New mutation identified in two sisters with adult-onset erythropoietic protoporphyria.

[erythropoietic protoporphyria]

Erythropoietic protoporphyria (EPP ; OMIM #177000 ) is a rare disease that usually presents in infancy or early childhood . The uncommon adult-onset EPP is often associated with acquired somatic mutations of the FECH gene , secondary to blood dyscracias .We investigated two sisters with adult-onset EPP .We found a novel germline mutation in the FECH gene , in trans with the common hypomorphic IVS 3 -48 C allele .T he adult presentation and identical genotypes of the two sisters suggests that the late development of the condition is to an extent a function of the mutation . The exact mechanism for this delayed penetrance is not clear , although these atypical cases raise the possibility of other genetic or nongenetic disease-modifying factors .