A 9-year-old girl with blisters on the hands and face: An early presentation of variegate porphyria.

Variegate porphyria (VP) is a rare subtype of porphyrias characterized by dysfunction of enzymes in the heme biosynthesis pathway leading to an accumulation of porphyrins and their precursors. The resulting buildup can manifest as neuropsychiatric symptoms and photosensitive blistering eruptions on sun-exposed skin. We report a case of VP in a 9-year-old girl with many confounding medical factors that warranted alternative explanations for her cutaneous lesions. VP has been reported infrequently in the pediatric population and is associated with more severe neuropsychiatric outcomes compared to adult-onset disease.

Effects of Supplemental Drugs on Hexaminolevulinate (HAL)-Induced PpIX Fluorescence in Bladder Cancer Cell Suspensions.

Seven different inhibitors of the heme metabolic pathway were applied in combination with HAL to study the formation of PpIX in bladder cancer HT1197 and normal fibroblast HFFF2 cells ex vivo, specifically with the aim to increase the fluorescence contrast between cancer and non-cancer cells. The mRNA expression of enzymes involved in the heme biosynthesis pathway were measured via PCR following incubation with the drugs in order to link the fluorescence levels and metabolic activity. The exogenous administration of HAL does lead to cancer-specific PpIX accumulation. However, the contrast between cancer and normal cells in suspension was not enhanced by the enzyme inhibitors and iron-chelating agents tested, nor did the mRNA expression necessarily correlate with the fluorescence intensity. The results indicate that a difference in the metabolic activity of cells in suspension may limit the applicability of exogenous enzyme inhibitor administration as a mean to improve the fluorescence-based detection of cancer cells shed in body fluids.

Acute hepatic porphyrias: Identification of 46 hydroxymethylbilane synthase, 11 coproporphyrinogen oxidase, and 20 protoporphyrinogen oxidase novel mutations.

The acute hepatic porphyrias (AHPs) are inborn errors of heme biosynthesis, which include three autosomal dominant porphyrias, Acute Intermittent Porphyria (AIP), Hereditary Coproporphyria (HCP), and Variegate Porphyria (VP), and the ultra-rare autosomal recessive porphyria, δ-Aminolevulinic Acid Dehydratase Deficiency Porphyria (ADP). AIP, HCP, VP, and ADP each results from loss-of-function (LOF) mutations in their disease-causing genes: hydroxymethylbilane synthase (HMBS); coproporphyrinogen oxidase (CPOX); protoporphyrinogen oxidase (PPOX), and δ-aminolevulinic acid dehydratase (ALAD), respectively. During the 11-year period from January 1, 2007 through December 31, 2017, the Mount Sinai Porphyrias Diagnostic Laboratory diagnosed 315 unrelated AIP individuals with HMBS mutations, including 46 previously unreported mutations, 29 unrelated HCP individuals with CPOX mutations, including 11 previously unreported mutations, and 54 unrelated VP individuals with PPOX mutations, including 20 previously unreported mutations. Overall, of the 1692 unrelated individuals referred for AHP molecular diagnostic testing, 398 (23.5%) had an AHP mutation. Of the 650 family members of mutation-positive individuals tested for an autosomal dominant AHP, 304 (46.8%) had their respective family mutation. These data expand the molecular genetic heterogeneity of the AHPs and document the usefulness of molecular testing to confirm the positive biochemical findings in symptomatic patients and identify at-risk asymptomatic family members.

Hybrid Zinc Phthalocyanine/PVDF-HFP System for Reducing Biofouling in Water Desalination: DFT Theoretical and MolDock Investigations.

Fouling and biofouling remain significant challenges in seawater desalination plants. One practical approach to address these issues is to develop anti-biofouling membranes. Therefore, novel hybrid zinc phthalocyanine/polyvinylidene fluoride-co-hexafluoropropylene (Zn(4-PPOx)4Pc/PVDF-HFP) membranes were prepared by electrospinning to evaluate their properties against biofouling. The hybrid nanofiber membrane was characterized by atomic force microscopy (AFM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and contact angle measurements. The theoretical calculations of PVDF-HFP, Zn(4-PPOx)4Pc), and Zn(4-PPOx)4Pc/PVDF-HFP nanofibers were performed using a hybrid functional RB3LYP and the 6-31 G (d,p) basis set, employing Gaussian 09. DFT calculations illustrated that the calculated physical and electronic parameters ensured the feasibility of the interaction of PVDF-HFP with Zn(4-PPOx)4Pc via a halogen-hydrogen bond, resulting in a highly stable and remarkably reactive structure. Moreover, molecular electrostatic potential (MEP) maps were drawn to identify the reactive regions of the Zn(4-PPOx)4Pc and PVDF-HFP/Zn(4-PPOx)4Pc nanofibers. Molecular docking analysis revealed that Zn(4-PPOx)4Pc has highest binding affinity (-8.56 kcal/mol) with protein from S. aureus (1N67) mainly with ten amino acids (ASP405, LYS374, GLU446, ASN406, ALA441, TYR372, LYS371, TYR448, LYS374, and ALA442). These findings highlight the promising potential of Zn(4-PPOx) 4Pc/PVDF-HFP nanocomposite membranes in improving the efficiency of water desalination by reducing biofouling and providing antibacterial properties.

Further Characterization of the Neuroendocrine Phenotype Associated With the PPOX-Related Variegate Porphyria.

BACKGROUND: Variegate porphyria is caused by mutations in the PPOX gene; it usually presents in adolescents and adults as an autosomal dominant condition, with cutaneous features or acute peripheral and/or central nervous system crises. A rarer variant, homozygous variegate porphyria, presents in childhood with cutaneous manifestations as well as neurophenotypes. This study sought to further characterize the homozygous PPOX-related neuroendocrine phenotype. METHODS: This study is a retrospective review of the patients' charts, including their clinical evaluation and molecular genetics, neurodiagnostic, and neuroradiological investigations. RESULTS: We describe here three children from a consanguineous family who presented with nystagmus, developmental delay and ataxia, photosensitive skin manifestations, and adrenal insufficiency. Analysis of porphyrins in plasma, urine, and stool together with a genetic study of the PPOX gene confirmed the diagnosis. Interestingly, brain MRI showed severe hypomyelination, a finding rarely reported in variegate porphyria, together with adrenal insufficiency. CONCLUSION: We recommend analysis of porphyrins in unexplained hypomyelination disorders. Patients with variegate porphyria should be tested for adrenal insufficiency.

Case Report: Variegate porphyria disclosed by post-gastric bypass complications and causing predominant painful sensorimotor axonal peripheral neuropathy.

Background and aims: Porphyrias constitute a group of rare genetic diseases due to various, mostly autosomal dominant mutations, causing enzymatic deficiency in heme biosynthesis. As a result, neurotoxic porphyrin precursors and light-sensitive porphyrins accumulate, while dysfunction in their targets determines the disease symptoms. Variegate porphyria (VP), one of the acute hepatic porphyrias, is caused by a protoporphyrinogen oxidase (PPOX) mutation. During acute attacks, among other factors, triggered by drugs, stressors, or fasting, an increase in urinary and fecal porphobilinogen (PBG), aminolevulinic acid (ALA), and porphyrins occurs, damaging the autonomous, peripheral, or central nervous system. The disease remains often latent or displays minimal symptoms usually overlooked, exposing undiagnosed patients to potentially serious complications in the presence of the aforementioned triggers. Case report: This 46-year-old woman presented, some days after a bariatric surgery, with severe flaccid tetraparesis and neuropathic pain, initially misdiagnosed as a functional neurological disorder. The severe axonal sensorimotor polyneuropathy led to further investigations, disclosing high urinary porphobilinogen, ALA, and porphyrin levels due to a new PPOX mutation. Retrospectively, it appeared that the patient had had typical VP symptoms (abdominal pain, fragile skin, and dark urine episodes) for years prior to the surgery. Treated with carbohydrate load, neurorehabilitation, and analgesics, she slowly recovered to full mobility, with partial autonomy in her daily life activities, although fatigue and severe pain persisted, preventing her from returning to work. Conclusion: This case documents gastric bypass surgery as a trigger of severe VP invalidating neurological symptoms and illustrates how the delayed diagnosis and post-interventional complications could have been prevented by screening for porphyria cardinal symptoms prior to the intervention. Likewise, this cost-effective screening should be performed before any treatment influencing the diet, which would dramatically improve the porphyria diagnosis rate and outcome.

A boy with blistering of sun-exposed skin and finger shortening: the first case of Variegate Porphyria with a novel mutation in protoporphyrinogen oxidase (PPOX) gene in Iran: a case report and literature review.

Variegate Porphyria (VP) is an inherited rare disorder that is caused by mutations in the protoporphyrinogen oxidase (PPOX) gene. This deficiency is associated with the accumulation of porphyrins and porphyrin precursors in the body, which, in turn, can potentially result in a variety of skin and neurological symptoms. Here, we reported a 7-year-old boy with homozygous VP and novel mutation on PPOX gene. He was admitted with three episodes of generalized tonic-clonic seizure in the last 6 months. He was presented with lesions, hyperpigmentation, fragility, and blistering of sun-exposed skin. The weakness of limbs and brachydactyly were observed. In the follow-up, he had aggressive behavior, learning disability and abdominal pain, particularly around the navel. Eventually, the whole exome sequencing (WES) result reported a novel homozygous pathogenic variant (c.1072G > A p.G358R) in PPOX gene which confirmed the VP. He had been advised to be away from the sun and use sunscreen regularly.

Novel PPOX exonic mutation inducing aberrant splicing in a patient with homozygous variegate porphyria.

INTRODUCTION: Variegate porphyria (VP; OMIM 176200) is one of the acute hepatic porphyrias, and it is characterized by the partial deficiency of protoporphyrinogen oxidase (PPOX). The unusual homozygous variant with mutations on both alleles of PPOX is distinguished with general heterozygous VP by several typical points such as severe defect in PPOX enzyme activity, early onset of photosensitivity before puberty, and skeletal deformity. MATERIAL AND METHOD: In this study, we describe a very rare case of autosomal recessive form of true homozygous VP found in a Chinese patient with consanguineous parents. Sanger sequencing of the PPOX gene showed a novel homozygous variant located at the first base of exon 8 of the gene, i.e., NM_000309.3c.808G > T. To investigate aberrant splicing induced by the mutant, wild-type exon 8 and mutant exon 8 were expressed in pET01 vector as minigene in cultured-cells and analyzed by RT-PCR. RESULTS: The wildtype PPOX showed an expected band in the gel electrophoresis after RT-PCR. The PPOX c.808G > T only showed a band similar to the band size of the vector only control. This result suggested c.808G > T mutant is an exonic mutation inducing aberrant splicing of pre-mRNA of the PPOX gene. CONCLUSION: This study showed a very rare case of homozygous VP with autosomal recessive homoallelic pattern. In comparison with previous cases of homozygous VP presenting brachydactyly, it is notable that our patient did not have any skeletal deformities.

Butafenacil: A positive control for identifying anemia- and variegate porphyria-inducing chemicals.

Butafenacil is an herbicide that inhibits protoporphyrinogen oxidase (PPOX), an enzyme that catalyzes oxidation of protoporphyrinogen IX to protoporphyrin IX during chlorophyll and heme biosynthesis. Based on a high-content screen, we previously identified butafenacil as a potent inducer of anemia in zebrafish embryos. Therefore, the objective of this study was to begin investigating the utility of butafenacil as a positive control for identifying anemia- and variegate porphyria-inducing chemicals. Static exposure to butafenacil from 5 to 72 h post-fertilization (hpf) in glass beakers resulted in a concentration-dependent decrease in arterial circulation at low micromolar concentrations. At 72 hpf, the magnitude of butafenacil-induced anemia was similar when embryos were exposed in the presence or absence of light, whereas protoporphyrin accumulation and acute toxicity were significantly lower or absent when embryos were exposed under dark conditions. To identify sensitive developmental windows, we treated embryos to butafenacil from 5, 10, 24, or 48 hpf to 72 hpf in the presence of light, and found that anemia and protoporphyrin accumulation were present at 72 hpf following initiation of exposure at 5 and 10 hpf. On the contrary, protoporphyrin accumulation - but not anemia - was present following initiation of exposure at 24 hpf. Lastly, protoporphyrin accumulation at 72 hpf after exposure from 24 to 48 hpf suggests that protoporphyrin was not eliminated over a 24-h recovery period. Collectively, our data suggests that butafenacil may be a reliable positive control for identifying anemia- and variegate porphyria-inducing chemicals.

Characterisation of the flavin adenine dinucleotide binding region of Myxococcus xanthus protoporphyrinogen oxidase.

Protoporphyrinogen oxidase (PPOX), the penultimate enzyme in the haem biosynthetic pathway catalysers the six electron oxidation of protoporphyrinogen-IX to protoporphyrin-IX, in the presence of flavin adenine dinucleotide (FAD) and oxygen. In humans, partial defects in PPOX result in variegate porphyria. In this study, the FAD binding region in Myxococcus xanthus PPOX was analysed by engineering and characterising a selection of mutant proteins. Amino acid residues which interact with FAD via their side chains were selected for study. Mutants were characterised and compared with wild type protein. Characterisation included FAD quantitation, analysis of FAD spectra and kinetic assay. Results revealed that Serine 20 mutants could still bind FAD, but polarity in this position is favourable, yet not essential for the integrity of FAD binding. Study of Glutamate 39 mutants suggest that a negative charge at position 39 is clearly favoured for interaction with the ribose ring of FAD, as all non-conservative replacements could not bind sufficient FAD. Asparagine 441 appears not to be directly involved in FAD binding but rather in stabilizing the FAD, and polarity in this position appears important. Tryptophan 408 may play a role in orientating or stabilizing the bound substrate during catalysis, and a non-polar (or slightly polar) residue is favoured at this position; however, aromaticity in this position appears not to be critical. Overall this study sheds further light on how M. xanthus PPOX interacts with FAD.