, which consequently generates a frameshift originating a premature STOP codon in exon 11 (p.V395 = fs*19). Although the mutant mRNA seems to partially escape degradation, results suggest synthesis inhibition or immediate degradation of the mutant protein. Neuropsychiatric and other occurrences affecting certain patients are also reported. CONCLUSION: This is the first study of DD in Portugal, the variant identified, previously described in a single Japanese patient, may be considered a pathogenic mutation, and haploinsufficiency the mechanism underlying DD pathology in these patients. This study also highlights the co-occurrence of neuropsychiatric features in DD.

[The medical major of health management in Universidad Nacional Mayor de San Marcos: 30 years training managers for the health sector]. / La especialidad medica de gestión en salud en la Universidad Nacional Mayor de San Marcos: 30 años formando gestores para el sector salud.

A historical account of the 30 years of the medical major of Health Management at Universidad Nacional Mayor de San Marcos is presented. The major was created in 1988 as Comprehensive General Medicine in response to the shortage of management specialists. The name of the major remained until 1994, when it changed to Integral Medicine and Health Management to emphasize its managerial orientation. In 2002, the curricular plan was modified considering the importance of having an exclusive medical specialization in management for the health sector. The specialty is a pioneer in a gradual education in three levels: micro-management, meso-management, and macro-management. The new curricular plan allowed residents the possibility to access better rotations at public and private institutions. Since 2007, the major is labeled Health Management, and its specialists maintain their solid training that enables them to perform in the decision-making, management, administration, and operation processes of the health systems. The vision of the creators of this major is current to this day; Health Management specialists work in the different institutions of the health system, contributing their knowledge and skills, and generating an impact on the health of the Peruvian population.

Se presenta un recuento histórico de los 30 años de la especialidad médica de Gestión en Salud en la Universidad Nacional Mayor de San Marcos. La especialidad fue creada en 1988 como Medicina General Integral en respuesta a la escasez de médicos especialistas en gestión. El nombre de la especialidad se mantuvo hasta 1994, cuando cambia a Medicina Integral y Gestión en Salud para enfatizar su orientación gerencial. En 2002, se modifica el plan curricular considerando la importancia de tener una especialización médica exclusiva de gestión para el sector salud. La especialidad es pionera en una formación gradual en tres niveles: microgestión, mesogestión y macrogestión. El nuevo plan curricular permitió a los residentes la posibilidad de mejores rotaciones en instituciones públicas y privadas. A partir del 2007, la especialidad es denominada Gestión en Salud, cuyos médicos especialistas mantienen su sólida formación para desempeñarse en los procesos de decisión, conducción, dirección y operatividad de los sistemas de salud. La visión de los creadores de la especialidad se encuentra vigente, los especialistas de Gestión en Salud se desempeñan en las diferentes instituciones del sistema de salud, aportando sus conocimientos y habilidades, y generando un impacto en la salud de la población peruana.

Homocysteine Metabolism in Children and Adolescents: Influence of Age on Plasma Biomarkers and Correspondent Genotype Interactions.

BACKGROUND: Imbalance of homocysteine (Hcy) metabolism links with several pathologies; nevertheless, it is poorly characterized in pediatric populations. This study investigated the impact of age on plasma concentrations of Hcy and relevant biomarkers along with correspondent genotype interactions. METHODS: A healthy pediatric cohort aged 9 (n = 195) and 17 (n = 128) years old (yo) was studied. Immunoassays and GC-MS-SIM-mode quantified plasma levels of Hcy and biomarkers. PCR-RFLP or quantitative-PCR assays assessed common variations in related genes. RESULTS: Age impacted on levels of Hcy and metabolic markers: older children presented with the lowest folates and total-cobalamin (tCbl), while with the highest Hcy concentrations, whereas methylmalonic acid (MMA) and holotranscobalamin (Holo-TC) levels remained similar in 9-yo and 17-yo children. The relationships between B-vitamins and metabolic markers were also dependent on age. Only in the older children, MMA correlated with tCbl and Holo-TC, and MMA levels were markedly higher in the 17-yo subjects presenting with the lowest quartiles of Holo-TC concentrations. Lastly, age also impacted on the correlations between genotype and biomarkers. In the 17-yo group, however not in the 9-yo children, tHcy differed between MTHFR 677 genotypes, with subjects who had the MTHFR 677TT genotype displaying the highest tHcy concentrations. CONCLUSIONS: Age impacts on the Hcy metabolism dynamics in a pediatric population.

La especialidad médica de gestión en salud en la Universidad Nacional Mayor de San Marcos: 30 años formando gestores para el sector salud / The medical major of health management in Universidad Nacional Mayor de San Marcos: 30 years training managers for the health sector

Se presenta un recuento histórico de los 30 años de la especialidad médica de Gestión en Salud en la Universidad Nacional Mayor de San Marcos. La especialidad fue creada en 1988 como Medicina General Integral en respuesta a la escasez de médicos especialistas en gestión. El nombre de la especialidad se mantuvo hasta 1994, cuando cambia a Medicina Integral y Gestión en Salud para enfatizar su orientación gerencial. En 2002, se modifica el plan curricular considerando la importancia de tener una especialización médica exclusiva de gestión para el sector salud. La especialidad es pionera en una formación gradual en tres niveles: microgestión, mesogestión y macrogestión. El nuevo plan curricular permitió a los residentes la posibilidad de mejores rotaciones en instituciones públicas y privadas. A partir del 2007, la especialidad es denominada Gestión en Salud, cuyos médicos especialistas mantienen su sólida formación para desempeñarse en los procesos de decisión, conducción, dirección y operatividad de los sistemas de salud. La visión de los creadores de la especialidad se encuentra vigente, los especialistas de Gestión en Salud se desempeñan en las diferentes instituciones del sistema de salud, aportando sus conocimientos y habilidades, y generando un impacto en la salud de la población peruana.

A historical account of the 30 years of the medical major of Health Management at Universidad Nacional Mayor de San Marcos is presented. The major was created in 1988 as Comprehensive General Medicine in response to the shortage of management specialists. The name of the major remained until 1994, when it changed to Integral Medicine and Health Management to emphasize its managerial orientation. In 2002, the curricular plan was modified considering the importance of having an exclusive medical specialization in management for the health sector. The specialty is a pioneer in a gradual education in three levels: micro-management, meso-management, and macro-management. The new curricular plan allowed residents the possibility to access better rotations at public and private institutions. Since 2007, the major is labeled Health Management, and its specialists maintain their solid training that enables them to perform in the decision-making, management, administration, and operation processes of the health systems. The vision of the creators of this major is current to this day; Health Management specialists work in the different institutions of the health system, contributing their knowledge and skills, and generating an impact on the health of the Peruvian population.

Modulation of Alzheimer's amyloid ß peptide oligomerization and toxicity by extracellular Hsp70.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder leading to dementia caused by advanced neuronal dysfunction and death. The most significant symptoms of AD are observed at late stages of the disease when interventions are most likely too late to ameliorate the condition. Currently, the predominant theory for AD is the "amyloid hypothesis," which states that abnormally increased levels of amyloid ß (Aß) peptides result in the production of a variety of aggregates that are neurotoxic. The specific mechanisms for Aß peptide-induced cytotoxicity have not yet been completely elucidated. However, since the majority of Aß is released into the extracellular milieu, it is reasonable to assume that toxicity begins outside the cells and makes its way inside where it disrupts the basic cellular process resulting in cell death. There is increasing evidence that hsp, particularly Hsp70, are exported into the extracellular milieu by an active export mechanism independent of cell death. Therefore, both Aß peptides and Hsp70 may coexist in a common environment during pathological conditions. We observed that Hsp70 affected the Aß assembling process in vitro preventing oligomer formation. Moreover, the presence of Hsp70 reduced the Aß peptide-induced toxicity of cultured neurons (N2A cells). These results suggest a potential mechanism for the reduction of the detrimental effects of Aß peptides in AD.

Molecular basis and clinical presentation of classic galactosemia in a Croatian population.

BACKGROUND: Classic galactosemia is an autosomal recessive disorder of galactose metabolism caused by severely decreased activity of galactose-1-phosphate uridylyltransferase (GALT) due to pathogenic mutations in the GALT gene. To date more than 330 mutations have been described, with p.Q188R and p.K285N being the most common in Caucasian populations. Although acute manifestations can be fully avoided by a galactose-restricted diet, chronic complications, such as neurological ones, cannot be prevented in a significant number of patients despite compliance with the dietary treatment. METHODS: A cohort of 16 galactosemic Croatian patients, including one pair of siblings, was studied. Molecular characterization was performed by direct sequence analysis of the GALT gene. RESULTS: Sixteen patients were analyzed and only four different mutations were detected. As expected, p.Q188R and p.K285N were common, accounting for 40% and 37% of unrelated alleles, respectively. The third mutation accounting for 20% of mutant alleles was p.R123X causing a premature stop codon, is thus considered to be severe, which is in accordance with the phenotype presented by the homozygous patient described here. The fourth mutation p.E271D was found in a single allele. More than half of our patients manifested some chronic neurological complications. CONCLUSIONS: This is the first report on mutational and phenotypic spectra of classic galactosemia in Croatia that expands the knowledge on the mutational map of the GALT gene across Europe and reveals the genetic homogeneity of the Croatian population.

Sweet and sour: an update on classic galactosemia.

Classic galactosemia is a rare inherited disorder of galactose metabolism caused by deficient activity of galactose-1-phosphate uridylyltransferase (GALT), the second enzyme of the Leloir pathway. It presents in the newborn period as a life-threatening disease, whose clinical picture can be resolved by a galactose-restricted diet. The dietary treatment proves, however, insufficient in preventing severe long-term complications, such as cognitive, social and reproductive impairments. Classic galactosemia represents a heavy burden on patients' and their families' lives. After its first description in 1908 and despite intense research in the past century, the exact pathogenic mechanisms underlying galactosemia are still not fully understood. Recently, new important insights on molecular and cellular aspects of galactosemia have been gained, and should open new avenues for the development of novel therapeutic strategies. Moreover, an international galactosemia network has been established, which shall act as a platform for expertise and research in galactosemia. Herein are reviewed some of the latest developments in clinical practice and research findings on classic galactosemia, an enigmatic disorder with many unanswered questions warranting dedicated research.

Data supporting the co-expression of PDHA1 gene and of its paralogue PDHA2 in somatic cells of a family.

This article presents a dataset proving the simultaneous presence of a 5'UTR-truncated PDHA1 mRNA and a full-length PDHA2 mRNA in the somatic cells of a PDC-deficient female patient and all members of her immediate family (parents and brother). We have designed a large set of primer pairs in order to perform detailed RT-PCR assays allowing the clear identification of both PDHA1 and PDHA2 mRNA species in somatic cells. In addition, two different experimental approaches were used to elucidate the copy number of PDHA1 gene in the patient and her mother. The interpretation and discussion of these data, along with further extensive experiments concerning the origin of this altered gene expression and its potential therapeutic consequences, can be found in "Complex genetic findings in a female patient with pyruvate dehydrogenase complex deficiency: null mutations in the PDHX gene associated with unusual expression of the testis-specific PDHA2 gene in her somatic cells" (A. Pinheiro, M.J. Silva, C. Florindo, et al., 2016) [1].

Complex genetic findings in a female patient with pyruvate dehydrogenase complex deficiency: Null mutations in the PDHX gene associated with unusual expression of the testis-specific PDHA2 gene in her somatic cells.

Human pyruvate dehydrogenase complex (PDC) catalyzes a key step in the generation of cellular energy and is composed by three catalytic elements (E1, E2, E3), one structural subunit (E3-binding protein), and specific regulatory elements, phosphatases and kinases (PDKs, PDPs). The E1α subunit exists as two isoforms encoded by different genes: PDHA1 located on Xp22.1 and expressed in somatic tissues, and the intronless PDHA2 located on chromosome 4 and only detected in human spermatocytes and spermatids. We report on a young adult female patient who has PDC deficiency associated with a compound heterozygosity in PDHX encoding the E3-binding protein. Additionally, in the patient and in all members of her immediate family, a full-length testis-specific PDHA2 mRNA and a 5'UTR-truncated PDHA1 mRNA were detected in circulating lymphocytes and cultured fibroblasts, being both mRNAs translated into full-length PDHA2 and PDHA1 proteins, resulting in the co-existence of both PDHA isoforms in somatic cells. Moreover, we observed that DNA hypomethylation of a CpG island in the coding region of PDHA2 gene is associated with the somatic activation of this gene transcription in these individuals. This study represents the first natural model of the de-repression of the testis-specific PDHA2 gene in human somatic cells, and raises some questions related to the somatic activation of this gene as a potential therapeutic approach for most forms of PDC deficiency.