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.


METHODS
Cross-sectional questionnaire, biochemical and genetic study.


METHODS
Sweden.


METHODS
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.
Wahlin
S
S
Department of Gastroenterology and Hepatology, Porphyria Centre Sweden, Karolinska Institutet, Karolinska UniversityHospital, Stockholm, Sweden. staffan.wahlin@karolinska.se
Floderus
Y
Y
Stål
P
P
Harper
P
P
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003430:Cross-Sectional Studies; D004920:Erythropoiesis; D005260:Female; D005294:Ferrochelatase / Q000097:blood / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010787:Photosensitivity Disorders / Q000097:blood / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D011166:Porphyrins / Q000097:blood; D046351:Protoporphyria, Erythropoietic / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D013548:Sweden / Q000453:epidemiology; D014807:Vitamin D / Q000097:blood; D055815:Young Adult; D019207:beta Carotene / Q000627:therapeutic use
D011166:Porphyrins; D019207:beta Carotene; D014807:Vitamin D; D005294:Ferrochelatase