Adesmia pinifolia, a Native High-Andean Species, as a Potential Candidate for Phytoremediation of Cd and Hg.

This study highlights Adesmia pinifolia, a native high-Andean species, as a potential candidate for the phytoremediation of soils contaminated with Cd and Hg. In this work, a semi-hydronic assay with different doses of Cd (3, 4.5, and 6 mg L-1) and Hg (0.8, 1.2, and 1.6 mg L-1) was analysed to evaluate the establishment of plants, antioxidant defence systems, oxidative stress, and the ability to accumulate heavy metals. The results indicate high survival rates (>80%); however, Cd significantly reduced shoot and root biomass, while Hg increased root biomass with the 1.6 mg L-1 treatment. Cd and Hg tend to accumulate more in roots (2534.24 µg/g and 596.4 µg g-1, respectively) compared to shoots (398.53 µg g-1 and 140.8 µg g-1, respectively). A significant decrease in the bioconcentration factor of Cd and Hg in roots was observed as metal levels increased, reaching the maximum value at 3 mg L-1 (805.59 ± 54.38) and 0.8 mg L-1 (804.54 ± 38.09). The translocation factor, <1 for both metals, suggests that translocation from roots to shoots is limited. An overproduction of reactive oxygen species (ROS) was observed, causing lipid peroxidation and oxidative damage to plant membranes. Tolerance strategies against subsequent toxicity indicate that enhanced glutathione reductase (GR) activity and glutathione (GSH) accumulation modulate Cd and Hg accumulation, toxicity, and tolerance.

An Improved Technique for Genotyping the ABCB1 Gene Variant of Exon 21.

The Multidrug Resistance protein (ABCB1, MDR1) is involved in the transport of xenobiotics and antiretroviral drugs. Some variants of the ABCB1 gene are of clinical importance; among them, exon 12 (c.1236C>T, rs1128503), 21 (c.2677G>T/A, rs2032582), and 26 (c.3435C>T, rs1045642) have a high incidence in Caucasians. Several protocols have been used for genotyping the exon 21 variants, such as allele-specific PCR-RFLP using adapted primer to generate a digestion site for several enzymes and automatic sequencing to detect the SNVs, TaqMan Allele Discrimination assay and High-Resolution Melter analysis (HRMA). The aim was to describe a new approach to genotype the three variants c.2677G>T/A for the exon 21 doing only one PCR with the corresponding primers and the digestion of the PCR product with two restriction enzymes: BrsI to identify A allele and BseYI to differentiate between G or T. An improvement of this methodology was also described. The proposal technique here described is demonstrated to be very efficient, easy, fast, reproducible, and cost-effective.

Clinical, biochemical, and genetic characterization of acute hepatic porphyrias in a cohort of Argentine patients.

BACKGROUND: Acute Hepatic Porphyrias (AHPs) are characterized by an acute neuroabdominal syndrome including both neuropsychiatric symptoms and neurodegenerative changes. Two main hypotheses explain the pathogenesis of nervous system dysfunction: (a) the ROS generation by autooxidation of 5-aminolevulinic acid accumulated in liver and brain; (b) liver heme deficiency and in neural tissues that generate an oxidative status, a component of the neurodegenerative process. METHODS: We review results obtained from Acute Intermittent Porphyria (AIP) and Variegate Porphyria (VP) families studied at clinical, biochemical, and molecular level at the CIPYP in Argentina. The relationship between the porphyric attack and oxidative stress was also evaluated in AHP patients and controls, to identify a marker of neurological dysfunction. RESULTS: We studied 116 AIP families and 30 VP families, 609 and 132 individuals, respectively. Genotype/phenotype relation was studied. Oxidative stress parameters and plasma homocysteine levels were measured in 20 healthy volunteers, 22 AIP and 12 VP individuals. CONCLUSION: No significant difference in oxidative stress parameters and homocysteine levels between the analyzed groups were found.

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.

Metabolismo del hemo: las dos caras de los efectos de la acumulación de precursores y porfirinas / Heme metabolism: the janus nature of precursorsand porphyrins / Metabolismo do hemo: as duas faces dos efeitos da acumulação de precursores e porfirinas

Las porfirias son enfermedades metabólicas consecuencia de fallas en la biosíntesis del hemo, caracterizadas por un patrón específico de acumulación y excreción de intermediarios, responsables de su patofisiología. En las porfirias agudas el exceso de ácido d-aminolevúlico (ALA) produce una sintomatología neuroabdominal asociada al daño oxidativo por formación de especies reactivas de oxígeno (ROS), originadas por autooxidaxión del ALA. En las cutáneas, la sintomatología es producto de la acumulación de porfirinas, que como el ALA, inducen la formación de ROS. Su desencadenamiento se precipita por factores endógenos (ayuno, estrés, hormonas) y/o exógenos (fármacos), en particular algunos anestésicos. Se presenta una revisión de los estudios bioquímicos y genéticos en pacientes con diferentes porfirias obtenidos en el Centro de Investigaciones de Porfirias y Porfirinas (CIPYP), durante los últimos 38 años, que permitieron ampliar el conocimiento sobre las bases moleculares sobre estas patologías. Se describen los logros resultantes del empleo de modelos experimentales de porfiria, inducida farmacológica o genéticamente, que contribuyeron a la clasificación de algunas drogas como prohibidas para pacientes con porfiria. Finalmente, las porfirinas generadoras de ROS, y por ende inductoras de muerte celular, tienen su aplicación para combatir infecciones por organismos hemo-deficientes como Trypanosoma cruzi y también para ser utilizadas como fotosensibilizadores en la terapia fotodinámica (TFD).

Porphyrias comprise a group of metabolic disorders of the heme biosynthesis pathway resulting in a specific accumulation and excretion of intermediates which are responsible for their pathophysiology. Acute porphyrias are characterized by acute neurovisceral symptoms due to the overproduction and accumulation of d-aminolevulinic acid (ALA) which leads to an oxidative damage resulting from the formation of reactive oxygen species (ROS). In cutaneous porphyrias, the symptomatology is a result of porphyrin accumulation which also induces ROS moulding. In both cases, their clinical signs are precipitated by endogenous factors (stress, hormones, low calories intake) and/or exogenous drugs, in particular some anaesthetics. A review of the biochemical and genetic results obtained from patients with different porphyrias, diagnosed at the CIPYP during the last 38 years is presented here, aimed at obtaining additional evidence about the molecular nature of these disorders. The achievements obtained from experimental porphyria models -pharmacologically or genetically induced- are also described, which contributed to the classification of some drugs as prohibited for their use in porphyric patients. Finally, as porphyrins produce ROS and therefore cellular death, they can be used to treat infections by heme-deficient organisms like Trypanosoma cruzi and also as photosensitizers in photodynamic therapy (TFD).

As Porfirias são doenças metabólicas decorrentes de falhas na biossíntese do Hemo, caracterizadas por um padrão específico de acumulação e excreção de intermediários responsáveis de sua patofisiologia. Nas Porfirias Agudas, o excesso de ácido δ-aminolevulínico (ALA) produz uma sintomatologia neuroabdominal associada ao dano oxidativo por formação de espécies reativas de oxigênio (ROS), decorrentes da auto-oxidação do ALA. Nas Cutâneas a sintomatologia é produto da acumulação de porfirinas, que como o ALA, induzem a formação de ROS. Seu desencadeamento precipita-se por fatores endógenos (jejum, estresse, hormônios) e/ou exógenos (fármacos), especialmente alguns anestésicos. Apresenta-se uma revisão dos estudos bioquímicos e genéticos em pacientes com diferentes Porfirias obtidos no Centro de Investigações de Porfirias e Porfirinas (CIPYP), durante os últimos 38 anos, que permitiram ampliar o conhecimento sobre as bases moleculares destas patologias. Descrevem-se as conquistas resultantes do uso de modelos experimentais de Porfiria, induzida farmacológica ou geneticamente, que contribuíram à classificação de algumas drogas como proibidas para pacientes com Porfiria. Afinal, as porfirinas geradoras de ROS e, por conseguinte, indutoras de morte celular têm sua aplicação para combater infecções por organismos hemo-deficientes como Trypanosoma cruzi e também ser utilizadas como fotossensibilizadores na terapia fotodinâmica (TFD).

Acute intermittent porphyria in Argentina: an update.

Porphyrias are a group of metabolic diseases that arise from deficiencies in the heme biosynthetic pathway. A partial deficiency in hydroxymethylbilane synthase (HMBS) produces a hepatic disorder named Acute Intermittent Porphyria (AIP); the acute porphyria is more frequent in Argentina. In this paper we review the results obtained for 101 Argentinean AIP families and 6 AIP families from foreign neighbour countries studied at molecular level at Centro de Investigaciones sobre Porfirinas y Porfirias (CIPYP). Thirty-five different mutations were found, of which 14 were described for the first time in our population. The most prevalent type of mutations was the missense mutations (43%) followed by splice defects (26%) and small deletions (20%). An odd case of a double heterozygous presentation of AIP in a foreign family from Paraguay is discussed. Moreover, it can be noted that 38 new families were found carrying the most frequent mutation in Argentina (p.G111R), increasing to 55.66% the prevalence of this genetic change in our population and adding further support to our previous hypothesis of a founder effect for this mutation in Argentina. Identification of patients with an overt AIP is important because treatment depends on an accurate diagnosis, but more critical is the identification of asymptomatic relatives to avoid acute attacks which may progress to death.

Characterization of variegate porphyria mutations using a minigene approach.

Porphyrias are a group of metabolic diseases that affect the skin and/or nervous system. In 2008, three unrelated patients were diagnosed with variegate porphyria at the CIPYP (Centro de Investigaciones sobre Porfirinas y Porfirias). Sequencing of the protoporphyrinogen oxidase gene, the gene altered in this type of porphyria, revealed three previously undescribed mutations: c.338+3insT, c.807G>A, and c.808-1G>C. As these mutations do not affect the protein sequence, we hypothesized that they might be splicing mutations. RT-PCRs performed on the patient's mRNAs showed normal mRNA or no amplification at all. This result indicated that the aberrant spliced transcript is possibly being degraded. In order to establish whether they were responsible or not for the patient's disease by causing aberrant splicing, we utilized a minigene approach. We found that the three mutations lead to exon skipping; therefore, the abnormal mRNAs are most likely degraded by a mechanism such as nonsense-mediated decay. In conclusion, these mutations are responsible for the disease because they alter the normal splicing pathway, thus providing a functional explanation for the appearance of disease and highlighting the use of minigene assays to complement transcript analysis.

Haplotype Study in Argentinean Variegate Porphyria Patients.

BACKGROUND/AIMS: The porphyrias are genetically heterogeneous diseases, and each mutation is exclusive to one or two families. Among the mutations responsible for variegate porphyria in our country, c.1042_1043insT stands out, since it was described only in Argentina and is present in about 40% of genetically diagnosed families. Thus, we hypothesized the possible existence of a common ancestor for the mutation in our population. METHODS: We conducted a study based on microsatellite (short tandem repeats) haplotypes. RESULTS: We found a common haplotype in all of the patients carrying the common mutation. The age of the mutation was estimated to be about 375 years. CONCLUSION: There is a recent founder effect in our population for this particular genetic alteration in variegate porphyria.

Molecular analysis of the UROD gene in 17 Argentinean patients with familial porphyria cutanea tarda: characterization of four novel mutations.

Porphyria cutanea tarda (PCT) is caused by decreased activity of uroporphyrinogen decarboxylase (UROD) in the liver. The disease usually occurs in adulthood and is characterized by cutaneous photosensitivity, hyperpigmentation, skin fragility and hypertrichosis, due to the accumulation of porphyrins produced by oxidation of uroporphyrinogen and other highly carboxylated porphyrinogens overproduced as a result of the enzyme deficiency. PCT is generally sporadic, but about 20-30% of patients have familial-PCT (F-PCT) which is associated with heterozygosity of mutations in the UROD gene. In the present study we have found the molecular defect in seventeen unrelated Argentinean patients with F-PCT, identifying a total of eleven UROD gene mutations: four novel and seven previously described. The novel mutations were: a guanine insertion at the 5' splice junction of intron 2, a three nucleotide deletion causing the lost of valine 90, a deletion of 22 bp in exon 6 and a deletion of part of the polyadenylation signal. Prokaryotic expression studies showed that the novel amino acid deletion resulted in an inactive protein. Mutations c.10insA and p.M165R, previously found in Argentinean patients, were recurrent in this study; they are the most frequent in Argentina accounting for 40% of the mutant alleles characterized to date.

Functional Characterization of Five Protoporphyrinogen oxidase Missense Mutations Found in Argentinean Variegate Porphyria Patients.

A partial deficiency in protoporphyrinogen oxidase (PPOX) produces the acute/cutaneous (or mixed) variegate porphyria (VP), the third most frequent porphyria in Argentina. This autosomal dominant disorder is clinically characterized by skin lesions and/or acute neurovisceral attacks. The precise diagnosis of patients with a symptomatic VP is essential to provide accurate treatment. It is also critical to identify asymptomatic relatives to avoid precipitating factors and prevent acute attacks.Functional consequences of five PPOX missense mutations were evaluated in a prokaryotic expression system. Three mutations were found in families previously reported c.101A>T (p.E34V), c.670T>G (W224G), c.995G>C (G332A) and two were novel findings c.227C>T (p.S76F), c.1265A>G (p.Y422C). All mutations were identified in heterozygotes with reduced PPOX activity and variable clinical expression of the disease, including asymptomatic cases. Prokaryotic expression showed that all five missense mutations decreased the PPOX activity, demonstrating their detrimental effect on enzyme function, and thus, providing evidence for their causative role in VP. These results reinforce the importance of molecular genetic analysis for VP diagnosis and especially the usefulness of prokaryotic expression of missense mutations to assess their deleterious effect on PPOX activity.MM and BXG contributed equally to the publication. RES and MVR share senior authorship.

Novel null-allele mutations and genotype-phenotype correlation in Argentinean patients with erythropoietic protoporphyria.

Erythropoietic protoporphyria (EPP) is an inherited disorder of porphyrin metabolism in which decreased activity of ferrochelatase (FECH) leads to accumulation of protoporphyrin IX (PP IX) in red blood cells, plasma, liver, and bile, and increased PP IX excretion in feces. Clinically, EPP is characterized by photosensitivity that begins in early childhood and includes burning, swelling, itching, and painful erythema in sun-exposed areas. Chronic liver disease is an important complication in a minority of EPP patients, and in some cases liver transplantation has been performed. So far, about 110 different mutations and several polymorphisms have been characterized in the human FECH gene. The relationship between mutations, polymorphisms, and porphyria development in Argentinean patients was investigated. This is the first genetic study carried out in the Argentinean population. In five Argentinean EPP families we detected three novel mutations: a deletion (451delT) producing a stop codon located 18 codons downstream from the mutation and two splicing mutations: IVS1-2A>G leading to exon 2 skipping and IVS4-2A>G, which causes the loss of the first 48 bp of exon 5. We also found two previously described mutations: C343T and 400delA, which produce stop codons. All patients had an FECH activity 25% of normal and also had the polymorphisms -251A>G in the promoter region and IVS1-23 C>T and IVS3-48 T>C. Our findings provide supporting evidence for the concept that the inheritance of the low expression allele IVS3-48C in trans with a mutation in the FECH gene is necessary for EPP to become clinically manifest.

Genetic and biochemical studies in Argentinean patients with variegate porphyria.

BACKGROUND: A partial deficiency in Protoporphyrinogen oxidase (PPOX) produces the mixed disorder Variegate Porphyria (VP), the second acute porphyria more frequent in Argentina. Identification of patients with an overt VP is absolutely important because treatment depends on an accurate diagnosis but more critical is the identification of asymptomatic relatives to avoid acute attacks which may progress to death. METHODS: We have studied at molecular level 18 new Argentinean patients biochemically diagnosed as VP. PPOX gene was amplified in one or in twelve PCR reactions. All coding exons, flanking intronic and promoter regions were manual or automatically sequenced. For RT-PCR studies RNA was retrotranscripted, amplified and sequenced. PPOX activity in those families carrying a new and uncharacterized mutation was performed. RESULTS: All affected individuals harboured mutations in heterozygous state. Nine novel mutations and 3 already reported mutations were identified. Six of the novel mutations were single nucleotide substitutions, 2 were small deletions and one a small insertion. Three single nucleotide substitutions and the insertion were at exon-intron boundaries. Two of the single nucleotide substitutions, c.471G>A and c.807G>A and the insertion (c.388+3insT) were close to the splice donor sites in exons 5, 7 and intron 4 respectively. The other single nucleotide substitution was a transversion in the last base of intron 7, g.3912G>C (c.808-1G>C) so altering the consensus acceptor splice site. However, only in the first case the abnormal band showing the skipping of exon 5 was detected. The other single nucleotide substitutions were transversions: c.101A>T, c.995G>C and c.670 T>G that result in p.E34V, p.G332A and W224G aminoacid substitutions in exons 3, 10 and 7 respectively. Activity measurements indicate that these mutations reduced about 50% PPOX activity and also that they co-segregate with this reduced activity value. Two frameshift mutations, c.133delT and c.925delA, were detected in exons 3 and 9 respectively. The first leads to an early termination signal 22 codons downstream (p.S45fsX67) and the second leads to a stop codon 5 codons downstream (p.I309fsX314). One reported mutation was a missense mutation (p.G232R) and 2 were frameshift mutations: c.1082insC and 1043insT. The last mutation was detected in six new apparently unrelated Argentinean families. CONCLUSION: Molecular analysis in available family members revealed 14 individuals who were silent carriers of VP. Molecular techniques represent the most accurate approach to identify unaffected carriers and to provide accurate genetic counselling for asymptomatic individuals. The initial screening includes the insertion search.

Porfiria Congénita Eritropoyética en la Argentina: 4 niños y un caso de manifestación tardía / Congenital Erythropoietic Porphyria in Argentina: 4 children and one late onset case

Las porfirias son la consecuencia de fallas en el metabolismo del hemo. La Porfiria Congénita Eritropoyética (PCE) (enfermedad de Günther) es una porfiria cutánea rara que se transmite en forma autosómica recesiva. Se produce debido a la presencia de mutaciones en el gen de la uroporfirinógeno III sintetasa (UROIII-S) que llevan a una marcada disminución de su actividad y a la producción y acumulación de elevadas cantidades de porfirinas de la serie isomérica I en plasma, tejidos y huesos, responsables de la severa sintomatología cutánea que generalmente presentan los pacientes con esta porfiria. Se han descripto sólo alrededor de 200 casos a nivel mundial. Su expresión clínica es muy heterogénea, encontrándose desde casos muy graves con severo compromiso cutáneo, transfusión-dependiente, hasta casos leves con escasa sintomatología cutánea. Se presentan 5 casos de pacientes argentinos con PCE, 4 infantiles y uno de manifestación tardía, diagnosticados en el Centro de Investigaciones sobre Porfirinas y Porfirias (CIPYP), que constituyen, hasta el momento, los únicos registrados en Argentina. Se encontraron elevadas cantidades de porfirinas en plasma, sangre, orina y materia fecal y un patrón de porfirinas con predominio de la serie I. La actividad de la UROIII-S estaba reducida en un 25-44% con respecto al valor normal. El diagnóstico certero y precoz de esta porfiria es fundamental para aplicar tempranamente el tratamiento adecuado en cada caso y brindarle al paciente una mejor calidad de vida.

Porphyrias are metabolism disorders caused by a partial deficiency in one of the heme biosynthetic pathway enzymes. Congenital Erythropoietic Porphyria, also termed Günther disease, is extremely rare and is inherited as an autosomal recessive trait that results from the markedly deficient activity of the fourth enzyme in the heme biosynthetic pathway, Uroporphyrinogen III synthase (UROIII-S). This enzyme deficiency leads to an increased production and accumulation of the nonphysiological and phototoxic type I porphyrins responsible for the typical clinical manifestations. The disease severity is markedly heterogeneous, ranging from severe transfusion dependency throughout life to milder adult cases with only cutaneous photosensitivity. Only 200 cases have been described all over the world so far. In this work five Argentinean CEP patients are presented, 4 infantile and one late onset case, diagnosed in the CIPYP which are, as far as it is known, the only cases described in Argentina. Increased amounts of porphyrins were found in plasma, blood, urine and faeces, together with high amounts of the pathogenic type I isomer. Enzyme activity was reduced to 25-44% respect to normal values. Early diagnosis is important for correct treatment so as to prevent the characteristic mutilation of the disease and to improve patient´s life quality.

CYP2D6 polymorphisms in patients with porphyrias.

The cytochrome P-450 (CYP) isoenzymes, a superfamily of heme proteins which are the terminal oxidases of the mixed function oxidases system, metabolize more than 70% of all clinically approved drugs. The highly polymorphic CYP2D6 isoform metabolizes more than 25% of most common drugs, and the phenotypes of the 70-plus allelic variants range from compromised to excessive enzymatic activity. Porphyrias are a group of inherited or acquired metabolic disorders of heme biosynthesis, due to a specific decrease in the activity of one of the enzymes of the heme pathway. Clinical signs and symptoms of porphyrias are frequently associated with exposure to precipitating agents, including clinically approved drugs. CYP enzymes, including CYP2D6, participate in the metabolism of some porphyrinogenic drugs, leading to the deregulation of heme biosynthesis. Considering that some of the drugs not recommended for use in porphyric patients are metabolized by CYP2D6, the presence of CYP2D6 polymorphisms in porphyric patients would influence the triggering of the disease when these individuals receive a precipitating agent that is metabolized by CYP2D6. To investigate CYP2D6 polymorphisms in porphyric patients, healthy Argentinean volunteers, porphyric patients, and a group of individuals with high levels of iron were studied. Results indicated that the CYP2D6*3 and CYP2D6*4 alleles, in particular, would be linked to the onset of disease. Predictive genotyping for CYP2D6 in porphyric patients holds promise as a method to improve the clinical efficacy of drug therapy and to personalize drug administration for these patients.

The role of inherited and acquired factors in the development of porphyria cutanea tarda in the Argentinean population.

BACKGROUND: Inherited and environmental factors are implicated in the expression of porphyria cutanea tarda (PCT); the contribution of each factor depends on the population. OBJECTIVE: To provide a review of PCT cases diagnosed in Argentina over 24 years and evaluate the role of different precipitating factors in its pathogenesis. Methods Plasma and urinary porphyrin levels and erythrocyte uroporphyrinogen decarboxylase (URO-D) activity were determined. Potential precipitating factors were identified in each patient. Additional tests for hepatitis C virus (HCV) and hemochromatosis gene mutations were carried out. RESULTS: Several factors (mainly alcohol abuse in men and estrogen ingestion in women), alone or combined were identified in our patients. Prevalence of HCV infection was 35.2%. Inherited URO-D deficiency occurs in 25.0% of cases. H63D was the most common hemochromatosis gene mutation. High incidence of PCT associated with HIV infection was found. CONCLUSIONS: PCT is multifactorial. Therefore, knowledge of all risk factors in each patient is important for the management of the disease.

Estudios genéticos de las porfirias agudas en Argentina / Genetic studies of acute porphyrias in Argentina

Las porfirias constituyen una familia de enfermedades que son la consecuencia de una deficiencia parcial y específica de una de las enzimas del camino del hemo. Pueden ser adquiridas o genéticas. Las porfirias se pueden clasificar en base a sus manifestaciones clínicas en cutáneas, agudas y mixtas. La porfiria aguda intermitente (PAI) es el tipo más común entre las porfirias agudas, se transmite en forma autosómica dominante y está causada por un defecto en el gen que codifica para la enzima porfobilinógeno deaminasa; su prevalencia en la Argentina es de 1:125.000. Una deficiencia parcial en la protoporfirinógeno oxidasa, otra de las enzimas del camino del hemo, produce la porfiria variegata (PV), la segunda porfiria aguda más frecuente en éste país, heredada también en forma autosómica dominante, con una frecuencia de 1:600.000. En éste trabajo se describen todas las mutaciones detectadas hasta el momento en 43 pacientes con PAI y en 9 pacientes con PV no relacionados (AU)

Estudios genéticos de las porfirias agudas en Argentina / Genetic studies of acute porphyrias in Argentina

Las porfirias constituyen una familia de enfermedades que son la consecuencia de una deficiencia parcial y específica de una de las enzimas del camino del hemo. Pueden ser adquiridas o genéticas. Las porfirias se pueden clasificar en base a sus manifestaciones clínicas en cutáneas, agudas y mixtas. La porfiria aguda intermitente (PAI) es el tipo más común entre las porfirias agudas, se transmite en forma autosómica dominante y está causada por un defecto en el gen que codifica para la enzima porfobilinógeno deaminasa; su prevalencia en la Argentina es de 1:125.000. Una deficiencia parcial en la protoporfirinógeno oxidasa, otra de las enzimas del camino del hemo, produce la porfiria variegata (PV), la segunda porfiria aguda más frecuente en éste país, heredada también en forma autosómica dominante, con una frecuencia de 1:600.000. En éste trabajo se describen todas las mutaciones detectadas hasta el momento en 43 pacientes con PAI y en 9 pacientes con PV no relacionados