1/6. Hypermethylation of the wild-type ferrochelatase allele is closely associated with severe liver complication in a family with erythropoietic protoporphyria.Erythropoietic protoporphyria (EPP) is an inherited disorder of heme biosynthesis caused by cellular decreases in ferrochelatase (FECH) activity. Clinical expression of this disorder usually requires coinheritance of a mutant FECH allele and a normal FECH allele expressed at a low level. In this study, we investigated the methylation status of a normal, but poorly expressed, FECH gene in a single Japanese family with EPP. In this family, the proband died from liver failure, whereas the mother and sister exhibited overt EPP with mild liver dysfunction. A splicing mutation (IVS9 1g-->a) in the FECH gene, which produces a mutant FECH transcript lacking exon 9, was detected in the maternal allele of the proband and his sister. All subjects, including the father, who did not exhibit EPP, possessed the IVS3-48c/c genotype. This allele increases the proportion of aberrantly spliced mRNA, resulting in reduced FECH activity. Normal FECH transcripts were, however, detected in the mother and sister, but not in the proband. The CpG sites in the region from bases -78 to -31 were partially methylated in the proband and his father, but not in his mother or sister. Additionally, CpG methylation within this region reduced transcription of the FECH gene. These results suggest that whereas the combination of a maternal IVS9 1a allele and a paternal IVS3-48c allele results in overt EPP, CpG methylation of the FECH gene promoter, likely inherited from the father, increases the severity of EPP, leading to fatal liver failure, as seen in the proband.- - - - - - - - - - ranking = 1keywords = family (Clic here for more details about this article) |
2/6. Autosomal recessive erythropoietic protoporphyria: a syndrome of severe photosensitivity and liver failure.Erythropoietic protoporphyria is caused by inherited deficiency of the haem synthetic enzyme ferrochelatase, and is characterized by lifelong photosensitivity. About 5% of patients also develop rapidly progressive liver failure. Inheritance is considered to be autosomal dominant, with transmission of a single ferrochelatase defect from one parent. We describe a family in which two siblings with protoporphyria suffered from severe photosensitivity and developed hepatic failure requiring liver transplantation. Their asymptomatic parents were heterozygous for distinct ferrochelatase gene mutations (exon 10 donor site a( 3)-->g and 1088T-->G). Both mutations disrupt splicing of the transcript and cause partial deficiency of ferrochelatase. The affected offspring were compound heterozygotes for these mutations. These patients suffered from an autosomal recessive form of protoporphyria characterized by severe photosensitivity and cholestatic liver disease in adolescence. We postulate that hepatic failure in erythropoietic protoporphyria may in some cases represent an autosomal recessive type of ferrochelatase deficiency distinct from the purely dermatological disorder. Studies of disease inheritance in families affected by protoporphyria may help identify those predisposed to develop severe liver complications, a distinction not currently possible.- - - - - - - - - - ranking = 0.16666666666667keywords = family (Clic here for more details about this article) |
3/6. Human ferrochelatase: a novel mutation in patients with erythropoietic protoporphyria and an isoform caused by alternative splicing.Erythropoietic protoporphyria (EPP), attributable to deficiency of ferrochelatase activity (FECH), is characterised mainly by cutaneous photosensitivity. To define the molecular defect in two EPP-affected siblings and their parents in a Swiss family, ferrochelatase cDNA was amplified by the polymerase chain reaction (PCR) and subjected to sequence analysis. A 5-bp deletion (T580-G584) was identified on one allele of the ferrochelatase gene in both patients and their mother. Screening of the mutation among family members of RsaI digestion of PCR-amplified genomic dna revealed autosomal dominant inheritance associated with abnormal protoporphyrin concentration and enzyme activity. We also isolated ferrochelatase cDNAs containing a 18-bp insertion (part of the intron 2 sequence) between exons 2 and 3; this corresponded to six extra amino acids (YESNIR) inserted between Arg-65 and Lys-66 of the known ferrochelatase. This isoform was identified initially in mRNAs derived from both alleles of the ferrochelatase gene in one patient. Its existence was confirmed in six additional EPP patients, in five out of seven controls, and in four different cell lines (fibroblast, muscle, hepatoma and myelogenous leukaemia). This isoform, roughly 20% of the total ferrochelatase mRNA, was generated through splicing at a second donor site in intron 2 and its presence was not linked to EPP.- - - - - - - - - - ranking = 0.33333333333333keywords = family (Clic here for more details about this article) |
4/6. Recessive inheritance of erythropoietic protoporphyria with liver failure.Erythropoietic protoporphyria is characterised by skin photosensitivity and deficiency of ferrochelatase; fatal liver disease occurs rarely. Transmission is considered to be dominant with incomplete penetrance. We investigated a family in which two siblings with erythropoietic protoporphyria developed hepatic failure that required transplantation. Their healthy parents had partial enzyme deficiency and were each heterozygous for a distinct mutation in a ferrochelatase gene. Both offspring were compound heterozygotes with ferrochelatase deficiency. Recessive transmission of protoporphyria predisposes to severe liver disease in this family. patients with the recessive form of this disease may be at special risk of hepatic failure.- - - - - - - - - - ranking = 0.33333333333333keywords = family (Clic here for more details about this article) |
5/6. Molecular defect in human erythropoietic protoporphyria with fatal liver failure.We investigated the molecular basis of ferrochelatase in a Japanese patient with erythropoietic protoporphyria (EPP), complicated by fatal liver failure, and defined a novel point mutation in the ferrochelatase gene. cDNAs were synthesized using Epstein-Barr-virus-transformed lymphoblastoid cells from the proband. cDNA clones encoding ferrochelatase in the proband were isolated by amplification using the polymerase chain reaction. There were two sizes of ferrochelatase cDNAs; one was normal in size, the other being smaller. sequence analysis of the abnormally sized cDNA clones revealed that they lacked exon 9 of the ferrochelatase gene. Genomic dna analysis demonstrated that the proband had the abnormal allele and that it contained a G to A point mutation at the first position of the donor site of intron 9. An identical mutation was detected in the affected family members of the proband by allele-specific oligonucleotide hybridization analysis. EPP is inherited in an autosomal dominant manner in this family.- - - - - - - - - - ranking = 0.33333333333333keywords = family (Clic here for more details about this article) |
6/6. Hepatoerythropoietic porphyria: relationship with familial porphyria cutanea tarda.Hepatoerythropoietic porphyria is characterized by an early beginning of severe photosensitivity, with an increase in urinary uroporphyrin excretion and other porphyrins, high isocoproporphyrin fecal levels and an accumulation of protoporphyrin in erythrocytes. It is caused by a dramatic decrease in the activity of the uroporphyrinogen decarboxylase. We report a clinical, biochemical and enzymatic study in a family, where a 2-year-old girl suffers from a hepatoerythropoietic porphyria, and the patient's maternal uncle from a porphyria cutanea tarda. We discuss the relationship between these diseases and their known mutations.- - - - - - - - - - ranking = 0.16666666666667keywords = family (Clic here for more details about this article) |