Comprehensive hereditary hemochromatosis genotyping

Hereditary hemochromatosis (HH) is an iron-overload disease common in populations of Northern European origin. Patients display increased iron absorption leading to excessive iron deposition and potential multiorgan failure. Using polymerase chain reaction sequence-specific primer (PCR-SSP) technology, we have developed an HH diagnosis assay capable of detecting 19 non-synonymous HFE mutations (including a previously unreported mutation, V295A) and several TFR2, SLC11A3 and H ferritin alleles implicated in HH. As part of the validation process, 159 UK renal donors were genotyped to determine HH allele frequencies in the UK population. The alleles nominally identified as HFE*01 (C282Y), HFE*02 (H63D) and HFE*03 (S65C) were found at frequencies of 0.085, 0.173 and 0.009, respectively. All other potential HH-associated alleles were absent, confirming their low prevalence in this population. This assay enables comprehensive routine HH genotyping, producing rapid, accurate and reproducible results at low cost.     

New insights in the pathogenesis of immunoglobulin A vasculitis (Henoch-Schönlein purpura)

Immunoglobulin A vasculitis (IgAV), also referred to as Henoch-Schönlein purpura, is the most common form of childhood vasculitis. The pathogenesis of IgAV is still largely unknown. The disease is characterized by IgA1-immune deposits, complement factors and neutrophil infiltration, which is accompanied with vascular inflammation. Incidence of IgAV is twice as high during fall and winter, suggesting an environmental trigger associated to climate. Symptoms can resolve without intervention, but some patients develop glomerulonephritis with features similar to IgA nephropathy that include hematuria, proteinuria and IgA deposition in the glomerulus. Ultimately, this can lead to end-stage renal disease. In IgA nephropathy immune complexes containing galactose-deficient (Gd-)IgA1 are found and thought to play a role in pathogenesis. Although Gd-IgA1 complexes are also present in patients with IgAV with nephritis, their role in IgAV is disputed. Alternatively, it has been proposed that in IgAV IgA1 antibodies are generated against endothelial cells. We anticipate that such IgA complexes can activate neutrophils via the IgA Fc receptor FcαRI (CD89), thereby inducing neutrophil migration and activation, which ultimately causes tissue damage in IgAV. In this Review, we discuss the putative role of IgA, IgA receptors, neutrophils and other factors such as infections, genetics and the complement system in the pathogenesis of IgA vasculitis.     

Tumor volume to fetal weight ratio as an early prognostic classification for fetal sacrococcygeal teratoma

Purpose

This study was designed to develop a prognostic factor for fetuses with sacrococcygeal teratoma (SCT) that may be useful to predict outcome and guide counseling early in pregnancy. We hypothesize that, in fetuses with SCT, the ratio of tumor size to estimated fetal weight in the second trimester predicts outcome.

Methods

We retrospectively reviewed charts of all patients evaluated at our Fetal Center for SCT between 2004 and 2009. Estimated fetal weight and tumor volume were calculated based on prenatal ultrasound or fetal magnetic resonance imaging. Patients were stratified based on tumor volume to fetal weight ratio (TFR), and their outcomes were analyzed by Fisher's Exact test.

Results

Tumor volume to fetal weight ratio before 24 weeks' gestation was predictive of outcome. Those with a TFR less than or equal to 0.12 (n = 5) had a significantly better outcome than patients with a TFR greater than 0.12 (n = 5, P < .05). All patients with poor outcomes had a TFR greater than 0.12 by 24 weeks' gestation. A TFR greater than 0.12 predicted poor outcome with 100% sensitivity and 83% specificity. All 4 patients who developed hydrops had a TFR greater than 0.12.

Conclusion

In our series of fetuses with SCT, TFR before 24 weeks' gestation correlates with outcome. This novel, prenatal diagnostic tool may be useful in prenatal counseling and for early identification of high-risk fetuses.     

High prevalence of HFE gene mutations in patients with porphyria cutanea tarda in the Czech Republic

Background  Iron overload and hepatitis C virus (HCV) infection are independent factors which are thought to play a role in the pathogenesis of porphyria cutanea tarda (PCT).
Objectives  To determine the prevalence of the HFE gene mutations p.Cys282Tyr (C282Y), p.His63Asp (H63D) and p.Ser65Cys (S65C), the p.Tyr250X (Y250X) mutation of the TFR2 gene, and HCV infection in patients with PCT in the Czech population, and to make comparison of the iron status among the respective genotypes.
Methods  Iron metabolism indices, results of mutational analysis and serological markers of HCV infection were examined in 63 patients with PCT.
Results  The HFE gene mutations were detected in 70% of patients with PCT compared with 35% in the control group ( P  <   0·001). Mean serum ferritin levels were increased in all genotypes, the highest being in homozygotes for the p.Cys282Tyr mutation. HCV infection was detected in only 8% of patients with PCT.
Conclusions  There was a very high prevalence of the p.Cys282Tyr and p.His63Asp mutations observed in patients with PCT accompanied by mild degrees of iron overload, which was genotype dependent.     

紫外线诱导HaCat转铁蛋白受体表达机制的初步探讨

目的探讨紫外线诱导转铁蛋白受体(TFR)表达的机制。方法以紫外线(UVB)照射HaCat,流式细胞仪检测TFR的表达,realtime-PCR检测TFRmRNA表达。结果UVB可增强TFR的表达,并呈剂量依赖性和时间依赖性。10mJ/cm2的UVB就能促进TFR表达,在紫外线照射后6h开始表达。UVB以剂量依赖性方式诱导TFR的mRNA表达,在UVB照射后8h,TFRmRNA表达水平达高峰,16h开始下降。结论UVB可增强TFR的表达。     

何首乌提取物对人乳腺癌细胞脂肪酸合酶的抑制研究

目的 研究何首乌提取物对人乳腺癌MCF7细胞脂肪酸合酶(fatty acid synthase，FAS)的抑制作用。方法 MTT法测定人乳腺癌MCF7细胞增殖速度，采用超速离心技术部分纯化人乳腺癌MCF7细胞FAS。不同浓度何首乌提取物与FAS相互作用不同时间后，加入底物，用分光光度法观察何首鸟提取物对FAS的抑制作用。结果 何首鸟提取物对人乳腺癌MCF7细胞的增殖有一定的抑制作用。人乳腺癌MCF7细胞FAS被部分纯化，三种浓度何首乌提取物(0．1，0．5，1g／L)与FAS在催化前相互作用0、5和10min，对FAS活性的抑制率分别为24．60％、27．30％、and42．75％(0．1g／L)；43．50％、50．30％、and94．03％(O．5g／L)；98．60％、97．30％ and97．05％(1g／L)。结论 何首乌提取物对人乳腺癌MCF7细胞FAS具有抑制作用；作用强度既依赖于抑制剂浓度，又依赖于抑制剂与酶相互作用时间。     

映山红花总黄酮对盐酸异丙肾上腺素诱导大鼠心肌缺血的保护作用

目的观察映山红花总黄酮(TFR)对盐酸异丙肾上腺素诱导的实验性心肌缺血的保护作用。方法采用皮下(sc)注射盐酸异丙肾上腺素(Iso)(8 mg.kg-1×2 d)诱导大鼠实验性心肌缺血模型,测定血清中MDA含量、GSH-PX活力、SOD及心肌组织中ATPase活性。同时行心肌组织病理组织学检查。结果TFR 30 mg.kg-1显著降低血清中MDA的生成,30,15 mg.kg-1及60,30 mg.kg-1升高SOD,GSH-PX的活力,60,30 mg.kg-1TFR可抑制心肌组织中Na -K -ATPase,Ca2 -Mg2 -AT-Pase,总ATPase活力的降低,TFR 60,30 mg.kg-1能显著改善sc Iso后心肌病理损伤程度,降低其病理损伤评分。结论TFR对盐酸异丙肾上腺素诱导的实验性心肌缺血有保护作用,其机制可能与减少体内自由基生成、改善心肌能量代谢有关。     

Clinical and pathologic findings in hemochromatosis type 3 due to a novel mutation in transferrin receptor 2 gene

BACKGROUND & AIMS: Although most patients with hereditary hemochromatosis are homozygous for a single mutation of the HFE gene on chromosome 6p, accumulating evidence indicates that the disease is genetically heterogeneous. Type 3 hemochromatosis, recently described in 4 families, is linked to mutations of the gene encoding transferrin receptor 2 on chromosome 7q22. Here we report data from a family carrying a new mutation of the transferrin receptor 2 gene. METHODS: Detailed clinical and histopathologic documentation was available for most family members. The entire coding sequence and exon/intron boundaries of the transferrin receptor 2 gene were analyzed by direct sequencing. RESULTS: A 12-nucleotide deletion in exon 16, causing the loss of 4 amino acids (AVAQ 594-597 del), was detected at the homozygous state in the 3 patients with histologically proven iron overload. The deletion segregated with the disease within the family and was not found in 100 healthy controls. Some clinical and pathologic characteristics, such as low penetrance in the premenopausal woman, and early iron deposition in periportal hepatocytes resembled those of classic, HFE-related hemochromatosis. CONCLUSIONS: Our data support the role of the transferrin receptor 2 gene in hemochromatosis type 3 as well as its critical involvement in the maintenance of iron homeostasis in humans.