Functional associations of genetic variants involved in the clinical manifestation of erythropoietic protoporphyria in the Argentinean population

Diagnosis and treatment of icteric hepatitis caused by erythropoietic protoporphyria: A case report

Erythropoietic protoporphyria (EPP) is a rare inherited disease caused by partial deficiency activity of the enzyme ferrochelatase (FECH), resulting in excessive accumulation of protoporphyrin IX in erythrocyte and tissues. Here, we report a patient with photosensitive dermatitis and acute icteric hepatitis caused by EPP, whose clinical and biochemical results successfully improved following 2-month treatment with glucose load, ursodeoxycholic acid capsules, and cholestyramine powder. This case provides a reference for a combination therapy strategy for patients with liver and skin injury caused by EPP.

Digital PCR (dPCR) analysis reveals that the homozygous c.315-48T>C variant in the FECH gene might cause erythropoietic protoporphyria (EPP)

Alterations in the ferrochelatase gene (FECH) are the basis of the phenotypic expressions in erythropoietic protoporphyria. The phenotype is due to the presence of a mutation in the FECH gene associated in trans to the c.315-48 T > C variant in the intron 3. The latter is able to increase the physiological quota of alternative splicing events in the intron 3. Other two variants in the FECH gene (c.1-252A > G and c.68-23C > T) have been found to be associated to the intron 3 variant in some populations and together, they constitute a haplotype (ACT/GTC), but eventually, their role in the alternative splicing event has never been elucidated. The absolute number of the aberrantly spliced FECH mRNA molecules and the absolute expression of the FECH gene were evaluated by digital PCR technique in a comprehensive cohort. The number of splicing events that rose in the presence of the c.315-48 T > C variant, both in the heterozygous and homozygous condition was reported for the first time. Also, the percentage of the inserted FECH mRNA increased, even doubled in the T/C cases, compared to T/T cases. The constant presence of variants in the promoter and intron 2 did not influence or modulate the aberrant splicing. The results of FECH gene expression suggested that the homozygosity for the c.315-48 T > C variant could be considered pathological. Thus, this study identified the homozygotes for the c.315-48 T > C variant as pathological. By extension, when the samples were categorised according to the haplotypes, the GTC haplotype in homozygosis was pathological.