Porfiria cutánea tarda familiar: Presentación de un caso y revisión de la literatura / Cutaneous porphyria tarda familiar: presentation of a case and review of the literature

La porfiria cutánea tarda (PCT) es una enfermedad metabólica, crónica, que se produce por fallas en el metabolismo del hemo, debidas a deficiencia en la actividad de la enzima URO decarboxilasa. Se produce con más frecuencia en el sexo masculino y en adultos de mediana edad. Se clasifica en adquiridas y familiares, estas últimas de menor frecuencia, de acuerdo al antecedente familiar y al sitio de actividad de la enzima UROD. Las manifestaciones clínicas características son fragilidad cutánea, hipertricosis, fotosensibilidad y ampollas en áreas fotoexpuestas. El tratamiento de la enfermedad consiste en discontinuar los factores desencadenantes, reducir la sobrecarga hepática de hierro a través de flebotomías o el uso de antipalúdicos para movilizar el exceso de porfirinas. Presentamos el caso de una paciente femenina, con antecedente materno de PCT, que presentó manifestaciones clínicas en la adolescencia, asociado a factores desencadenantes y con excelente respuesta al tratamiento con flebotomías (AU)

Porphyria cutanea tarda (PCT) is a chronic metabolic disease caused by failures in heme metabolism, due to deficiency in the activity of the enzyme URO decarboxylase. Men and middle-age adults are often more affected. According to family history and the site of enzyme activity, PCT is classified in acquired or familial. Clinical features are skin fragility, hypertrichosis, photosensitivity and blisters on sun-exposed areas. Treatment of this disease is based on discontinuing the triggers, reduce liver iron overload trough phlebotomies or the use of antimalarial agents to mobilize excess porphyrins. A case of a female patient with a maternal history of PCT who presented clinical manifestations in adolescence, associated with triggers factors and excellent response to treatment with phlebotomies is reported (AU)

Porphyria cutanea tarda: multiplicity of risk factors including HFE mutations, hepatitis C, and inherited uroporphyrinogen decarboxylase deficiency.

The coexistence of factors considered to contribute to development of porphyria cutanea tarda was studied in 39 consecutive patients. Highly prevalent factors were alcohol intake in 79%, smoking in 86%, hepatitis C virus infection in 74%, estrogen use in 73% of 11 females, and at least one mutation in the HFE (hereditary hemochromatosis) gene in 65%. The C282Y mutation was found in 29%, H63D in 47%, and S65C in 0%. HFE genotypes included C282Y/C282Y in 9%, H63D/H63D in 9%, C282Y/H63D in 12%, C282Y/wild type in 9%, and H63D/wild type in 26%. Less prevalent were HIV infection in 15% (or 25% of those tested, N = 24) and erythrocyte uroporphyrinogen decarboxylase deficiency, which distinguishes familial (type 2) from "sporadic" (type 1) porphyria cutanea tarda, in 19%. Multiple contributing factors coexisted in both types 1 and 2, with 92% of all patients having three or more factors. These observations indicate that this porphyria is multifactorial in the individual patient, and therefore is seldom attributable to a single identifiable cause. Profiling for all potentially contributing factors is important for individualizing management.

Porphyrin biosynthesis intermediates are not regulating delta-aminolevulinic acid transport in Saccharomyces cerevisiae.

In Saccharomyces cerevisiae, as in all eukaryotic organisms, delta-aminolevulinic acid (ALA) is a precursor of porphyrin biosynthesis, a very finely regulated pathway. ALA enters yeast cells through the gamma-aminobutyric acid (GABA) permease Uga4. The incorporation of a metabolite into the cells may be a limiting step for its intracellular metabolization. To determine the relationship between ALA transport and ALA metabolization, ALA incorporation was measured in yeast mutant strains deficient in the delta-aminolevulinic acid-synthase, uroporphyrinogen III decarboxylase, and ferrochelatase, three enzymes involved in porphyrin biosynthesis. Results presented here showed that neither intracellular ALA nor uroporphyrin or protoporphyrin regulates ALA incorporation, indicating that ALA uptake and its subsequent metabolization are not related to each other. Thus a key metabolite as it is, ALA does not have a transport system regulated according to its role.

Correction of uroporphyrinogen decarboxylase deficiency (hepatoerythropoietic porphyria) in Epstein-Barr virus-transformed B-cell lines by retrovirus-mediated gene transfer: fluorescence-based selection of transduced cells.

Hepatoerythropoietic porphyria (HEP) is an inherited metabolic disorder characterized by the accumulation of porphyrins resulting from a deficiency in uroporphyrinogen decarboxylase (UROD). This autosomal recessive disorder is severe, starting early in infancy with no specific treatment. Gene therapy would represent a great therapeutic improvement. Because hematopoietic cells are the target for somatic gene therapy in this porphyria, Epstein-Barr virus-transformed B-cell lines from patients with HEP provide a model system for the disease. Thus, retrovirus-mediated expression of UROD was used to restore enzymatic activity in B-cell lines from 3 HEP patients. The potential of gene therapy for the metabolic correction of the disease was demonstrated by a reduction of porphyrin accumulation to the normal level in deficient transduced cells. Mixed culture experiments demonstrated that there is no metabolic cross-correction of deficient cells by normal cells. However, the observation of cellular expansion in vitro and in vivo in immunodeficient mice suggested that genetically corrected cells have a competitive advantage. Finally, to facilitate future human gene therapy trials, we have developed a selection system based on the expression of the therapeutic gene. Genetically corrected cells are easily separated from deficient ones by the absence of fluorescence when illuminated under UV light.

Porfiria cutánea tarda esclerodermiforme: presentación de cuatro casos y revisión de la literatura / Sclerodermic porphyria cutanea tarda: report of 4 casis and a review of the literature

La porfiria cutánea tarda esclerodermiforme (PCTE) es una forma poco frecuente de la presentación de la porfiria cutánea tarda (PCT), representando el 18-33 por ciento de los casos. Se caracteriza por manifestarse con placas esclerodermiformes de aparición insidiosa y tardía en el curso de la enfermedad. El déficit de la actividad de la enzima uroporfirinógeno decarboxilasa (UPDC), lleva a la acumulación de metabolitos intermedios responsables de las manifestaciones clínicas y bioquímicas. Se presentan cuatro pacientes con PCTE estudiados en nuestro Servicio, en un período de cuatro años (1992-1996)

Porfiria cutanea tarda: detección de una mutación en la uroporfirinogena decarboxilasa mediante RT-PCR y secuenciación directa / Porphyria cutanea tarda: detection of the new mutation in the uroporphyrinogen decarboxylase intervening RT-PCR direct sequenced

La porfiria cutánea tardía familiar (PCT-F) y la porfiria hepatoeritropoyética (PHE), son dos porfirias cutáneas causadas por la deficiencia en la actividad de la Uroporfirinógeno Decarboxilasa (URO-D), que es la quinta enzima del camino biosintético del hemo y cataliza la conversión del Uroporfirinógeno(UROgen) a Coproporfirinógeno (COPROgen). La PCT-F es dominante y la actividad de la URO-D está reducida a un 50 por ciento en todos los tejidos mientras que la PHE es recesiva y en ella la activcidad de la URO-D es sólo de un 5-10 por ciento del valor normal. El gen de la URO-D está compuesto por 10 exones dentro de 3 kb. Partiendo de 15 ml de sangre entera, y realizando separación de linfocitos, extracción de ARN, RT-PCR y secuenciación directa de las casi 1,2 del ADNc de la URO-D, se ha encontrado en un paciente argentina con PCT-F una mutación nueva caracterizada por la deleción del exón 9, La PCR y secuenciación del ADN genómico revelo que la deleción es causada por la transición G A en la última base del exón 9 que afecta la maduración ("splicing") del mensajero ya que inactivaría el sitio doner de "splicing" del intrón 9, como consecuencia se produce la unión entre el exón 8 y 10 lo cual a su vez lleva a un corrimiento de marco de lectura, que predice la síntesis de una proteína truncada con una perdida total de casi el 20 por ciento de sus aminoácidos

Uroporphyrinogen decarboxylase: complete human gene sequence and molecular study of three families with hepatoerythropoietic porphyria.

A deficiency in uroporphyrinogen decarboxylase (UROD) enzyme activity, the fifth enzyme of the heme biosynthetic pathway, is found in patients with sporadic porphyria cutanea tarda (s-PCT), familial porphyria cutanea tarda (f-PCT), and hepatoerythropoietic porphyria (HEP). Subnormal UROD activity is due to mutations of the UROD gene in both f-PCT and HEP, but no mutations have been found in s-PCT. Genetic analysis has determined that f-PCT is transmitted as an autosomal dominant trait. In contrast, HEP, a severe form of cutaneous porphyria, is transmitted as an autosomal recessive trait. HEP is characterized by a profound deficiency of UROD activity, and the disease is usually manifest in childhood. In this study, a strategy was designed to identify alleles responsible for the HEP phenotype in three unrelated families. Mutations of UROD were identified by direct sequencing of four amplified fragments that contained the entire coding sequence of the UROD gene. Two new missense mutations were observed at the homoallelic state: P62L (proline-to-leucine substitution at codon 62) in a Portuguese family and Y311C (tyrosine-to-cysteine substitution at codon 311) in an Italian family. A third mutation, G281E, was observed in a Spanish family. This mutation has been previously described in three families from Spain and one from Tunisia. In the Spanish family described in this report, a paternal uncle of the proband developed clinically overt PCT as an adult and proved to be heterozygous for the G281E mutation. Mutant cDNAs corresponding to the P62L and Y311C changes detected in these families were created by site-directed mutagenesis. Recombinant proteins proved to have subnormal enzyme activity, and the Y311C mutant was thermolabile.

Porfiria cutánea tarda asociada a virus de la hepatitis c / Porphyria cutanea tarda associated with hepatitis c virus

La porfiria cutánea tarda es la más frecuente de las porfirias. Los cambios esclerodermiformes, si bien conocidos, no son habituales. Al virus de la hepatitis C se lo ha encontrado asociado a las porfirias cutáneas tardas. Algunos autores consideran que puede ser el factor causal de la disfunción hepática, afectando el metabolismo de las porfirias; otros en cambio consideran que actuaría como un co-factor, al igual que el alcohol, los estrógenos, ciertos tóxicos, etc. Presentamos un varón de 55 años de edad, que presentó una porfiria cutánea tarda con cambios esclerodermiformes cutáneos, asociada al virus de la hepatitis C. Se discute su asociación a este virus y el rol patogénico del mismo en la porfiria

[Porphyria cutanea tarda and hepatoerythropoietic porphyria].

Porphyria cutanea tarda (PCT) is induced by an enzyme deficiency of hepatic uroporphyrinogen decarboxylase activity. As the result of this enzyme deficiency, uroporphyrin and coproporphyrin accumulate to the skin and other organs. These porphyrins are excreted into urine because of their easy solubility in water. Exposure to the sunlight of the porphyrin-rich skin induces cutaneous changes. Porphyria cutanea tarda develops mainly in middle-aged males, sometimes in females. Ethylalcohol, estrogenic hormones, and hemodialysis are reported as provocative factors. Hyperpigmentation on exposed areas, skin fragility, vesicles and erosions are common in PCT. Histopathologically, subepidermal bulla is a characteristic finding in PCT. PAS positive materials are also prominent around the small blood vessels in the dermis and dermo-epidermal junctions. Hepatoerythropoietic porphyria (HEP) is usually manifest in early childhood with dark urine and reveals severe cutaneous photosensitivity. This disease is a homozygous form of type II PCT.

The porphyrias and hepatocellular carcinoma.

Hepatocellular carcinoma probably represents the final step of the effects of the various precipitating agents for porphyria cutanea tarda, such as alcohol, drugs, hormones, and hepatitis C infection. Risk factors associated with its development include male gender, age over 50 years, liver fibrosis or cirrhosis, and a long history (over 10 years) of symptomatic porphyria cutanea tarda.

Hereditary uroporphyrinogen-decarboxylase deficiency predisposing porphyria cutanea tarda (chronic hepatic porphyria) in females after oral contraceptive medication.

Porphyria cutanea tarda (PCT) was diagnosed in 27 women aged 23-48 years (mean, 35 years) who had been under oral-hormonal-contraceptive medication for 1-18 years, in 3 women under substitutional estrogen treatment in the menopause, and in 2 men aged 65 and 76 years after estrogen treatment of prostatic carcinoma. In all patients, total urinary porphyrin excretion was elevated, with an average uro- and heptacarboxyporphyrin predominance of 88%, thus proving PCT. Of the patients, 84% showed a significant decrease of erythrocyte uroporphyrinogen-decarboxylase (UD; EC 4.1.1.37) activity to approximately 50% of control levels suggesting a hereditary predisposition for the development of a chronic hepatic porphyria. Estrogens and alcohol are capable of reducing hepatic UD activity. Women with hereditary red cell UD deficiency may be regarded as predisposed to PCT when under estrogen intake, especially in combination with the potentiating influence of alcohol and chronic liver disease. Normal erythrocyte UD values in patients with additive alcohol consumption may implicate a stronger inhibitory effect for alcohol on UD, suggesting a merely toxic form of chronic hepatic porphyria.