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Porphyria Educational Services


PORPHYRIA EDUCATIONAL SERVICES BULLETIN
Vol. 1 No. 49                                              November 28, 1999
Focus:  Protoporphyria

            Protoporphyria which is also known as: erythrohepatic
porphyria, erythropoietic protoporphyria, HCP or proto, is one of the acute
hepatic porphyrias and is an inherited metabolic disease.

            Protoporphyria occurs in 10-20 per 100,000 individuals and is
autosomal dominant with variable expression which was not
recognized until 1961.

            In childhood cutaneous symptoms of the skin such as burning or
itching after light exposure occurs. Burning is often accompanied by
erythema and edema.

            Light through a window pane may evoke the symptoms. Chronic
lesions may occur which cause scarring and thickening of the skin on light
exposed areas.

            In Protoporphyria [HCP], liver disease is the other clinical
manifestation and can become severe in 10% of patients.

            Gallstones which are protoporphyrin rich may be present.
Laboratory findings.

            Also in laboratory studies,  mild microcytic hypochromic
 anemia occurs in 20-30% of the HCP patients.

            In HCP the bone marrow demonstrates a variable
percentage of erythropoietic precursor with red fluorescence.
The marrow morphology is otherwise normal.

            Protopophyria as a disorder results from a deficiency of the
ferrochelatase activity causing protoporphyrin to accumulate in excessive
levels in erythrocytes, bile, and feces but not urine.

             Increased erythrocyte protoporphyrin confirms the diagnosis. In
comparison to iron deficiency and lead poisoning, the increase erythrocyte
protoporphyrin is free and chelated to zinc.

            In regard to cutaneous findings of HCP, light exposed skin
biopsies may have an amorphous material staining positive for
periodic acid Schiff is found in and around capillary walls.

            Please note that this finding is not specific to protoporphyria
and has been reported in variegate porphyria and porphyria cutanea tarda.

            Liver biopsy specimens show portal inflammation and
fibrosis along with the deposition of a brown pigment.

             In 10% of patients severe liver disease develops and the livers
appear black and cirrhotic. When examined by polarization microscopy the
pigment deposits are birefringent and by electron microscopy demonstrate
crystals. The crystals are composed of protoporphyrin.

                For treatment of the cutaneous aspects of protoporphyria
clinicans try to increase tolerance to light through oral administration of beta
carotene. While the beta carotene may be useful, results may
not occur until 1-3 months after initiation of therapy.

                The only known side affect appears to be the yellow
discoloration to the skin.

                To reverse hepatic protoporphyrin accumulation
red blood cell transfusion  may be tried. The use of intravenous glucose is
effective in most acute attacks. If the glucose is slow to respond the use
of hematin administration may be tried which suppress excess protoporphyrin
production.

                An alternative is oral administration of cholestyramine or
activated charcoal to interrupt the intrahepatic circulation of
protoporphyrin. With the exception of liver disease development the
manifestations of the disease have a favorable prognosis and patients live a
normal lifespan.

[PDG 1999]