Erythropoietic Protoporphyria: Identification of Novel Mutations in the Ferrochelatase Gene and Comparison of Biochemical Markers versus Molecular Analysis as Diagnostic Strategies

Abstract

Background

Erythropoietic protoporphyria (EPP) results from an inherited deficiency of the last enzyme of the heme biosynthetic pathway, ferrochelatase (FC). EPP is usually inherited in an autosomal dominant fashion, and the mutations in the FC gene on chromosome 18q21.3 detected in EPP patients are heterogeneous.

Methods

In this study, we screened the FC gene for mutations in 12 patients from 10 unrelated families with EPP and their familiy members using heteroduplex analysis, automated sequencing, and restriction enzyme digestion.

Results

We detected 8 different mutations in these patients, including 1 missense mutation, 5 frameshift mutations, and 2 splice site mutations, 6 of which are previously undescribed.

Conclusions

We have established the molecular basis of EPP in 10 unrelated families, thereby providing further evidence for the heterogeneity in this disorder. Importantly, molecular diagnosis allowed revisions in the status of several clinically unaffected silent mutation carriers within the families. We compare the value of genetic research strategies with the combination of biochemical data and clinical phenotype as diagnostic tools to confirm a putative diagnosis in EPP.