Associations among behavior-related susceptibility factors in porphyria cutanea tarda

Understanding Coproporphyrins and their Disposition: Coproporphyrinuria is Common, of Diverse Cause, and Rarely Indicates Porphyria

Coproporphyrins [CPs] are often mildly increased in plasma and urine, which leads to erroneous over-diagnosis of porphyrias. Herein we provide an overview of normal CP metabolism and factors that influence its disposition. We reviewed extant literature and here summarize and put into context current knowledge of CP metabolism and its disposition. CPs are formed as byproducts of normal heme synthesis. Normally they are removed chiefly by hepatocytes into bile and then stool. Organic anion transporting peptides [OATPs] and multidrug resistance-associated proteins [MRPs] facilitate the uptake of CPs into epithelial cells and removal. Xenobiotics inhibit the activities of MRPs and/or OATPs and affect the metabolism and disposition of CPs. CP concentrations are used as endogenous probes for assessing altered functions of OATPs. Diverse liver diseases and disorders lead to decreased secretion of CPs into bile and thus to increased concentrations of CPs in plasma and urine. Usually, mild to moderate increases in urinary CPs are due to alcohol, heavy metals, drug effects on transporters, or non-porphyric liver diseases not to porphyrias or to other inherited syndromes.

Practical recommendations for biochemical and genetic diagnosis of the porphyrias

The porphyrias are a group of rare inborn errors of metabolism associated with various clinical presentations and long-term complications, making them relevant differential diagnoses to consider for many clinical specialities, especially hepatologists, gastroenterologists and dermatologists. To diagnose a patient with porphyria requires appropriate biochemical investigations, as clinical features alone are not specific enough. Furthermore, it is important to be aware that abnormalities of porphyrin accumulation and excretion occur in many other disorders that are collectively far more common than the porphyrias. In this review, we provide an overview of porphyria-related tests with their strengths and limitations, give recommendations on requesting and diagnostic approaches in non-expert and expert laboratories for different clinical scenarios and discuss the role of genetic testing in the porphyrias. To diagnose porphyria in a currently symptomatic patient requires analysis of biochemical markers to demonstrate typical patterns of haem precursors in urine, faeces and blood. The use of genomic sequencing in diagnostic pathways for porphyrias requires careful consideration, and the demonstration of increased porphyrin-related markers is necessary prior to genomic testing in symptomatic patients. In the acute porphyrias, genomic testing is presently a useful adjunct for genetic counselling of asymptomatic family members and the most common cutaneous porphyria, porphyria cutanea tarda, is usually a sporadic, non-hereditary disease. Getting a correct and timely porphyria diagnosis is essential for delivering appropriate care and ensuring best patient outcome.

Update on the Porphyrias

The porphyrias are a group of rare diseases, each resulting from a defect in a different enzymatic step of the heme biosynthetic pathway. They can be broadly divided into two categories, hepatic and erythropoietic porphyrias, depending on the primary site of accumulation of heme intermediates. These disorders are multisystemic with variable symptoms that can be encountered by physicians in any specialty. Here, we review the porphyrias and describe their clinical presentation, diagnosis, and management. We discuss novel therapies that are approved or in development. Early diagnosis is key for the appropriate management and prevention of long-term complications in these rare disorders.

Burden, Outcome, and Comorbidities of Extrahepatic Manifestations in Hepatitis C Virus Infection

Hepatitis C virus (HCV) is a significant cause of chronic liver diseases worldwide and is associated with negative consequences, including cirrhosis, hepatic decompensation, hepatocellular carcinoma, and increased risk of mortality. In addition to liver-related morbidities, HCV is also associated with several extrahepatic manifestations, including mixed cryoglobulinemia, diabetes mellitus, cardiocerebrovascular disease, lymphoma, and autoimmune diseases. These non-liver-related complications of HCV increase the complexity of this disease and can contribute to the economic burden, morbidity, quality of life, and mortality throughout the world. Therefore, understanding how this virus can contribute to each extrahepatic manifestation is worth investigating. Currently, the advancement of HCV treatment with the advent of direct-acting anti-viral agents (DAAs) has led to a high cure rate as a result of sustained virologic response and tremendously reduced the burden of extrahepatic complications. However, HCV-associated extrahepatic manifestations remain a relevant concern, and this review aims to give an updated highlight of the prevalence, risk factors, associated burdens, and treatment options for these conditions.

Role of ABCB1 and glutathione S-transferase gene variants in the association of porphyria cutanea tarda and human immunodeficiency virus infection

In Argentina, porphyria cutanea tarda (PCT) is strongly associated with infection with human immunodeficiency virus (HIV); however, whether the onset of this disease is associated with HIV infection and/or the antiretroviral therapy has not been determined. The ABCB1 gene variants c.1236C>T, c.2677G>T/A and c.3435C>T affect drug efflux. The GSTT1 null, GSTM1 null and GSTP1 (c.313A>G) gene variants alter Glutathione S-transferase (GST) activity, modifying the levels of xenobiotics. The aim of the present study was to evaluate the role of genetic variants in initiation of PCT and to analyze the genetic basis of the PCT-HIV association. Control individuals, and HIV, PCT and PCT-HIV patients were recruited, PCR-restriction fragment length polymorphism was used to genotype the ABCB1 and GSTP1 variants, and multiplex PCR was used to study the GSTM1 and GSTT1 variants. The high frequency of c.3435C>T (PCT and PCT-HIV) and c.1236C>T (PCT) suggested that the onset of PCT were not specifically related to HIV infection or antiretroviral therapy for these variants. c.2677G>T/A frequencies in the PCT-HIV patients were higher compared with the other groups, suggesting that a mechanism involving antiretroviral therapy served a role in this association. PCT-HIV patients also had a high frequency of GSTT1 null and low frequency for GSTM1 null variants; thus, the genetic basis for PCT onset may involve a combination between the absence of GSTT1 and the presence of GSTM1. In conclusion, genes encoding for proteins involved in the flow and metabolism of xenobiotics may influence the PCT-HIV association. The present study is the first to investigate the possible role of GST and ABCB1 gene variants in the triggering of PCT in HIV-infected individuals, to the best of our knowledge, and may provide novel insights into the molecular basis of the association between PCT and HIV.

Porphyria cutanea tarda: Recent update

Porphyria cutanea tarda (PCT) is the most common human porphyria, due to hepatic deficiency of uroporphyrinogen decarboxylase (UROD), which is acquired in the presence of iron overload and various susceptibility factors, such as alcohol abuse, smoking, hepatitis C virus (HCV) infection, HIV infection, iron overload with HFE gene mutations, use of estrogens, and UROD mutation. Patients with familial or type II PCT due to autosomal dominant UROD mutation also require other susceptibility factors, as the disease phenotype requires hepatic UROD deficiency to below 20% of normal. PCT clinically manifests with increased skin fragility and blistering skin lesions on sun exposed areas. The common age of presentation is 5th to 6th decade and occurs slightly more commonly in males. Although mild liver biochemical profile are common, advanced fibrosis and cirrhosis with hepatocellular carcinoma (HCC) can occasionally develop. Screening for HCC using ultrasound examination is recommended in PCT patients, especially with cirrhosis and advanced fibrosis. PCT is effectively and readily treatable with the use of either repeated phlebotomy or use of 100 mg hydroxychloroquine orally twice a week, and both the treatments are equally effective and safe. With the advent of new or direct antiviral agents for HCV infection, treatment of concomitant HCV has become safer and effective. Data are emerging on the benefit of these drugs as monotherapy for both PCT and HCV. After the achievement of remission of PCT, there remains a potential for relapse, especially when the susceptibility factors are not adequately controlled. Scanty data from retrospective and observational studies shows the relapse rate to be somewhat higher after remission with low-dose hydroxychloroquine as compared to phlebotomy induced remission. Future studies are needed on exploring mechanism of action of 4-aminoquinolines, understanding interaction of HCV and PCT, and relapse of PCT on long-term follow-up.

Heme biosynthesis and the porphyrias

Porphyrias, is a general term for a group of metabolic diseases that are genetic in nature. In each specific porphyria the activity of specific enzymes in the heme biosynthetic pathway is defective and leads to accumulation of pathway intermediates. Phenotypically, each disease leads to either neurologic and/or photocutaneous symptoms based on the metabolic intermediate that accumulates. In each porphyria the distinct patterns of these substances in plasma, erythrocytes, urine and feces are the basis for diagnostically defining the metabolic defect underlying the clinical observations. Porphyrias may also be classified as either erythropoietic or hepatic, depending on the principal site of accumulation of pathway intermediates. The erythropoietic porphyrias are congenital erythropoietic porphyria (CEP), and erythropoietic protoporphyria (EPP). The acute hepatic porphyrias include ALA dehydratase deficiency porphyria, acute intermittent porphyria (AIP), hereditary coproporphyria (HCP) and variegate porphyria (VP). Porphyria cutanea tarda (PCT) is the only porphyria that has both genetic and/or environmental factors that lead to reduced activity of uroporphyrinogen decarboxylase in the liver. Each of the 8 enzymes in the heme biosynthetic pathway have been associated with a specific porphyria (Table 1). Mutations affecting the erythroid form of ALA synthase (ALAS2) are most commonly associated with X-linked sideroblastic anemia, however, gain-of-function mutations of ALAS2 have also been associated with a variant form of EPP. This overview does not describe the full clinical spectrum of the porphyrias, but is meant to be an overview of the biochemical steps that are required to make heme in both erythroid and non-erythroid cells.

Sporadic Porphyria Cutanea Tarda as the Initial Manifestation of Hereditary Hemochromatosis

Porphyria cutanea tarda (PCT) is a skin disorder characterized by abnormal heme synthesis. We present a 45-year-old man with intermittent skin lesions recurring annually for years. Skin biopsy and measurement of serum heme precursors confirmed a diagnosis of PCT. He had persistently elevated alanine and aspartate transferase. He was referred to hematology and had genetic testing with iron studies which also revealed hereditary hemochromatosis (HH). Therapeutic phlebotomy was initiated, which led to resolution of iron overload and skin lesions. We highlight the associated conditions of PCT and HH, their common therapy of phlebotomy, and initial manifestations of HH.

The rash in life-threatening metabolic and endocrine disorders

Recognizing the skin manifestations of metabolic and endocrine disorders, many of which may have potentially lethal complications, is important for dermatologists and other clinicians. The skin can be a window into a patient's internal health, and cutaneous manifestations can facilitate early diagnosis and intervention of potentially life-altering systemic disorders with associated morbidity and mortality. This contribution provides an overview of the diverse rashes associated with potentially lethal, acquired metabolic and endocrine disorders of the pituitary, thyroid, parathyroid, pancreas, adrenals, and blood, as well as neuroendocrine and nutritional disease.

Experience in management of porphyria cutanea tarda in a tertiary referral Brazilian hospital from 2002 to 2017

BACKGROUND

Porphyria cutanea tarda (PCT) is the most common porphyria worldwide. The known acquired precipitating factors that induce PCT include alcoholism, hepatitis C virus infection, human immunodeficiency virus infection, and estrogen intake. Hereditary hemochromatosis is considered an inherited risk factor. The aim of this study was to describe and analyze precipitating factors and family history, with emphasis on PCT management.

METHODS

A retrospective study of 87 patients with PCT was conducted between January 2002 and December 2017.

RESULTS

A male predominance of 1.8 : 1 was found. The median age at diagnosis was 49 years (range 18-71). Family history of PCT was observed in 19.5% of patients. Two or more acquired precipitating factors were present in 42.5%. Patients were treated with antimalarial monotherapy (72.4%), antimalarial combined with phlebotomy (22.9%), and only with phlebotomy (4.6%). Acquired precipitating factors and inherited factors were not associated with treatment group. There was a difference in 24 h-UP normalization rate between treatment groups; combined therapy takes longer than antimalarial monotherapy, 38 months versus 15 months, respectively (CI 95%, 6.5-63.5 vs. 12.9-17) (log-rank test, P = 0.004).

CONCLUSION

Precipitating factors did not seem to be associated with treatment choice; however, all acquired and inherited precipitating factors should be investigated, and the choice between phlebotomy and/or antimalarials should be individualized. All dermatologists treating PCT patients should observe transferrin saturation and ferritin levels to search for underlying hereditary hemochromatosis.

Porphyria Cutanea Tarda Presenting with Scleroderma, Ichthyosis, Alopecia, and Vitiligo

Porphyria cutanea tarda (PCT) is a cutaneous porphyria that presents later in life with cutaneous findings in sun-exposed sites. We report a complex case of PCT in a 67-year-old woman with an unusual constellation of cutaneous findings: scleroderma, acquired ichthyosis, and nonscarring alopecia. Possible triggers for her PCT include tamoxifen treatment for breast cancer and carrier status of the hemochromatosis gene. High-dose chloroquine was used to successfully achieve clinical remission and normalize her uroporphyrins. While on chloroquine she developed extensive classic vitiligo. It is not clear if this is another feature of her complex and unusual PCT, or a consequence of her antimalarial therapy.

Hepatitis C virus core protein triggers abnormal porphyrin metabolism in human hepatocellular carcinoma cells

Porphyria cutanea tarda (PCT), the most common of the human porphyrias, arises from a deficiency of uroporphyrinogen decarboxylase. Studies have shown a high prevalence of hepatitis C virus (HCV) infection in patients with PCT. While these observations implicate HCV infection as a risk factor for PCT pathogenesis, the mechanism of interaction between the virus and porphyrin metabolism is unknown. This study aimed to assess the effect of HCV core protein on intracellular porphyrin metabolism to elucidate the link between HCV infection and PCT. The accumulation and excretion of porphyrins after treatment with 5-aminolevulinic acid, a porphyrin precursor, were compared between cells stably expressing HCV core protein and controls. Cells expressing HCV core protein had lower amounts of intracellular protoporphyrin IX and heme and had higher amounts of excreted coproporphyrin III, the oxidized form of coproporphyrinogen III, compared with controls. These observations suggest that HCV core protein affects porphyrin metabolism and facilitates the export of excess coproporphyrinogen III and/or coproporphyrin III, possibly via porphyrin transporters. Real-time PCR analysis revealed that the presence of HCV core protein increased the mRNA expression of porphyrin exporters ABCG2 and FLVCR1. Western blot analysis showed a higher expression level of FLVCR1, but not ABCG2, as well as a higher expression level of mature ALAS1, which is the rate-limiting enzyme in the heme synthesis pathway, in HCV core protein-expressing cells compared with controls. The data indicate that HCV core protein induced abnormal intracellular porphyrin metabolism, with an over-excretion of coproporphyrin III. These findings may partially account for the susceptibility of HCV-infected individuals to PCT development.

Disappearance of multiple hyperechoic liver nodules in sporadic porphyria cutanea tarda after treatment with ledipasvir/sofosbuvir for hepatitis C

Ultrasonography in a 60-year-old man with chronic hepatitis C (CHC) demonstrated multiple hyperechoic nodules. Radiological investigations did not reveal any signs of malignancy. However, magnetic resonance chemical shift imaging showed multiple focal fatty changes in the liver. Urinary levels of uroporphyrin and coproporphyrin were elevated, and we made a diagnosis of porphyria cutanea tarda. Direct-acting antivirals, ledipasvir/sofosbuvir, were initiated for CHC, which led to sustained viral response, resolution of the liver nodules, and normalization of urinary porphyrin. Hepatitis C virus infection can cause porphyria cutanea tarda with multiple hyperechoic liver nodules, which might be cured by direct-acting antivirals.

Hepatitis C Treatment in Patients With Porphyria Cutanea Tarda

BACKGROUND

Hepatitis C virus (HCV) infection is a common susceptibility factor for porphyria cutanea tarda (PCT). Experience on HCV treatment in patients with PCT is limited. Recently, HCV treatment has improved with direct-acting antivirals (DAA). We review our experience on HCV treatment in patients with PCT with older and newer regimens.

MATERIALS AND METHODS

A retrospective chart review was conducted. HCV treatment was attempted 22 times in 13 patients with PCT (5 attempts in 1, 2 in 5 and 1 in the other 7 patients).

RESULTS

Before starting HCV treatment, PCT was in complete remission in 16, partial remission in 2, unknown status in 2 and active in 2 instances. PCT relapsed during therapy 6 times (all interferon-based regimens and 2 including telaprevir), 4 requiring treatment interruption. Treatment was interrupted for reasons other than PCT relapse in 2 patients treated with interferon-based regimens. To prevent PCT recurrence, hydroxychloroquine was continued during HCV therapy 6 times (3 interferon regimens, 2 ribavirin regimens without interferon and 1 DAA alone). Twelve patients achieved sustained viral response, 3 with interferon regimens and 9 with DAA. Two patients with active PCT were treated with DAA, with reduction of plasma porphyrins in 1 and normalization in the other at the end of HCV therapy.

CONCLUSIONS

HCV treatment regimens including interferon or ribavirin may precipitate PCT relapse. Hydroxychloroquine may be useful to prevent such relapses. In this limited experience, DAA were not associated with PCT relapse. Studies are needed to examine DAA as a primary PCT treatment in HCV-infected patients.

Hepatic porphyria: A narrative review

Porphyrias are a group of metabolic disorders, which result from a specific abnormality in one of the eight enzymes of the heme biosynthetic pathway. These have been subdivided based on the predominant site of enzyme defect into hepatic and erythropoietic types and based on clinical presentation into acute neurovisceral and cutaneous blistering porphyrias. This review focuses on hepatic porphyrias, which include acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), aminolevulinic acid dehydratase deficiency porphyria (ADP), and porphyria cutanea tarda (PCT). Of these, AIP and ADP are classified as acute porphyria, PCT as cutaneous, while VP and HCP present with both acute and cutaneous clinical manifestations. Porphobilinogen levels in a spot urine sample is the initial screening test for the diagnosis of acute hepatic porphyria, and plasma with spot urine porphyrin levels is the initial screening test to approach patients suspected of cutaneous porphyria. Specific biochemical porphyrin profile for each porphyria helps in determining the specific diagnosis. Pain relief and elimination of triggering agents are the initial steps in managing a patient presenting with an acute attack. Intravenous glucose administration terminates the mild episode of acute porphyria, with intravenous hemin needed for management of moderate to severe episodes. Liver transplantation is curative and may be needed for patients with a life-threatening acute porphyria attack or for patients with recurrent acute attacks refractory to prophylactic treatment. Of the cutaneous porphyrias, PCT is the most common and is frequently associated with a combination of multiple susceptibility factors such as alcohol use, smoking, hepatitis C virus infection, HIV infection, estrogen use, and mutations of the hemochromatosis gene. Regular phlebotomy schedule and low-dose hydroxychloroquine are effective and safe treatment options for management of PCT.

The D519G Polymorphism of Glyceronephosphate O-Acyltransferase Is a Risk Factor for Familial Porphyria Cutanea Tarda

Both familial and sporadic porphyria cutanea tarda (PCT) are iron dependent diseases. Symptoms of PCT resolve when iron stores are depleted by phlebotomy, and a sequence variant of HFE (C282Y, c.843G>A, rs1800562) that enhances iron aborption by reducing hepcidin expression is a risk factor for PCT. Recently, a polymorphic variant (D519G, c.1556A>G, rs11558492) of glyceronephosphate O-acyltransferase (GNPAT) was shown to be enriched in male patients with type I hereditary hemochromatosis (HFE C282Y homozygotes) who presented with a high iron phenotype, suggesting that GNPAT D519G, like HFE C282Y, is a modifier of iron homeostasis that favors iron absorption. To challenge this hypothesis, we investigated the frequency of GNPAT D519G in patients with both familial and sporadic PCT. Patients were screened for GNPAT D519G and allelic variants of HFE (both C282Y and H63D). Nucleotide sequencing of uroporphyrinogen decarboxylase (URO-D) identified mutant alleles. Patients with low erythrocyte URO-D activity or a damaging URO-D variant were classified as familial PCT (fPCT) and those with wild-type URO-D were classified as sporadic PCT (sPCT). GNPAT D519G was significantly enriched in the fPCT patient population (p = 0.0014) but not in the sPCT population (p = 0.4477). Both HFE C282Y and H63D (c.187C>G, rs1799945) were enriched in both PCT patient populations (p<0.0001) but showed no greater association with fPCT than with sPCT. Conclusion: GNPAT D519G is a risk factor for fPCT, but not for sPCT.

Porphyria Diagnostics-Part 1: A Brief Overview of the Porphyrias

Porphyria diseases are a group of metabolic disorders caused by abnormal functioning of heme biosynthesis enzymes and characterized by excessive accumulation and excretion of porphyrins and their precursors. Precisely which of these chemicals builds up depends on the type of porphyria. Porphyria is not a single disease but a group of nine disorders: acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), variegate porphyria (VP), δ-aminolevulinic acid dehydratase deficiency porphyria (ADP), porphyria cutanea tarda (PCT), hepatoerythropoietic porphyria (HEP), congenital erythropoietic porphyria (CEP), erythropoietic protoporphyria (EPP), and X-linked protoporphyria (XLP). Each porphyria results from overproduction of heme precursors secondary to partial deficiency or, in XLP, increased activity of one of the enzymes of heme biosynthesis. Taken together, all forms of porphyria afflict fewer than 200,000 people in the United States. Based on European studies, the most common porphyria, PCT, has a prevalence of 1 in 10,000, the most common acute porphyria, AlP, has a prevalence of ∼1 in 20,000, and the most common erythropoietic porphyria, EPP, is estimated at 1 in 50,000 to 75,000. CEP is extremely rare, with prevalence estimates of 1 in 1,000,000 or less. Only six cases of ADP are documented. The current porphyria literature is very exhaustive and a brief overview of porphyria diseases is essential in order for the reader to better appreciate the relevance of this area of research prior to undertaking biochemical diagnostics procedures. This unit summarizes the current knowledge on the classification, clinical features, etiology, pathogenesis, and genetics of porphyria diseases.

Sun, iron, alcohol and intrinsic liver disease: a recipe for failure

A 62-year-old Caucasian woman, with remote history of painful skin blistering and hypertrichosis, recent history of travel to Mexico and increased alcohol consumption, presented with progressively worsening jaundice and fatigue. Physical examination was remarkable for severe generalised jaundice, scleral icterus and erythematous facial blistering and scarring. Laboratory workup revealed markedly elevated total and direct bilirubin, mildly elevated transaminases, severe iron overload and increased urine coproporphyrin. Porphyria cutanea tarda was diagnosed, and she was treated with supportive measures including hydration and alcohol cessation. Pathology of her liver demonstrated mild iron overload and severe fatty infiltration. Hospital follow-up revealed complete resolution of jaundice and fatigue and near-normalisation of liver function tests.

HAART: a risk factor for development of porphyria cutanea tarda?

Porphyria cutanea tarda (PCT) is caused by inherited or acquired partial deficiency of the uroporphyrinogen-decarboxylase (Uro-D) enzyme activity. It is the most common form of porphyria. The main triggering factors to the development of porphyria cutanea tarda are alcohol, hepatitis C virus and human immunodeficiency virus. There are several reports of PCT associated with drugs, among them, antiretroviral therapy. We describe three HIV-positive patients, which showed photosensitivity as well as the emergence of tense blisters on sun-exposed areas during the use of highly active antiretroviral therapy (HAART) and discuss the possibility of PCT after the use of these drugs by those patients.

Low-dose hydroxychloroquine is as effective as phlebotomy in treatment of patients with porphyria cutanea tarda

BACKGROUND & AIMS

Porphyria cutanea tarda (PCT) is an iron-related disorder caused by reduced activity of hepatic uroporphyrinogen decarboxylase; it can be treated by phlebotomy or low doses of hydroxychloroquine. We performed a prospective pilot study to compare the efficacy and safety of these therapies.

METHODS

We analyzed data from 48 consecutive patients with well-documented PCT to characterize susceptibility factors; patients were treated with phlebotomy (450 mL, every 2 weeks until they had serum ferritin levels of 20 ng/mL) or low-dose hydroxychloroquine (100 mg orally, twice weekly, until at least 1 month after they had normal plasma levels of porphyrin). We compared the time required to achieve a normal plasma porphyrin concentration (remission, the primary outcome) for 17 patients treated with phlebotomy and 13 treated with hydroxychloroquine.

RESULTS

The time to remission was a median 6.9 months for patients who received phlebotomy and 6.1 months for patients treated with hydroxychloroquine treatment (6.7 and 6.5 mo for randomized patients), a difference that was not significant (log-rank, P = .06 and P = .95, respectively). The sample size was insufficient to confirm noninferiority of hydroxychloroquine treatment (hazard ratio, 2.19; 95% confidence interval, 0.95-5.06) for all patients. Patients who received hydroxychloroquine had substantially better compliance. There were no significant side effects of either treatment.

CONCLUSIONS

Hydroxychloroquine, 100 mg twice weekly, is as effective and safe as phlebotomy in patients with PCT, although noninferiority was not established. Given these results, higher-dose regimens of hydroxychloroquine, which have more side effects, do not seem justified. Compliance was better and projected costs were lower for hydroxychloroquine than phlebotomy treatment. Long-term studies are needed to compare durability of response. ClinicalTrials.gov number, NCT01573754.

Hepatitis C, porphyria cutanea tarda and liver iron: an update

Porphyria cutanea tarda (PCT) is the most common form of porphyria across the world. Unlike other forms of porphyria, which are inborn errors of metabolism, PCT is usually an acquired liver disease caused by exogenous factors, chief among which are excess alcohol intake, iron overload, chronic hepatitis C, oestrogen therapy and cigarette smoking. The pathogenesis of PCT is complex and varied, but hereditary or acquired factors that lead to hepatic iron loading and increased oxidative stress are of central importance. Iron loading is usually only mild or moderate in degree [less than that associated with full-blown haemochromatosis (HFE)] and is usually acquired and/or mutations in HFE. Among acquired factors are excessive alcohol intake and chronic hepatitis C infection, which, like mutations in HFE, decrease hepcidin production by hepatocytes. The decrease in hepcidin leads to increased iron absorption from the gut. In the liver, iron loading and increased oxidative stress leads to the formation of non-porphyrin inhibitor(s) of uroporphyrinogen decarboxylase and to oxidation of porphyrinogens to porphyrins. The treatment of choice of active PCT is iron reduction by phlebotomy and maintenance of a mildly iron-reduced state without anaemia. Low-dose antimalarials (cinchona alkaloids) are also useful as additional therapy or as alternative therapy for active PCT in those without haemochromatosis or chronic hepatitis C. In this review, we provide an update of PCT with special emphasis upon the important role often played by the hepatitis C virus.

Peripheral ulcerative keratitis and necrotizing scleritis initiated by trauma in the setting of mixed cryoglobulinemia

Purpose

To report a case of peripheral ulcerative keratitis and necrotizing scleritis precipitated by trauma in a patient with mixed cryoglobulinemia due to hepatitis C viral infection.

Methods

Case report and literature review.

Results

A 62-year-old man with a history of mixed cryoglobulinemia developed an episode of necrotizing scleritis and peripheral ulcerative keratitis one month after repair of a traumatic scleral defect with patch grafting. This episode resolved following treatment with high-dose corticosteroids and the patient underwent successful repeat patch grafting along with a free conjunctival autograft. This is the second reported case of necrotizing scleritis and peripheral ulcerative keratitis associated with mixed cryoglobulinemia.

Conclusion

Ophthalmologists should be aware of the association between mixed cryoglobulinemia and necrotizing scleritis/peripheral ulcerative keratitis. Patients with this condition experiencing ocular trauma or undergoing ocular surgery should be monitored closely.

CYP1A2*1F and GSTM1 alleles are associated with susceptibility to porphyria cutanea tarda

Porphyria cutanea tarda (PCT) is a cutaneous porphyria with sporadic (type 1) and familial (type 2) subtypes, both resulting from decreased hepatic uroporphyrinogen decarboxylase (UROD) activity. Environmental and genetic factors are involved in the development of PCT, and genetic variants in the cytochrome P450 (CYP ) genes, CYP1A1 and CYP1A2, have been implicated. We investigated the association between PCT and variants in CYP1A1, CYP1A2 and CYP2E1, and the glutathione-S-transferase (GST ) genes, GSTM1 and GSTT1. PCT diagnosis was based on urinary or plasma porphyrin profiles. Patients were classified as type 1 or 2 PCT based on UROD mutation analysis. The CYP1A2*1F promoter A allele frequency was significantly higher (P < 0.022) and the A/A genotype frequency marginally higher in PCT patients overall (P < 0.057), with the A/A genotype significantly more common in type 1 PCT (P < 0.043). The presence of the wild-type GSTM1 allele also was associated significantly with PCT (P < 0.019). Neither hemochromatosis (HFE) mutations, tobacco smoking, hepatitis C and HIV infection, ethanol consumption, nor estrogen use were associated with these allelic variants. Age at onset was significantly lower in type 2 PCT patients (P < 0.001), as observed previously. Thus, positive associations between PCT and the CYP1A2*1F promoter A allele and A/A genotype and the wild-type GSTM1 allele indicates that these functional hepatic biotransformation enzymes are risk factors for the development of this disease.