Iron Metabolism in Porphyria Cutanea Tarda and in Erythropoietic Protoporphyria

Absorption of radioiron, plasma iron and iron-binding capacity,plasma iron turnover and utilization of radioiron, tissue ironstores, and hepatic biopsy histology have been studied in 20patients with porphyria cutanea tarda (PCT). Some of these facetsof iron metabolism were also studied in five patients with erythropoieticprotoporphyria (EPP). Iron absorption was increased in nine untreated patients withPCT, particularly in those with cirrhosis, and was inappropriatelygreat in a further three. It was markedly increased in six patientswith PCT in remission many months after treatment by repeatedphlebotomy. Iron absorption was normal in two patients withEPP and raised in another in whom marrow storage iron was absent. Plasma iron was elevated in 15 of the patients with PCT, butin eight it fell into the normal range after their admissionto hospital, probably in part as a result of their stoppingtaking alcohol. Total iron-binding capacity was usually normal.Plasma iron turnover was mildly increased in seven of 20 patientswith PCT, and was normal in three with EPP. Utilization of radioironwas slightly reduced in two patients with PCT, and normal in14 others with PCT and in two with EPP. Liver biopsy in 18 untreatedpatients with PCT invariably showed evidence of liver damage,with excess iron in parenchymal cells, Kupffer cells, and, withone exception, portal tract macrophages. Repeat biopsy in fourpatients with PCT in remission after repeated phlebotomy showedabsence of stainable iron in three with normal liver architecture,and a marked reduction in excess iron in one with cirrhosis.Reticulo-endothelial iron was increased in marrow smears fromsix of 14 patients with PCT, and was absent in one and minimalin two patients with EPP. Storage iron mobilized by repeatedphlebotomy amounted to from 0.4 to 1.8 g in 12 patients withPCT. One patient with EPP had recurrent iron-deficiency anaemiaand in three others mobilizable storage iron was less than 250mg. The observations confirm the invariable finding of excess hepaticiron in PCT, with often a modest increase in mobilizable storageiron. The increase appears to be due to an inappropriately highlevel of iron absorption of uncertain cause. In contrast, suboptimalstorage iron may be frequent in EPP.     

The correlation between relatives under assortative mating for an X-linked and autosomal trait.

Correlations between various relatives are derived for phenotypic assortative mating at equilibrium for a trait determined by additive autosomal and X-linked loci without dominance, with proportional gene effects in the two sexes, and with an uncorrelated environment. It is assumed that genotype and environment are normally distributed, that phenotypes of mates are bivariate-normally distributed, and that regression of an individual's phenotype or genotype on the phenotype or genotype of any of his relatives is linear.     

Sclerosing cholangitis: CT findings

The value of computed tomography (CT) in the detection of primary sclerosing cholangitis (PSC) in the intrahepatic and extrahepatic biliary systems was assessed by comparing CT scans of 20 cases of PSC with cholangiographic findings. In 16 of 19 cases of extrahepatic duct disease demonstrated with cholangiography, CT demonstrated abnormalities of the common hepatic duct, or bile duct, including duct stenosis, mural nodularity, duct dilatation, wall thickening, and mural enhancement. CT demonstrated intrahepatic disease in all 20 cases, including duct dilatation, duct stenosis, pruning, and beading. CT was superior to cholangiography in characterization of the status of the intrahepatic duct system in 11 of 20 cases. In addition, CT demonstrated extrabiliary complications of PSC in 12 cases and superimposed cholangiocarcinoma in three cases. While cholangiography remains the standard for diagnosis and follow-up of PSC, CT can provide valuable information about the extent and complications of the disease.