Neurological Sequelae due to Inborn Metabolic Diseases in Pediatric Refugees: Challenges in Treating the Untreated.

In the 2015 mass migration from Syria and neighboring countries, Germany received an unprecedented number of 4,76,649 asylum applications. As many of the refugees arrived in Southern Germany via the Austrian border, the city of Munich was faced with the majority of Germany's inflow of war refugees and their complex health issues. Among the refugees were a high number of children. Their main health issues were infectious diseases and surgical procedures due to trauma, but we also encountered complex chronic diseases. This report describes clinical history, signs and symptoms, diagnostics, and treatment of six pediatric patients with untreated inborn errors of metabolism (IEM): phenylketonuria, biotinidase deficiency, HMG-CoA lyase deficiency, mucopolysaccharidosis type II, and mucopolysaccharidosis type VI. Since early diagnosis and treatment is essential in IEM, both delayed diagnosis and inadequate therapy in refugee children may lead to significant brain injury, organ damage, and even death. Severe neurological sequelae in both phenylketonuria and HMG-CoA lyase deficiency could have been prevented by newborn screening. Screening programs are necessary to improve the prognoses for refugee children. European Union governments and involved health care systems should pursue early diagnosis and treatment in pediatric refugees regarding IEM to prevent neurological long-term sequelae.

On Seizing the Source: Toward a Phenomenology of Religious Violence.

In this paper I argue that we need to analyze 'religious violence' in the 'post-secular context' in a twofold way: rather than simply viewing it in terms of mere irrationality, senselessness, atavism, or monstrosity - terms which, as we witness today on an immense scale, are strongly endorsed by the contemporary theater of cruelty committed in the name of religion - we also need to understand it in terms of an 'originary supplement' of 'disengaged reason'. In order to confront its specificity beyond traditional explanations of violence, I propose an integrated phenomenological account of religion that traces the phenomenality of religion in terms of a correlation between the originary givenness of transcendence and capable man's creative capacities to respond to it. Following Ricœur, I discuss 'religious violence' in terms of a monopolizing appropriation of the originary source of givenness that conflates man's freedom to poetically respond to the appeal of the foundational with the surreptitiously claimed sovereignty to make it happen in a practical transfiguration of the everyday.

Innovative strategies to treat protein misfolding in inborn errors of metabolism: pharmacological chaperones and proteostasis regulators.

To attain functionality, proteins must fold into their three-dimensional native state. The intracellular balance between protein synthesis, folding, and degradation is constantly challenged by genetic or environmental stress factors. In the last ten years, protein misfolding induced by missense mutations was demonstrated to be the seminal molecular mechanism in a constantly growing number of inborn errors of metabolism. In these cases, loss of protein function results from early degradation of missense-induced misfolded proteins. Increasing knowledge on the proteostasis network and the protein quality control system with distinct mechanisms in different compartments of the cell paved the way for the development of new treatment strategies for conformational diseases using small molecules. These comprise proteostasis regulators that enhance the capacity of the proteostasis network and pharmacological chaperones that specifically bind and rescue misfolded proteins by conformational stabilization. They can be used either alone or in combination, the latter to exploit synergistic effects. Many of these small molecule compounds currently undergo preclinical and clinical pharmaceutical development and two have been approved: saproterin dihydrochloride for the treatment of phenylketonuria and tafamidis for the treatment of transthyretin-related hereditary amyloidosis. Different technologies are exploited for the discovery of new small molecule compounds that belong to the still young class of pharmaceutical products discussed here. These compounds may in the near future improve existing treatment strategies or even offer a first-time treatment to patients suffering from nowadays-untreatable inborn errors of metabolism.

Towards a Relational Phenomenology of Violence.

This article elaborates a relational phenomenology of violence. Firstly, it explores the constitution of all sense in its intrinsic relation with our embodiment and intercorporality. Secondly, it shows how this relational conception of sense and constitution paves the path for an integrative understanding of the bodily and symbolic constituents of violence. Thirdly, the author addresses the overall consequences of these reflections, thereby identifying the main characteristics of a relational phenomenology of violence. In the final part, the paper provides an exemplification of the outlined conception with regard to a concrete phenomenon of violence, i.e., slapping, and a concluding reflection upon its overall significance for research on violence.

From the "metaphysics of the individual" to the critique of society: on the practical significance of Michel Henry's phenomenology of life.

This essay explores the practical significance of Michel Henry's "material phenomenology." Commencing with an exposition of his most basic philosophical intuition, i.e., his insight that transcendental affectivity is the primordial mode of revelation of our selfhood, the essay then brings to light how this intuition also establishes our relation to both the world and others. Animated by a radical form of the phenomenological reduction, Henry's material phenomenology brackets the exterior world in a bid to reach the concrete interior transcendental experience at the base of all exteriority. The essay argues that this "counter reduction," designed as a practical orientation to the world, suspends all traditional parameters of onto(theo)logical individuation in order to rethink subjectivity in terms of its transcendental corporeality, i.e., in terms of the invisible display of "affective flesh." The development of this "metaphysics of the individual" anchors his "practical philosophy" as he developed it-under shifting accents-throughout his oeuvre. In particular, the essay brings into focus Henry's reflections on modernity, the industry of mass culture and their "barbaric" movements. The essay briefly puts these cultural and political areas of Henry's of thinking into contact with his late "theological turn," i.e., his Christological account of Life and the (inter)subjective self-realization to which it gives rise.

Racism: On the phenomenology of embodied desocialization.

This paper addresses racism from a phenomenological viewpoint. Its main task is, ultimately, to show that racism as a process of "negative socialization" does not amount to a contingent deficiency that simply disappears under the conditions of a fully integrated society. In other words, I suspect that racism does not only indicate a lack of integration, solidarity, responsibility, recognition, etc.; rather, that it is, in its extraordinary negativity, a socially constitutive phenomenon per se. After suggesting phenomenology's potential to tackle the question of racism, I will focus on the experiential oppressiveness of racism, i.e., the ways in which it affects its victims' lived experiences, in transforming their habitual ways of life and, finally, their subjectivities. My major thesis is that racism works via both inter-kinaesthetically as well as symbolically inflicted distortions of the victim's body schema. As such a process of "negative socialization," racism, however, influences the embodied self-conception of the oppressor, who finds himself compelled to adhere to some kind of invisible norm such as, e.g., "whiteness."

The interplay between genotype, metabolic state and cofactor treatment governs phenylalanine hydroxylase function and drug response.

The discovery of a pharmacological treatment for phenylketonuria (PKU) raised new questions about function and dysfunction of phenylalanine hydroxylase (PAH), the enzyme deficient in this disease. To investigate the interdependence of the genotype, the metabolic state (phenylalanine substrate) and treatment (BH(4) cofactor) in the context of enzyme function in vitro and in vivo, we (i) used a fluorescence-based method for fast enzyme kinetic analyses at an expanded range of phenylalanine and BH(4) concentrations, (ii) depicted PAH function as activity landscapes, (iii) retraced the analyses in eukaryotic cells, and (iv) translated this into the human system by analyzing the outcome of oral BH(4) loading tests. PAH activity landscapes uncovered the optimal working range of recombinant wild-type PAH and provided new insights into PAH kinetics. They demonstrated how mutations might alter enzyme function in the space of varying substrate and cofactor concentrations. Experiments in eukaryotic cells revealed that the availability of the active PAH enzyme depends on the phenylalanine-to-BH(4) ratio. Finally, evaluation of data from BH(4) loading tests indicated that the patient's genotype influences the impact of the metabolic state on drug response. The results allowed for visualization and a better understanding of PAH function in the physiological and pathological state as well as in the therapeutic context of cofactor treatment. Moreover, our data underscore the need for more personalized procedures to safely identify and treat patients with BH(4)-responsive PAH deficiency.

New insights into tetrahydrobiopterin pharmacodynamics from Pah enu1/2, a mouse model for compound heterozygous tetrahydrobiopterin-responsive phenylalanine hydroxylase deficiency.

Phenylketonuria (PKU), an autosomal recessive disease with phenylalanine hydroxylase (PAH) deficiency, was recently shown to be a protein misfolding disease with loss-of-function. It can be treated by oral application of the natural PAH cofactor tetrahydrobiopterin (BH(4)) that acts as a pharmacological chaperone and rescues enzyme function in vivo. Here we identified Pah(enu1/2) bearing a mild and a severe mutation (V106A/F363S) as a new mouse model for compound heterozygous mild PKU. Although BH(4) treatment has become established in clinical routine, there is substantial lack of knowledge with regard to BH(4) pharmacodynamics and the effect of the genotype on the response to treatment with the natural cofactor. To address these questions we applied an elaborate methodological setup analyzing: (i) blood phenylalanine elimination, (ii) blood phenylalanine/tyrosine ratios, and (iii) kinetics of in vivo phenylalanine oxidation using (13)C-phenylalanine breath tests. We compared pharmacodynamics in wild-type, Pah(enu1/1), and Pah(enu1/2) mice and observed crucial differences in terms of effect size as well as effect kinetics and dose response. Results from in vivo experiments were substantiated in vitro after overexpression of wild-type, V106A, and F263S in COS-7 cells. Pharmacokinetics did not differ between Pah(enu1/1) and Pah(enu1/2) indicating that the differences in pharmacodynamics were not induced by divergent pharmacokinetic behavior of BH(4). In conclusion, our findings show a significant impact of the genotype on the response to BH(4) in PAH deficient mice. This may lead to important consequences concerning the diagnostic and therapeutic management of patients with PAH deficiency underscoring the need for individualized procedures addressing pharmacodynamic aspects.

Activation of phenylalanine hydroxylase induces positive cooperativity toward the natural cofactor.

Protein misfolding with loss-of-function of the enzyme phenylalanine hydroxylase (PAH) is the molecular basis of phenylketonuria in many individuals carrying missense mutations in the PAH gene. PAH is complexly regulated by its substrate L-Phenylalanine and its natural cofactor 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (BH(4)). Sapropterin dihydrochloride, the synthetic form of BH(4), was recently approved as the first pharmacological chaperone to correct the loss-of-function phenotype. However, current knowledge about enzyme function and regulation in the therapeutic setting is scarce. This illustrates the need for comprehensive analyses of steady state kinetics and allostery beyond single residual enzyme activity determinations to retrace the structural impact of missense mutations on the phenylalanine hydroxylating system. Current standard PAH activity assays are either indirect (NADH) or discontinuous due to substrate and product separation before detection. We developed an automated fluorescence-based continuous real-time PAH activity assay that proved to be faster and more efficient but as precise and accurate as standard methods. Wild-type PAH kinetic analyses using the new assay revealed cooperativity of activated PAH toward BH(4), a previously unknown finding. Analyses of structurally preactivated variants substantiated BH(4)-dependent cooperativity of the activated enzyme that does not rely on the presence of l-Phenylalanine but is determined by activating conformational rearrangements. These findings may have implications for an individualized therapy, as they support the hypothesis that the patient's metabolic state has a more significant effect on the interplay of the drug and the conformation and function of the target protein than currently appreciated.

Pahenu1 is a mouse model for tetrahydrobiopterin-responsive phenylalanine hydroxylase deficiency and promotes analysis of the pharmacological chaperone mechanism in vivo.

The recent approval of sapropterin dihydrochloride, the synthetic form of 6[R]-l-erythro-5,6,7,8-tetrahydrobiopterin (BH(4)), for the treatment of phenylketonuria (PKU) as the first pharmacological chaperone drug initiated a paradigm change in the treatment of monogenetic diseases. Symptomatic treatment is now replaced by a causal pharmacological therapy correcting misfolding of the defective phenylalanine hydroxylase (PAH) in numerous patients. Here, we disclose BH(4) responsiveness in Pah(enu1), a mouse model for PAH deficiency. Loss of function resulted from loss of PAH, a consequence of misfolding, aggregation, and accelerated degradation of the enzyme. BH(4) attenuated this triad by conformational stabilization augmenting the effective PAH concentration. This led to the rescue of the biochemical phenotype and enzyme function in vivo. Combined in vitro and in vivo analyses revealed a selective pharmaceutical action of BH(4) confined to the pathological metabolic state. Our data provide new molecular-level insights into the mechanisms underlying protein misfolding with loss of function and support a general model of pharmacological chaperone-induced stabilization of protein conformation to correct this intracellular phenotype. Pah(enu1) will be essential for pharmaceutical drug optimization and to design individually tailored therapies.

Loss of function in phenylketonuria is caused by impaired molecular motions and conformational instability.

A significant share of patients with phenylalanine hydroxylase (PAH) deficiency benefits from pharmacological doses of tetrahydrobiopterin (BH(4)), the natural PAH cofactor. Phenylketonuria (PKU) is hypothesized to be a conformational disease, with loss of function due to protein destabilization, and the restoration of enzyme function that is observed in BH(4) treatment might be transmitted by correction of protein misfolding. To elucidate the molecular basis of functional impairment in PAH deficiency, we investigated the impact of ten PAH gene mutations identified in patients with BH(4)-responsiveness on enzyme kinetics, stability, and conformation of the protein (F55L, I65S, H170Q, P275L, A300S, S310Y, P314S, R408W, Y414C, Y417H). Residual enzyme activity was generally high, but allostery was disturbed in almost all cases and pointed to altered protein conformation. This was confirmed by reduced proteolytic stability, impaired tetramer assembly or aggregation, increased hydrophobicity, and accelerated thermal unfolding--with particular impact on the regulatory domain--observed in most variants. Three-dimensional modeling revealed the involvement of functionally relevant amino acid networks that may communicate misfolding throughout the protein. Our results substantiate the view that PAH deficiency is a protein-misfolding disease in which global conformational changes hinder molecular motions essential for physiological enzyme function. Thus, PKU has evolved from a model of a genetic disease that leads to severe neurological impairment to a model of a treatable protein-folding disease with loss of function.