Acute Intermittent Porphyria Patients Research Articles

Potential Biomarkers for the Earlier Diagnosis of Kidney and Liver Damage in Acute Intermittent Porphyria.

Acute intermittent porphyria (AIP) is an inherited metabolic disorder associated with complications including kidney failure and hepatocellular carcinoma, probably caused by elevations in the porphyrin precursors porphobilinogen (PBG) and delta-aminolevulinic acid (ALA). This study explored differences in modern biomarkers for renal and hepatic damage between AIP patients and controls. Urine PBG testing, kidney injury panels, and liver injury panels, including both routine and modern biomarkers, were performed on plasma and urine samples from AIP cases and matched controls (50 and 48 matched pairs, respectively). Regarding the participants' plasma, the AIP cases had elevated kidney injury marker-1 (KIM-1, p = 0.0002), fatty acid-binding protein-1 (FABP-1, p = 0.04), and α-glutathione S-transferase (α-GST, p = 0.001) compared to the matched controls. The AIP cases with high PBG had increased FABP-1 levels in their plasma and urine compared to those with low PBG. In the AIP cases, KIM-1 correlated positively with PBG, CXCL10, CCL2, and TCC, and the liver marker α-GST correlated positively with IL-13, CCL2, and CCL4 (all p < 0.05). In conclusion, KIM-1, FABP-1, and α-GST could represent potential early indicators of renal and hepatic damage in AIP, demonstrating associations with porphyrin precursors and inflammatory markers.

Functional and structural analysis of a novel splice site HMBS variant in a Chinese AIP patient.

Background: Acute intermittent porphyria (AIP) is a rare metabolic disorder that results from mutations in the gene encoding hydroxymethylbilane synthase (HMBS), an enzyme involved in heme biosynthesis. AIP follows an autosomal dominant inheritance pattern, but most carriers are asymptomatic. The clinical manifestations of AIP include acute attacks of abdominal pain and neuropsychiatric disturbances. The pathogenicity of novel HMBS variants identified in Chinese patients has not been well established. Objective: The article aims to identify the pathogenic mutation in an AIP patient and prove its pathogenicity through in vitro experiments. Methods: A 22-year-old female diagnosed with AIP participated in the study. Variant screening of her HMBS gene was carried out through Sanger sequencing. To ascertain the consequences of the newly discovered variant, we conducted in vitro experimentation targeting HMBS gene expression and enzymatic function. Additionally, protein structure analysis was performed. Cycloheximide treatment and UPF1-specific siRNA knockdown were employed to assess the impact of the mutation on the mechanism of non-sense-mediated mRNA decay (NMD). Results: A novel splice site variant in the HMBS gene (c.648_651+1delCCAGG) was detected in the patient, which caused aberrant mRNA splicing. In vitro experiments demonstrated that this variant significantly decreased the expression of HMBS. Further investigation confirmed that this decrease was due to NMD. Additionally, structural analysis indicated that this variant would destabilize the HMBS protein and impair its catalytic activity. To gain a comprehensive understanding of HMBS mutations in the context of AIP, we conducted a literature search on PubMed using the keywords 'HMBS' and 'Acute intermittent porphyria' from 2013 to 2023. This search yielded 19 clinical case reports written in English, which collectively described 220 HMBS gene mutations worldwide. Conclusion: The study identified and proved the pathogenicity of a novel splice site HMBS variant for the first time. Our results elucidated the pathological mechanism by which this mutation causes AIP through reducing HMBS expression and activity. These findings provide theoretical guidance for the diagnosis, treatment and genetic counseling of AIP patients.

Mitochondrial DNA Copy Number Drives the Penetrance of Acute Intermittent Porphyria.

No published study has investigated the mitochondrial count in patients suffering from acute intermittent porphyria (AIP). In order to determine whether mitochondrial content can influence the pathogenesis of porphyria, we measured the mitochondrial DNA (mtDNA) copy number in the peripheral blood cells of 34 patients and 37 healthy individuals. We found that all AIP patients had a low number of mitochondria, likely as a result of a protective mechanism against an inherited heme synthesis deficiency. Furthermore, we identified a close correlation between disease penetrance and decreases in the mitochondrial content and serum levels of PERM1, a marker of mitochondrial biogenesis. In a healthy individual, mitochondrial count is usually modulated to fit its ability to respond to various environmental stressors and bioenergetic demands. In AIP patients, coincidentally, the phenotype only manifests in response to endogenous and exogenous triggers factors. Therefore, these new findings suggest that a deficiency in mitochondrial proliferation could affect the individual responsiveness to stimuli, providing a new explanation for the variability in the clinical manifestations of porphyria. However, the metabolic and/or genetic factors responsible for this impairment remain to be identified. In conclusion, both mtDNA copy number per cell and mitochondrial biogenesis seem to play a role in either inhibiting or promoting disease expression. They could serve as two novel biomarkers for porphyria.

Transcriptome profile analysis reveals putative molecular mechanisms of 5-aminolevulinic acid toxicity

5-aminolevulinic acid (5-ALA) is the first precursor of the heme biosynthesis pathway, accumulated in acute intermittent porphyria (AIP), an inherited metabolic disease characterized by porphobilinogen deaminase deficiency. An increased incidence of hepatocellular carcinoma (HCC) has been reported as a long-term manifestation in symptomatic AIP patients. 5-ALA is an α-aminoketone prone to oxidation, yielding reactive oxygen species and 4,5-dioxovaleric acid. A high concentration of 5-ALA presents deleterious pro-oxidant potential. It can induce apoptosis, DNA damage, mitochondrial dysfunction, and altered expression of carcinogenesis-related proteins. Several hypotheses of the increased risk of HCC rely on the harmful effect of elevated 5-ALA in the liver of AIP patients, which could promote a pro-carcinogenic environment. We investigated the global transcriptional changes and perturbed molecular pathways in HepG2 cells following exposure to 5-ALA 25 mM for 2 h and 24 h using DNA microarray. Distinct transcriptome profiles were observed. 5-ALA ’25 mM-2h′ upregulated 10 genes associated with oxidative stress response and carcinogenesis. Enrichment analysis of differentially expressed genes by KEGG, Reactome, MetaCore™, and Gene Ontology, showed that 5-ALA ‘25 mM-24h’ enriched pathways involved in drug detoxification, oxidative stress, DNA damage, cell death/survival, cell cycle, and mitochondria dysfunction corroborating the pro-oxidant properties of 5-ALA. Furthermore, our results disclosed other possible processes such as senescence, immune responses, endoplasmic reticulum stress, and also some putative effectors, such as sequestosome, osteopontin, and lon peptidase 1. This study provided additional knowledge about molecular mechanisms of 5-ALA toxicity which is essential to a deeper understanding of AIP and HCC pathophysiology. Furthermore, our findings can contribute to improving the efficacy of current therapies and the development of novel biomarkers and targets for diagnosis, prognosis, and therapeutic strategies for AHP/AIP and associated HCC.

Research Progress in Pathogenesis of Hypertension in Acute Intermittent Porphyria

Acute intermittent porphyria (AIP) has complicated clinical manifestations and is often accompanied by hypertension.AIP may cause hypertension through adrenergic effect,heme deficiency,inflammation,inappropriate secretion of antidiuretic hormone,toxicity of delta-aminolevulinic acid(ALA,aporphyrin precursor),and elevated serum glucose level.The prevention and treatment strategies for AIP accompanied with hypertension mainly include the controlling of porphyria attacks,application of antihypertensive drugs,lifestyle intervention,and management of latent AIP patients.

A 25-Hour Fast Among Quiescent Hereditary Coproporphyria and Variegate Porphyria Patients is Associated With a Low Risk of Complications

In patients with acute hepatic porphyria (AHP), prolonged fasting is a known trigger of AHP attacks. Despite this, some Jewish AHP patients-mainly hereditary coproporphyria (HCP) and variegate porphyria (VP) patients-fast for 25 consecutive hours during the traditional Jewish holy day known as Yom Kippur. In this study, we evaluated the effect of the fast on these patients. A retrospective study and survey of AHP patients in Israel was carried out. Patients were asked whether they have fasted and whether any symptoms were induced by this fast. Patients' medical records were reviewed for an emergency department (ED) visit following Yom Kippur between 2007 and 2019. Only 3 acute intermittent porphyria (AIP) patients reported fasting; they were excluded from analysis. A total of 21 HCP patients and 40 VP patients completed the survey; 30 quiescent patients reported they fast, while 31 did not fast. The majority of fasting patients (96.67%) reported no symptoms following a fast. We found no statistically significant association between ED visits 1 week (0.26% in both fasting and non-fasting patients) or 1 month (2.1% visits in non-fasting versus 0.78% in fasting patients) following Yom Kippur. Of the symptomatic ED visits following a fast, none were defined as severe attacks. A 25-hour fast in stable HCP and VP patients did not increase the risk of an acute attack and can probably be regarded as safe.

Mortality in Pedigrees with Acute Intermittent Porphyria.

High mortality rates have been reported in historical cohorts of acute intermittent porphyria (AIP) patients. The mortality associated with (hydroxymethylbilane synthase) HMBS variant heterozygosity is unknown. This study estimates all-cause mortality in pedigrees with HMBS gene variants that cause AIP. We collected data on the lifespan of individuals in Dutch AIP pedigrees and performed analyses using the family tree mortality ratio method. This gave us standardized mortality ratios for these pedigrees compared to the Dutch general population as a primary outcome. Between 1810 and 2017, the overall mortality in these pedigrees was identical to that of the general Dutch population: (SMR 1.01, p = 0.441). However, compared with the general population the SMR was significantly higher in women aged 45-64 years (SMR 1.99, p = 0.00003), which was based on excess mortality between 1915 and 1964 (SMR 1.94, p &lt; 0.00002). In men aged 70-74 years, the SMR was 1.55 (p = 0.0021), based on excess mortality that occurred between 1925 and 1964 (SMR 1.92, p = 0000000003). Overall, mortality from HMBS variant heterozygosity was not increased compared with the general population. Severe excess mortality occurred in young women and old men between 1915 and 1964. Heterozygotes reached a normal lifespan during the past half-century, in parallel with disease awareness and the prevention of new attacks through family counselling.

Novel Mutation of Hydroxymethylbilane Synthase in a Case of Acute Intermittent Porphyria Presenting with Posterior Reversible Encephalopathy Syndrome.

Acute intermittent porphyria (AIP) is an autosomal, dominant, hereditary metabolic disease caused by an inherited deficiency of hydroxymethylbilane synthase (HMBS), a crucial enzyme in the heme biosynthetic pathway. It can affect the central, peripheral, and autonomic nervous systems. We report a 23-year Chinese woman who presented with severe abdominal pain, convulsions, constipation, tachycardia, quadriparesis, and hyponatremia, accompanied by posterior reversible encephalopathy syndrome (PRES). The clinical diagnosis of AIP was made after positive urine Watson-Schwartz test for porphobilinogen (PBG). Genetic testing is important for AIP patients in confirming the diagnosis. We identified a new insertion mutation in intron 14 [c.1005dupC (p.I336Hfs*23)] of the HMBS in her genomic DNA. Timely and accurate treatment of AIP may improve disease prognosis. Key Words: Acute intermittent porphyria, Mutation, Posterior reversible encephalopathy syndrome.

Dental and Periodontal Health in Acute Intermittent Porphyria.

In the inherited metabolic disorder acute intermittent porphyria (AIP), high sugar intake prevents porphyric attacks due to the glucose effect and the following high insulin levels that may lower AIP disease activity. Insulin resistance is a known risk factor for periodontitis and sugar changes diabetogenic hormones and affects dental health. We hypothesized differences in homeostasis model assessment (HOMA) scores for insulin resistance in AIP cases vs. controls and in those with periodontitis. Our aim was to systematically study dental health in AIP as poor dental health was previously only described in case reports. Further, we aimed to examine if poor dental health and kidney failure might worsen AIP as chronic inflammation and kidney failure might increase disease activity. In 47 AIP cases and 47 matched controls, X-rays and physical examination of clinical attachment loss (CAL), probing pocket depth (PPD), and decayed missing filled teeth (DMFT) were performed. Dietary intake was evaluated through a diet logbook. Plasma cytokines and diabetogenic hormones were measured using multiplex technology and urine porphobilinogen and kidney and liver function by routine methods. An excel spreadsheet from the University of Oxford was used to estimate HOMA scores; beta cell function, HOMA%B (%B), insulin sensitivity, HOMA%S (%S), and insulin resistance HOMA-IR (IR), based on glucose and plasma (P) C-peptide. The Wilcoxon matched-pairs signed rank test, the Mann–Whitney U-test, and Spearman’s non-parametric correlation were used. Insulin (p = 0.007) and C-peptide (p = 0.006) were higher in the AIP cases with periodontitis versus those without. In AIP patients, the liver fibrosis index 4 correlated with DMFT (p < 0.001) and CAL ≥4 mm (p = 0.006); the estimated glomerular filtration rate correlated with DMFT (p < 0.001) and CAL ≥4 mm (p = 0.02). CAL ≥4 mm was correlated with chemokine ligand 11 and interleukin (IL)-13 (p = 0.04 for both), and PPD >5 mm was correlated with plasminogen activator inhibitor-1 (p = 0.003) and complement component 3 (p = 0.02). In conclusion, dental health in AIP cases was correlated with insulin resistance, inflammatory markers, and biomarkers of kidney and liver function, demonstrating that organ damage in the kidney and liver are associated with poorer dental health.

Acute intermittent porphyria: prevalence of pathogenic HMBS variants in China, and epidemiological survey in Hebei Province, China.

BackgroundAcute intermittent porphyria (AIP) is a rare inherited disorder with extremely low prevalence. Early detection of patients with potential pathogenic hydroxymethylbilane synthase (HMBS) variants is crucial for clinical prognosis. This study was designed to investigate the prevalence of pathogenic HMBS variants in Chinese population.MethodsThe China Metabolic Analysis Project (ChinaMAP) database was employed to predict the prevalence of pathogenic HMBS variants in the Chinese population according to the variant interpretation guidelines of The American College of Medical Genetics and Genomics (ACMG). And the prevalence of pathogenic HMBS variants in Mixed American (AMR), African/African American (AFR), and Non-Finnish European (NFE) populations were estimated based on the Genome Aggregation Database (gnomAD) genome V3.0 database according to the guidelines of ACMG. An epidemiological investigation of AIP was conducted in Hebei Province, China through collecting the annual newly-diagnosed AIP cases of inpatients in 32 comprehensive grade III A hospitals from January 2011 to December 2020 in Hebei, China.ResultsA total of 5 pathogenic/likely pathogenic (P/LP) HMBS variants were identified and the prevalence of pathogenic HMBS variants was predicted to be 1/1,765. Furthermore, based on the gnomAD genome V3.0 database, the estimated prevalence of pathogenic HMBS variants was 1/1,367, 1/1,403, and 1/621 in AMR, AFR, and NFE populations, respectively. The distribution of these variants varied among different racial populations. Moreover, AIP patients were predominantly hospitalized in comprehensive grade III A tertiary hospitals in Hebei province over a 10-year period. A total of 39 patients were newly-diagnosed with AIP, and a majority of them were female (n=36). The annual incidence between 2011 and 2017 {0.03 [95% confidence interval (CI): 0.01 to 0.11] to 0.05 (95% CI: 0.07 to 0.14) per million population} was generally lower than [0.07 (95% CI: 0.03 to 0.17) to 0.08 (95% CI: 0.03 to 0.18) per million] in 2018 and thereafter.ConclusionsChina has made great strides in the management of AIP. More nationwide epidemiological surveys and study of the prevalence rate of AIP patients in China are urgently required.

Evaluation of Metabolic Changes in Acute Intermittent Porphyria Patients by Targeted Metabolomics.

Acute intermittent porphyria (AIP) is an inherited rare hepatic disorder due to mutations within the hydroxymethylbilane gene. AIP patients with active disease overproduce aminolevulinic acid (ALA) and porphobilinogen (PBG) in the liver which are exported inducing severe neurological attacks. Different hepatic metabolic abnormalities have been described to be associated with this condition. The goal of this research was to explore the metabolome of symptomatic AIP patients by state-of-the art liquid chromatography-tandem mass spectrometry (LC-MS/MS). A case versus control study including 18 symptomatic AIP patients and 33 healthy controls was performed. Plasmatic levels of 51 metabolites and 16 ratios belonging to four metabolic pathways were determined. The results showed that the AIP patients presented significant changes in the two main areas of the metabolome under study: (a) the tryptophan/kynurenine pathway with an increase of tryptophan in plasma together with increase of the kynurenine/tryptophan ratio; and (b) changes in the tricarboxylic acid cycle (TCA) including increase of succinic acid and decrease of the fumaric acid/succinic acid ratio. We performed a complementary in vitro study adding ALA to hepatocytes media that showed some of the effects on the TCA cycle were parallel to those observed in vivo. Our study confirms in plasma previous results obtained in urine showing that AIP patients present a moderate increase of the kynurenine/tryptophan ratio possibly associated with inflammation. In addition, it also reports changes in the mitochondrial TCA cycle that, despite requiring further research, could be associated with an energy misbalance due to sustained overproduction of heme-precursors in the liver.

Givosiran in acute intermittent porphyria: A personalized medicine approach.

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. To describe the efficacy and safety of givosiran based on a personalized medical approach. 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. 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. 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.

Neurological Manifestations and Neuroimaging Findings of Acute Intermittent Porphyria Patients

Neurological Manifestations and Neuroimaging Findings of Acute Intermittent Porphyria Patients

Two Novel Hydroxymethylbilane Synthase Splicing Mutations Predispose to Acute Intermittent Porphyria.

Acute intermittent porphyria (AIP) is an autosomal dominant genetic disease caused by a lack or decrease in hydroxymethylbilane synthase (HMBS) activity. It is characterized by acute nerve and visceral attacks caused by factors in the process of heme synthesis. The penetrance rate of this disease is low, and the heterogeneity is strong. Here, we reported two novel HMBS mutations from two unrelated Chinese AIP patients and confirmed the pathogenicity of these two mutations. We found the HMBS c.760–771+2delCTGAGGCACCTGGTinsGCTGCATCGCTGAA and HMBS c.88-1G>C mutations by second-generation sequencing and Sanger sequencing. The in vitro expression analysis showed that these mutations caused abnormal HMBS mRNA splicing and premature termination or partial missing of HMBS protein. Homologous modeling analysis showed that the HMBS mutants lacked the amino acids which are crucial for the enzyme activity or the protein stability. Consistently, enzyme activity analysis confirmed that the HMBS mutants’ overexpression cells exhibited the reduced enzyme activity compared with the HMBS wildtype overexpression cells. Our study identified and confirmed two novel pathogenic HMBS mutations which will expand the molecular heterogeneity of AIP and provide further scientific basis for the clinical diagnosis of AIP.

Profiling of Serum Metabolites of Acute Intermittent Porphyria and Asymptomatic HMBS Mutation Carriers.

This study aims to present the serum metabolite profiles of patients with acute intermittent porphyria (AIP) and identify specific metabolites that could potentially discriminate between AIP, asymptomatic HMBS mutation carriers, and healthy individuals. The study cohort included 46 female participants: 21 AIP patients, 5 asymptomatic carriers, and 20 ‘normal’ participants (without HMBS gene mutation). Serum samples were analyzed for 157 selected metabolites or clinical variables using an assay combining liquid chromatography MS/MS and direct flow injection. AUC analysis was used to distinguish unique variables between the three groups. A total of 15 variables differed significantly between the AIP and normal control group (VIP score > 1.0 and p < 0.05 with FDR correction). In AIP patients, the levels tyrosine, valine, and eGFR were significantly lower, and the levels of sphingomyelin C16:0, C24:0, C24:1, phosphatidylcholine diacyl C32:1, C36:1, C36:3, ornithine, sarcosine, citrulline, blood urea nitrogen AST, and ALT were significantly higher. The AUC of these 15 variables in discriminating between normal and AIP patients ranged between 0.73 and 0.94 (p < 0.05). In conclusion, serum metabolic profiles differ between normal individuals and patients carrying the HMBS mutation. The unique metabolites associated with AIP identified in this study may be useful for monitoring the development of AIP symptoms.

Identification and molecular analysis of 17 novel variants of hydroxymethylbilane synthase in Chinese patients with acute intermittent porphyria.

A partial deficiency of the heme biosynthetic enzyme hydroxymethylbilane synthase (HMBS) leads to acute intermittent porphyria (AIP), a severe neurovisceral, autosomal dominant disorder with low penetrance. Even though in-depth investigations of the HMBS variants have been carried out by researchers in Britain, France, Russia, and Sweden, this area remains uninvestigated in China owing to the rarity and lack of clinical understanding of the disease. In this study, 78 unrelated AIP patients revealed 48 different HMBS variants, of which 17 were novel. These included 22 missense variants, 9 splicings, 5 nonsense variants, 10 small deletions, 1 repeat insertion, and 1 complex deletion-insertion variant. The variant c.673C > T, found in 10 unrelated patients, was the most frequent variant, followed by the variant c.517C > T, found in 7 unrelated patients. We performed western blotting and immunofluorescence staining with four novel variants (c.653G > A, c.597dupC, c.726-727del, and c.1045_1046delAA) to detect the expression levels of mutant HMBSs. The results showed a variant-mediated decrease in the mutant-HMBS level, suggesting that the variant resulted in impaired gene product functions. Moreover, the in vitro functional verification in this study provided PS3_moderate evidence for American College of Medical Genetics and Genomics (ACMG) to grade the pathogenicity of novel variants in AIP.

Dysregulation of homocysteine homeostasis in acute intermittent porphyria patients receiving heme arginate or givosiran.

Acute intermittent porphyria (AIP) is a rare metabolic disease caused by mutations within the hydroxymethylbilane synthase gene. Previous studies have reported increased levels of plasma total homocysteine (tHcy) in symptomatic AIP patients. In this study, we present long-term data for tHcy and related parameters for an AIP patient cohort (n=37) in different clinical disease-states. In total, 25 patients (68%) presented with hyperhomocysteinemia (HHcy; tHcy > 15 μmol/L) during the observation period. HHcy was more frequent in AIP patients with recurrent disease receiving heme arginate, than in nonrecurrent (median tHcy: 21.6μmol/L; range: 10-129 vs median tHcy: 14.5μmol/L; range 6-77). Long-term serial analyses showed a high within-person tHcy variation, especially among the recurrent patients (coefficient of variation: 16.4%-78.8%). HHcy was frequently associated with low blood concentrations of pyridoxal-5'-phosphate and folate, while cobalamin concentration and the allele distribution of the methylene-tetrahydrofolate-reductase gene were normal. Strikingly, 6 out of the 9 recurrent patients who were later included in a regime of givosiran, a small-interfering RNA that effectively reduced recurrent attacks, showed further increased tHcy (median tHcy in 9 patients: 105 μmol/L; range 16-212). Screening of amino acids in plasma by liquid-chromatography showed co-increased levels of methionine (median 71 μmol/L; range 23-616; normal <40), suggestive of acquired deficiency of cystathionine-β-synthase. The kynunerine/tryptophan ratio in plasma was, however, normal, indicating a regular metabolism of tryptophan by heme-dependent enzymes. In conclusion, even if HHcy was observed in AIP patients receiving heme arginate, givosiran induced an aggravation of the dysregulation, causing a co-increase of tHcy and methionine resembling classic homocystinuria.

Cost savings with hemin versus givosiran for the treatment of patients with acute intermittent porphyria (AIP)

Objective Since 1983, hemin has been FDA-approved for acute intermittent porphyria (AIP) attacks. In 2019, FDA approved givosiran for the treatment of adults with acute hepatic porphyria. The objective of this research was to estimate and compare the total cost of AIP-related healthcare for patients treated with hemin or givosiran. Methods A microsimulation cost model was developed to estimate the annual economic impact of hemin versus givosiran treatment for patients with AIP from the U.S. healthcare payer perspective. Hemin treatment costs were calculated from the Hemin Shipment Data in which patients were defined as receiving acute attack treatment or prophylaxis treatment based on shipment patterns. Three separate hemin subpopulations were considered: one attack per year, multiple attacks per year, and hemin prophylaxis. Treatment costs for givosiran (with hemin for acute attacks) were simulated based on Phase III trial efficacy results applied to individual treatment histories in the Hemin Shipment Data. Other healthcare utilization was also considered. Outcomes were annualized and expenditures inflated to 2019. Results For all patients with AIP, the average annual total cost of care with hemin was 78% lower (difference = $482,113; 95% CI=$373,638–$594,778) than the average annual total cost of care with givosiran. Average annual total cost of care with hemin was between 46% and 92% lower than givosiran for the three hemin subpopulations: one attack per year (difference = $545,219; 95% CI=$436,584–$657,239), multiple attacks per year (difference = $459,366; 95% CI=$350,291–$574,403), and hemin prophylaxis (difference = $311,950; 95% CI=$191,898–$435,893). Cost savings with hemin were robust to one-way and probabilistic sensitivity as well as scenario analyses. Conclusions Hemin is expected to provide cost savings compared to givosiran for all AIP patients and subpopulations. Lower annual total costs of care with hemin range from $311,950 to $545,219 less depending on whether the patient uses hemin prophylactically or for acute treatment attacks.

Brain ventricular enlargement in human and murine acute intermittent porphyria.

The morphological changes that occur in the central nervous system of patients with severe acute intermittent porphyria (AIP) have not yet been clearly established. The aim of this work was to analyze brain involvement in patients with severe AIP without epileptic seizures or clinical posterior reversible encephalopathy syndrome, as well as in a mouse model receiving or not liver-directed gene therapy aimed at correcting the metabolic disorder. We conducted neuroradiologic studies in 8 severely affected patients (6 women) and 16 gender- and age-matched controls. Seven patients showed significant enlargement of the cerebral ventricles and decreased brain perfusion was observed during the acute attack in two patients in whom perfusion imaging data were acquired. AIP mice exhibited reduced cerebral blood flow and developed chronic dilatation of the cerebral ventricles even in the presence of slightly increased porphyrin precursors. While repeated phenobarbital-induced attacks exacerbated ventricular dilation in AIP mice, correction of the metabolic defect using liver-directed gene therapy restored brain perfusion and afforded protection against ventricular enlargement. Histological studies revealed no signs of neuronal loss but a denser neurofilament pattern in the periventricular areas, suggesting compression probably caused by imbalance in cerebrospinal fluid dynamics. In conclusion, severely affected AIP patients exhibit cerebral ventricular enlargement. Liver-directed gene therapy protected against the morphological consequences of the disease seen in the brain of AIP mice. The observational study was registered at Clinicaltrial.gov as NCT02076763.

The clinical importance of early acute hepatic porphyria diagnosis: a national cohort.

Acute hepatic porphyria (AHP) attacks begin with abdominal pain and can progress to severe life-threatening conditions. Early diagnosis and treatment may prevent these complications. We investigated the difference between the severity of porphyria attacks before and after porphyria diagnosis. A retrospective study including AHP patients hospitalized for an acute attack in Israel during a 15-year period. Diagnosis of an attack was based on typical clinical symptoms accompanied by at least one documented elevated urinary porphobilinogen above fourfold of normal values. The primary outcome was intensive care unit (ICU) admissions. Secondary outcomes included the length of hospital stay, severe hyponatremia, seizures, and psychiatric symptoms. 42 attacks in 9 patients were included. Most attacks occurred in women (78.6%) and in acute intermittent porphyria patients (76.2%). The mean age of attack was 26.5 (± 6.3) years. Attacks following porphyria diagnosis had a lower prevalence of ICU admission (3.3% versus 75.0%, p < 0.001), seizures (0% versus 50.0%, p < 0.001), psychiatric symptoms (23.3% versus 66.7%, p = 0.01), severe hyponatremia (16.7% versus 83.3%, p < 0.001), and median length of hospital stay (5 versus 11.0days, p < 0.001). These results remained significant after simple univariate logistic regression for ICU admission [odds ratio (OR) 0.01, 95% confidence interval (CI) 0.00-0.12], prolonged hospital stay (OR 0.08, 95% CI 0.01-0.41), seizures or neurological symptoms (OR 0.06, 95% CI 0.01-0.30), and severe hyponatremia (OR 0.02, 95% CI 0.00-0.20). Previously diagnosed AHP patients have a significantly milder attack course as compared to previously undiagnosed patients. Family screening following sentinel cases might prevent severe AHP attacks.