Brandhagen, David J.

Abstract Mutations in the hemojuvelin gene (HJV) are a cause of juvenile hemochromatosis (JH), but do they influence the phenotype of patients with adult-onset hemochromatosis with or without mutations of the HFE gene? We sequenced the coding region of the HJV gene of 133 subjects with primary iron overload (75 whites: 50 HFE, 25 non-HFE associated; 51 blacks: 1 HFE-associated; 7 Asians). A 63 year old white woman with non-HFE iron overload was found to be a compound heterozygote for HJV mutations: one previously identified (G320V); the other novel (C321W). The patient was diagnosed at age 30 (SI 223 μg/100 mL, TIBC 293 μg/100 mL, TS 76%, hepatic iron 31,154 μg/g, hepatic iron index 19.2). She had 2 healthy children, developed amenorrhea at age 23, had a history of hypothyroidism and developed Type 2 diabetes at age 59. She was iron depleted after 66 phlebotomies. Among 74 other white subjects with iron overload we found 3 polymorphisms: IVS2-6 C>G (3 subjects); nt 165 T>A (G55G), and IVS4-50 C>T (1 subject, each). Among 51 black iron overloaded and 132 black control subjects, the most notable polymorphism was a DNA triplet insert predicting an insertion of glycine. This was found in 2 subjects, one with and one without iron storage disease. Among the iron overloaded black subjects, we also found IVS2-6 C>G (1 subject), nt -140 G>C (3 subjects), nt 792 G>C (S264S) (1 subject), nt 828 C>A (I275I) (1 subject), and nt 929 C>G (A310G) (2 subjects). These polymorphisms, excluding S264S and I275I, were found in control subjects as well. No coding region mutations or polymorphisms were found in the 7 Asian iron overloaded subjects. We also determined the gene frequency of the HJV I222N and G320V mutations in adult control subjects from central Alabama, where a JH index case had been found with these mutations. Allele frequencies of I222N and G320V were 0.002 (n=240) and 0 (n=241) respectively in control whites. A white control female heterozygous for the I222N was also heterozygous for HFE C282Y but had normal iron measures. No I222N and G320V mutations were found in 124 and 118 black subjects respectively. We conclude that: 1) iron overloaded patients without HFE mutations, with or without a JH phenotype should be screened for HJV; 2) HJV mutations do not account for most cases of increased penetrance of HFE-associated hemochromatosis; 3) double heterozygosity for HFE C282Y and HJV I222N does not necessarily cause iron overload.

Hypophosphatemia has been described in patients undergoing right hepatectomy for liver cancer and in living donors for liver transplantation who also received total parenteral nutrition. At the study centre, significant hypophosphatemia (0.36 mmol/L or less) requiring intravenous replacement was seen in two of the first nine living donors for adult-to-adult liver transplantation. To determine the frequency of hypophosphatemia in living donors, the authors obtained phosphate levels on stored serum samples from postoperative days 0, 1, 3 and 7 in all nine patients, none of whom were on total parenteral nutrition. Within the first week, hypophosphatemia developed in 55.6% of patients and phosphate levels returned to normal by day 7 in all nine patients. One patient had normal phosphate levels during the first week, but had profound hypophosphatemia (0.32 mmol/L) on day 14 when he presented with a Staphylococcus aureus infection of a bile collection and significant hypoxemia. The extent of hepatectomy and the rate of liver regeneration, estimated by baseline and postoperative day 7 volumetric computed tomography scans, did not correlate with the development of hypophosphatemia. In conclusion, hypophosphatemia is common in living donors undergoing right hepatectomy and may be associated with complications. All living donors should be monitored for the development of hypophosphatemia during the first two postoperative weeks.