Nontargeted urine metabolomic analysis of acute intermittent porphyria reveals novel interactions between bile acids and heme metabolism: New promising biomarkers for the long-term management of patients.

Acute intermittent porphyria is an inherited error of heme synthesis. The underlying pathophysiology, involving mainly hepatic heme synthesis, is poorly understood despite its occurrence, and the severity of acute porphyria attack is still difficult to control. A better understanding of the interactions between heme synthesis and global metabolism would improve the management of AIP patients. An untargeted metabolomic analysis was performed on the urine of 114 patients with overt AIP and asymptomatic carriers using liquid chromatography coupled to high-resolution mass spectrometry. The collected data were analyzed by combining univariate and multivariate analyses. A total of 239 metabolites were annotated in urine samples by matching chromatographic and mass spectral characteristics with those from our chemical library. Twenty-six metabolites, including porphyrin precursors, intermediates of tryptophan or glycine metabolism and, unexpectedly, bile acids, showed significant concentration differences between the phenotypic groups. Dysregulation of bile acid metabolism was confirmed by targeted quantitative analysis, which revealed an imbalance in favor of hydrophobic bile acids associated with changes in conjugation, which was more pronounced in the severe phenotype. Using a random forest model, the cholic acid/chenodeoxycholic acid ratio enables the differential classification of severe patients from other patients with a diagnostic accuracy of 84%. The analysis of urine samples revealed significant modifications in the metabolome of AIP patients. Alteration in bile acids provides new insights into the pathophysiology of chronic complications, such as primary liver cancer, while also providing new biomarker candidates for predicting the most severe phenotypes.

Quantification of Urine and Plasma Porphyrin Precursors Using LC-MS in Acute Hepatic Porphyrias: Improvement in Routine Diagnosis and in the Monitoring of Kidney Failure Patients.

BACKGROUND: The quantification of delta-aminolevulinic acid (ALA) and porphobilinogen (PBG) in urine are the first-line tests for diagnosis and monitoring of acute hepatic porphyrias (AHP). Ion-exchange chromatography (IEC), which is time- and staff-consuming and limited to urine, is still the preferred method in many specialized laboratories, despite the development of mass spectrometry-based methods. METHODS: We describe a new LC-MS method that allows for rapid and simple quantification of ALA and PBG in urine and plasma with an affordable instrument that was used to analyze 2260 urine samples and 309 blood samples collected in 2 years of routine activity. The results were compared to those obtained with IEC, and urine reference ranges and concentrations in asymptomatic carriers were determined. Plasma concentrations were measured in healthy subjects and subgroups of symptomatic and asymptomatic AHP carriers. RESULTS: In urine, the clinical decision limits were not impacted by the change of method despite discrepancies in low absolute concentrations, leading to lower normal values. Two-thirds of asymptomatic AHP carriers (with the exception of coproporphyria carriers) showed an increased urine PBG concentration. Urine and plasma levels showed a good correlation except in patients with kidney disease in whom the urine/plasma ratio was relatively low. CONCLUSION: We described an LC-MS based method for the routine diagnosis and monitoring of AHP that allows for the detection of more asymptomatic carriers than the historical method. Blood analysis appears to be particularly relevant for patients with kidney disease, where urine measurement underestimates the increase in ALA and PBG levels.

Erythroid-Progenitor-Targeted Gene Therapy Using Bifunctional TFR1 Ligand-Peptides in Human Erythropoietic Protoporphyria.

Erythropoietic protoporphyria (EPP) is a hereditary disease characterized by a deficiency in ferrochelatase (FECH) activity. FECH activity is responsible for the accumulation of protoporphyrin IX (PPIX). Without etiopathogenic treatment, EPP manifests as severe photosensitivity. 95% of affected individuals present a hypomorphic FECH allele trans to a loss-of-function (LOF) FECH mutation, resulting in a reduction in FECH activity in erythroblasts below a critical threshold. The hypomorphic allele promotes the use of a cryptic acceptor splice site, generating an aberrant FECH mRNA, which is responsible for the reduced level of wild-type FECH mRNA and, ultimately, FECH activity. We have previously identified an antisense oligonucleotide (AON), AON-V1 (V1), that redirects splicing to the physiological acceptor site and reduces the accumulation of PPIX. Here, we developed a specific strategy that uses transferrin receptor 1 (TRF1) as a Trojan horse to deliver V1 to erythroid progenitors. We designed a bifunctional peptide (P1-9R) including a TFR1-targeting peptide coupled to a nine-arginine cell-penetrating peptide (CPP) that facilitates the release of the AON from TFR1 in endosomal vesicles. We demonstrated that the P1-9R/V1 nanocomplex promotes the efficient and prolonged redirection of splicing towards the physiological splice site and subsequent normalization of WT FECH mRNA and protein levels. Finally, the P1-9R/V1 nanocomplex increases WT FECH mRNA production and significantly decreases PPIX accumulation in primary cultures of differentiating erythroid progenitors from an overt EPP-affected individual. P1-9R is a method designed to target erythroid progenitors and represents a potentially powerful tool for the in vivo delivery of therapeutic DNA in many erythroid disorders.

Givosiran in acute intermittent porphyria: A personalized medicine approach.

BACKGROUND: In patients with acute intermittent porphyria (AIP), induction of delta aminolevulinic acid synthase 1 (ALAS1) leads to haem precursor accumulation that may cause recurring acute attacks. In a recent phase III trial, givosiran significantly reduced the attack rate in severe AIP patients. Frequent adverse events were injection-site reaction, fatigue, nausea, chronic kidney disease and increased alanine aminotransferase. OBJECTIVES: To describe the efficacy and safety of givosiran based on a personalized medical approach. METHODS: We conducted a retrospective patient file study in 25 severe AIP patients treated with givosiran in France. We collected data on clinical and biochemical efficacy along with reports of adverse events. RESULTS: Givosiran drastically reduced the attack rate in our cohort, as 96% were attack-free at the time of the study. The sustained efficacy of givosiran in most patients allowed us to personalize dosing frequency. In 42%, givosiran was only given when haem precursor levels were increasing. Our data suggest that givosiran is most effective when given early in the disease course. We confirmed a high prevalence of adverse events. One patient discontinued treatment due to acute pancreatitis. All patients had hyperhomocysteinemia, and all patients with initial homocysteine levels available showed an increase under treatment. In this context, one patient was diagnosed with pulmonary embolism. CONCLUSION: The sustained effect of givosiran allowed a decrease in dosing frequency without compromising treatment efficacy. The high prevalence of adverse events emphasizes the importance of restricting the treatment to severe AIP and administering the minimum effective dose for each patient.

Phosphoglycerate dehydrogenase (PHGDH) deficiency without epilepsy mimicking primary microcephaly.

Phosphoglycerate dehydrogenase (PHGDH) deficiency (OMIM 256520) is a rare autosomal recessive disorder of serine synthesis, with mostly severe congenital microcephaly, caused by mutations in the PHGDH gene. Fourteen patients reported to date show severe, early onset, drug resistant epilepsy. In a cohort of patients referred for primary microcephaly, compound heterozygosity for two unreported variants in PHGDG was identified by exome sequencing in a pair of sibs who died aged 4.5 months and 4.5 years. They had severe neurological involvement with congenital microcephaly, disorganized EEG, and progressive spasticity, but never had seizures. Exome usage in clinical practice is likely to lead to an expansion of the clinical spectrum of known disorders.

Erythropoietic protoporphyrias: updates and advances.

Protoporphyrias are caused by pathogenic variants in genes encoding enzymes involved in heme biosynthesis. They induce the accumulation of a hydrophobic phototoxic compound, protoporphyrin (PPIX), in red blood cells (RBCs). PPIX is responsible for painful cutaneous photosensitivity, which severely impairs quality of life. Hepatic elimination of PPIX increases the risk of cholestatic liver disease, requiring lifelong monitoring. Treatment options are scarce and mainly limited to supportive care such as protection from visible light. Here, we review the pathophysiology of protoporphyrias, their diagnosis, and current recommendations for medical care. We discuss new therapeutic strategies, some of which are currently undergoing clinical trials and are likely to radically alter the severity of the disease in the years to come.

Successful treatment of congenital erythropoietic porphyria using matched unrelated hematopoietic stem cell transplantation in an adult: A case report.

Congenital erythropoietic porphyria (CEP), or Gunther disease, is a rare genetic disease responsible for severe dermatologic, hepatic and/or haematological damages related to the deficient activity of the uroporphyrinogen III synthase. Allogeneic stem cell transplantation (Allo-SCT) represents the only curative treatment and few allotransplanted cases have been reported in children but not in adults. Here we report for the first time the successful cure of a 46-year old man with CEP with a 5-year follow-up after Allo-SCT.

Severe Perinatal Presentations of Günther's Disease: Series of 20 Cases and Perspectives.

(1) Background: Congenital erythropoietic porphyria (CEP), named Günther's disease, is a rare recessive type of porphyria, resulting from deficient uroporphyrinogen III synthase (UROS), the fourth enzyme of heme biosynthesis. The phenotype ranges from extremely severe perinatal onset, with life-threatening hemolytic anaemia, to mild or moderate cutaneous involvement in late-onset forms. This work reviewed the perinatal CEP cases recorded in France in order to analyse their various presentations and evolution. (2) Methods: Clinical and biological data were retrospectively collected through medical and published records. (3) Results: Twenty CEP cases, who presented with severe manifestations during perinatal period, were classified according to the main course of the disease: antenatal features, acute neonatal distress and postnatal diagnosis. Antenatal symptoms (seven patients) were mainly hydrops fetalis, hepatosplenomegaly, anemia, and malformations. Six of them died prematurely. Five babies showed acute neonatal distress, associated with severe anemia, thrombocytopenia, hepatosplenomegaly, liver dysfunction, and marked photosensitivity leading to diagnosis. The only two neonates who survived underwent hematopoietic stem cell transplantation (HSCT). Common features in post-natal diagnosis (eight patients) included hemolytic anemia, splenomegaly, skin sensitivity, and discoloured teeth and urine. All patients underwent HSCT, with success for six of them, but with fatal complications in two patients. The frequency of the missense variant named C73R is striking in antenatal and neonatal presentations, with 9/12 and 7/8 independent alleles, respectively. (4) Conclusions: The most recent cases in this series are remarkable, as they had a less fatal outcome than expected. Regular transfusions from the intrauterine period and early access to HSCT are the main objectives.

Management of erythropoietic protoporphyria with cholestatic liver disease: A case report.

Erythropoietic protoporphyria (EPP) is a rare metabolic disease of the heme biosynthetic pathway where an enzymatic dysfunction results in protoporphyrin IX (PPIX) accumulation in erythroid cells. The porphyrins are photo-reactive and are responsible for severe photosensitivity in patients, thus drastically decreasing their quality of life. The liver eliminates PPIX and as such, the main and rare complication of EPP is progressive cholestatic liver disease, which can lead to liver failure. The management of this complication is challenging, as it often requires a combination of approaches to promote PPIX elimination and suppress the patient's erythropoiesis. Here we described a 3-year follow-up of an EPP patient, with three episodes of liver involvement, aggravated by the coexistence of a factor VII deficiency. It covers all the different types of intervention available for the management of liver disease, right through to successful allogeneic hematopoietic stem cell transplantation.

[Abnormal urine color assessment: The urine wheel]. / Orientation diagnostique devant une coloration anormale des urines : la roue à urines 2.0.

Looking at the urine for diagnostic purposes, once performed by ancient Egyptians, can still provide some valuable clues in modern medicine. Several diseases have been named after their associated urine color and this underlines the clinical value of visual urine inspection: blue diaper disease, purple urine bag syndrome, black urine disease or porphyria. Abnormal urine color could be challenging for the clinician: it may reveal neoplastic disease (urologic cancer; melanoma), cell lysis (rhabdomyolysis; hemolysis), infection (lymphatic filariasis; malaria), enzyme deficiency (porphyria; alkaptonuria), medication or food intake. In this article, we present the diagnostic approach, the mechanisms involved and the main causes of abnormal urine color.

Iron, Heme Synthesis and Erythropoietic Porphyrias: A Complex Interplay.

Erythropoietic porphyrias are caused by enzymatic dysfunctions in the heme biosynthetic pathway, resulting in porphyrins accumulation in red blood cells. The porphyrins deposition in tissues, including the skin, leads to photosensitivity that is present in all erythropoietic porphyrias. In the bone marrow, heme synthesis is mainly controlled by intracellular labile iron by post-transcriptional regulation: translation of ALAS2 mRNA, the first and rate-limiting enzyme of the pathway, is inhibited when iron availability is low. Moreover, it has been shown that the expression of ferrochelatase (FECH, an iron-sulfur cluster enzyme that inserts iron into protoporphyrin IX to form heme), is regulated by intracellular iron level. Accordingly, there is accumulating evidence that iron status can mitigate disease expression in patients with erythropoietic porphyrias. This article will review the available clinical data on how iron status can modify the symptoms of erythropoietic porphyrias. We will then review the modulation of heme biosynthesis pathway by iron availability in the erythron and its role in erythropoietic porphyrias physiopathology. Finally, we will summarize what is known of FECH interactions with other proteins involved in iron metabolism in the mitochondria.

Renal Function Decline With Small Interfering RNA Silencing Aminolevulinic Acid Synthase 1 (ALAS1).

INTRODUCTION: Givosiran is an RNA interference therapeutic designed to block the synthesis of the aminolevulinic acid (ALA) synthase 1 (ALAS1) enzyme in patients with acute intermittent porphyria (AIP). Givosiran may have adverse effects on the kidney. METHODS: We performed a descriptive case series of renal function parameters of all the patients who received givosiran in France. Twenty patients receiving givosiran between March 2018 and July 2020 in France were analyzed: 7 patients in the ENVISION trial and 13 patients treated in collaboration with the Centre de Référence Maladies Rares Prophyries. RESULTS: A transient decrease in renal function was observed in all but 2 patients (90%) within the 3 months following givosiran initiation. None of the patients developed acute kidney injury or disease. Patients of the ENVISION cohort were followed for at least 30 months: 2 patients did not experience estimated glomerular filtration rate (eGFR) loss, 3 patients experienced a modest decline in renal function (-3.4 ml/min per 1.73 m2 per year in average), and 2 patients had a clearly abnormal eGFR loss (-5.8 ml/min per 1.73 m2 per year in average). None of the patients had biochemical signs of active tubular or glomerular injury. One patient's kidney was biopsied without finding any signs of an active kidney disease and with normal ALAS1 tubular expression. CONCLUSIONS: Givosiran is associated with a transient moderate increase in serum creatinine (sCr) without sign of kidney injury. A long-term deleterious impact of ALAS1 inhibition on renal function is not excluded. Because AIP promotes chronic kidney disease, it is difficult to separate the long-term effects of givosiran from the natural progression of the renal disease.

Identification of novel UROS mutations in a patient with congenital erythropoietic porphyria and efficient treatment by phlebotomy.

Congenital erythropoietic porphyria (CEP) is an autosomal recessive disorder of the heme biosynthetic pathway that is characterized by uroporphyrinogen III synthase (UROS) deficiency and the accumulation of non-physiological isomer I porphyrins. These phototoxic metabolites predominantly produced by the erythron result in ineffective erythropoiesis, chronic hemolysis and splenomegaly, but they also disseminate in tissues causing bullous photosensitivity to UV light and skin fragility that may progress to scarring with photo mutilation. Therapeutic management is currently limited to supportive care and bone marrow transplantation is reserved for the most severe cases. We describe here a 26-year-old women previously diagnosed with CEP harbouring two novel UROS gene mutations whose pathogenic mechanism was investigated by extensive molecular analysis. Clinical features included disabling hypertrichosis and skin photosensitivity without hemolysis. The first and rate-limiting 5-aminolevulinate synthase 2 (ALAS2) enzyme controls heme synthesis and porphyrin production in erythroid cells, while iron availability modulates its expression through a post-transcriptional mechanism. We performed iterative phlebotomies over 26 months to induce iron depletion in the patient and investigated the effectiveness and tolerance of this cost-effective approach. We observed a progressive decrease in plasma ferritin and urinary porphyrins upon treatment without inducing anemia. The patient reported improved quality of life and photosensitivity. Our data confirm recent reports highlighting the benefit of iron restriction on the disease phenotype through a reduction in porphyrin accumulation. This new strategy may represent an efficient and well-tolerated treatment for CEP patients with skin involvement and limited hematological component if iron restriction is carefully monitored.

Loss of the neurodevelopmental disease-associated gene miR-146a impairs neural progenitor differentiation and causes learning and memory deficits.

BACKGROUND: Formation and maintenance of appropriate neural networks require tight regulation of neural stem cell proliferation, differentiation, and neurogenesis. microRNAs (miRNAs) play an important role in brain development and plasticity, and dysregulated miRNA profiles have been linked to neurodevelopmental disorders including autism, schizophrenia, or intellectual disability. Yet, the functional role of miRNAs in neural development and postnatal brain functions remains unclear. METHODS: Using a combination of cell biology techniques as well as behavioral studies and brain imaging, we characterize mouse models with either constitutive inactivation or selectively hippocampal knockdown of the neurodevelopmental disease-associated gene Mir146a, the most commonly deregulated miRNA in developmental brain disorders (DBD). RESULTS: We first show that during development, loss of miR-146a impairs the differentiation of radial glial cells, neurogenesis process, and neurite extension. In the mouse adult brain, loss of miR-146a correlates with an increased hippocampal asymmetry coupled with defects in spatial learning and memory performances. Moreover, selective hippocampal downregulation of miR-146a in adult mice causes severe hippocampal-dependent memory impairments indicating for the first time a role for this miRNA in postnatal brain functions. CONCLUSION: Our results show that miR-146a expression is critical for correct differentiation of neural stem cell during brain development and provide for the first time a strong argument for a postnatal role of miR-146a in regulating hippocampal-dependent memory. Furthermore, the demonstration that the Mir146a-/- mouse recapitulates several aspects reported in DBD patients, including impaired neurogenesis, abnormal brain anatomy, and working and spatial memories deficits, provides convincing evidence that the dysregulation of miR146a contributes to the pathogenesis of DBDs.

Hereditary breast and ovarian cancer: successful systematic implementation of a group approach to genetic counselling.

The increase in referrals to cancer genetics clinics, partially associated with the "Angelina Jolie effect", presents a challenge to existing services, many are already running at full capacity. More efficient ways to deliver genetic counselling are therefore urgently needed. We now systematically offer group instead of standard individual counselling to patients with suspected Hereditary Breast and Ovarian Cancer. Group sessions last 30 min. The first twenty consist of a presentation by the genetic counsellor, the next ten of a discussion involving a cancer geneticist and a psychologist. A short individual consultation ensues, where personal and family issues are addressed and consent obtained. Blood is drawn afterwards. Satisfaction and knowledge are evaluated. We report data for the Oct-2014-Aug-2015 period. 210 patients attended group counselling, up to eight simultaneously. We always fitted them within a 4-h time frame. Mean satisfaction score was 41/43. Knowledge scores increased from 3.1/6 to 4.9/6 post-counselling (p value < 2.2 × 10-16). Thanks to group counselling, we have withstood increases in referrals without compromising care. The "Angelina Jolie effect" and rapid developments in personalized medicine threaten to overwhelm cancer genetics clinics. In this context, our innovative approach should ensure that all patients have access to approved services.

The lactase persistence genotype is associated with body mass index and dairy consumption in the D.E.S.I.R. study.

OBJECTIVE: The T allele of a functional polymorphism (rs4988235: LCT-13910 C>T), close to the lactase gene, correlates with lactase persistence (LP) in adults. The LP genotype (TT+TC) has been associated with a higher BMI in European populations in cross-sectional studies. In the French D.E.S.I.R. cohort, a high consumption of dairy products was associated with a lower body weight gain over 9-years, and with a lower incidence of high plasma glucose levels and/or the metabolic syndrome. Our aim was to test in this study, the association of rs4988235 with BMI and related metabolic diseases, in interaction with dairy product consumption. METHODS: Among 5212 subjects from D.E.S.I.R., 3575 Caucasians born in mainland France were genotyped and followed over 9years. RESULTS: Those with the LP genotype (frequency: 78.5%) had a higher dairy product consumption, at inclusion and at year-9 (P<0.001). They also had a higher BMI at both time points (difference=0.3kg/m(2), P=0.05), but this effect was restricted to medium/high dairy product consumers (difference=0.5kg/m(2), P=0.006). This genotype was also associated with the metabolic syndrome (IDF definition), but this association disappeared after adjustment for BMI. In the whole population, the C allele was associated with a higher prevalence of impaired fasting glycemia and/or type 2 diabetes. CONCLUSIONS: The lactase persistence genotype was shown to be associated with a higher BMI in a longitudinal study, mainly in those consuming high amounts of dairy products. The association of the C allele, responsible for lactase non-persistence, with the risk of hyperglycemia needs to be replicated.