Biochemical abnormality in erythropoietic protoporphyria: cause and consequences

A Novel Mutation in the FECH Gene in a Czech Family with Erythropoietic Protoporphyria and a Population Study of IVS3-48C Variant Contributing to the Disease

Erythropoietic protoporphyria (EPP), a chronic erythropoietic porphyria, is characterized by excess accumulation of protoporphyrin, particularly in erythroid cells. EPP inheritance is complex, almost always associated with two molecular defects. In most EPP patients, clinical expression requires coinheritance of a private ferrochelatase (FECH) mutation trans- to a hypomorphic FECH*IVS3-48C allele. This leads to a decrease of FECH activity below the critical threshold. This is characterized by cutaneous photosensitivity in early childhood such as itching, burning, swelling and redness in sun-exposed areas. Hepatic failure occurs in some patients (about 1-10 % of EPP patients), which may necessitate liver transplantation. We investigated a Czech family with two patients with manifested EPP in four generations. We found a novel mutation, c.84G >A, in the FECH gene in four individuals including proband and his mother (G84A transition in exon 2; p.W28*). Both clinically manifested probands inherited the hypomorphic IVS3-48C allele as well, while two clinically latent individuals with FECH mutation did not. To address the question whether the relatively low incidence of EPP in the Czech Republic might be due to lower frequency of the IVS3-48C allele, we screened for the frequency of the low expression allele in a control Czech (West Slaves) Caucasian population. Such study has not been performed in any Slavic population. Among 312 control individuals, there were no IVS3-48C/C (c.68-23C-T) homozygotes; 35 IVS3-48C/T heterozygous individuals were detected. The frequency of IVS3-48C allele was thus found to be 5.5 % in the Czech population, comparable to most West Caucasian populations.

Erythropoietic protoporphyria in Sweden: demographic, clinical, biochemical and genetic characteristics

OBJECTIVE

To investigate the demographic, clinical, biochemical and genotypic features of patients with erythropoietic protoporphyria (EPP) in a Swedish cohort.

DESIGN

Cross-sectional questionnaire, biochemical and genetic study.

SETTING

Sweden.

SUBJECTS

Fifty-one Swedish individuals known in 2008 to have EPP confirmed by molecular diagnosis. There were no exclusion criteria; all patients were included in the demographic and genetic study. A total of 92% participants completed the questionnaire study and 82% the biochemical study.

RESULTS

The prevalence of EPP was 1 : 180,000. Nine novel ferrochelatase gene mutations were found. The most commonly reported age at onset of symptoms was the first year of life and the mean age at diagnosis was 22 years. Painful photosensitivity was the main symptom. Exogenous factors other than sunlight were frequently reported to cause cutaneous symptoms. One in five patients reported a positive effect of beta-carotene therapy. A marked impact of EPP on quality of life was reported. Women had a significantly lower mean erythrocyte protoporphyrin concentration than men. Of all participants, 84% had insufficient vitamin D concentrations, 44% had below normal serum ferritin or transferrin saturation levels and red cell abnormalities were common.

CONCLUSIONS

The notably delayed diagnosis suggests the need for an increased awareness of EPP. Disturbed erythropoiesis, biochemical signs of iron deficiency and low vitamin D levels are frequent findings in this disease. New and better treatments are needed as current treatment options for symptom amelioration are limited. Vitamin D supplementation should be considered.

Environmental dermatology in childhood: photosensitivity

Recently, sunlight-induced damage of healthy human skin, including skin malignancies and a large scale of photodermatoses representing a diverse group of diseases, have increased in childhood as a result of unfavorable environmental changes. This article yields an overview of the diagnosis, the clinical features and the treatment of these conditions and disorders and also reveals perspectives. Some diseases are more frequent in the pediatric population than in adulthood, whereas others heal spontaneously during adolescence and vice versa. The majority of cases are idiopathic photodermatoses, mainly polymorphic light eruption. Photosensitivity may be an early symptom of genetic disorders, such as porphyria, or very rare genophotodermatoses. Photosensitivity, secondary to topical or systemic external agents as well as photoexacerbated dermatoses, is not so frequent in childhood. Effective photoprotection is crucial.