Ferrochelatase gene polymorphism analysis for accurate genetic counselling in erythropoietic protoporphyria

Cutaneous porphyrias part I: epidemiology, pathogenesis, presentation, diagnosis, and histopathology

The porphyrias are a group of disorders characterized by defects in the heme biosynthesis pathway. Many present with skin findings including photosensitivity, bullae, hypertrichosis, and scarring. Systemic symptoms may include abdominal pain, neuropsychiatric changes, anemia, and liver disease. With advances in DNA analysis, researchers are discovering the underlying genetic causes of the porphyrias, enabling family members to be tested for genetic mutations. Here we present a comprehensive review of porphyria focusing on those with cutaneous manifestations. In Part I, we have included the epidemiology, pathogenesis, presentation, diagnosis, and histopathology. Treatment and management options will be discussed in Part II.

Erythropoietic protoporphyria: spectrum of three cases

BACKGROUND

Erythropoietic protoporphyria is a rare photodermatosis of childhood, and the diagnosis can be delayed. A deficient ferrochelatase enzyme leads to accumulation of protoporphyrins in the dermis, causing phototoxic burning.

OBJECTIVE

To report three cases with great variability in severity of symptoms and age at diagnosis. We discuss clinical and biochemical findings, mutation analysis, and therapeutic options.

METHODS

We report three cases with different degrees of photosensitivity, laboratory results, psychosocial impact, and preventive and therapeutic treatments.

RESULTS

The diagnosis of erythropoietic protoporphyria was confirmed by both typical elevation of plasma porphyrins and the discovery of a mutated FECH gene.

CONCLUSION

Erythropoietic protoporphyria should be suspected in any cases of childhood photosensitivity. Systemic complications are unusual. Mutation analysis confirms the diagnosis. Photoprotection is the cornerstone of treatment.

Characteristics of 5-aminolaevulinic acid-induced protoporphyrin IX fluorescence in human skin in vivo

BACKGROUND/PURPOSE

Topical photodynamic therapy (PDT) is increasingly being used to treat skin cancers. Knowledge of the detailed characteristics of 5-aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence in diseased and normal skin is incomplete. Understanding the characteristics of PpIX fluorescence in normal skin may facilitate optimization of PDT regimes while minimizing side effects in the surrounding normal skin. We investigated the characteristics of ALA-induced PpIX fluorescence in normal skin.

METHODS

ALA was applied to the arm, back and leg skin of 21 healthy volunteers for 1-6 h, and PpIX fluorescence was measured for up to 24 h after ALA application using a fluorescent spectrometer. The effect of tape stripping on fluorescence was also examined.

RESULTS

Considerable inter-subject variation was observed in the time to reach peak PpIX fluorescence. Intra-subject variation in the time to peak fluorescence was dependent on ALA application time. Six hours after ALA application, no significant difference was observed in the degree of fluorescence achieved irrespective of ALA application times ranging between 1 and 6 h. PpIX fluorescence was reduced on the leg and increased by tape stripping.

CONCLUSIONS

Marked inter- and intra-subject variation in ALA-induced PpIX fluorescence occurs in normal human skin. ALA application time, body site and the state of the stratum corneum are all determinants of PpIX fluorescence within subjects and these factors need to be taken into account in optimization of PDT regimes.