1例携带HFE基因剪切突变的遗传性血色病患者家系调查

目的探讨1例新型的遗传性血色病(HH)患者家系HFE基因突变形式。方法对确诊的1例HH患者分析其与5位相关亲属的血色病基因,提取血液基因组DNA,采用PCR扩增相关基因HFE、HJV、HAMP、转铁蛋白受体(TfR)2、SLC40A1的外显子、内含子剪切序列,琼脂糖凝胶电泳、纯化后,双向直接测序检测突变位点。结果先证者肝功能异常,血清铁(SI)、总铁结合力(TIBC)、铁蛋白(SF)、转铁蛋白饱和度(TS)均升高,HFE基因外显子EXON2的区间序列2号内含子第4个碱基出现T→C纯合突变(IVs 2+4T→C,C/C纯合,splicing,异常),HJV、HAMP、TfR2、SLC40A1未见异常,患者儿子出现与其相同纯合突变,3位亲属存在杂合突变,1位亲属无异常突变。结论基因检测在血色病诊断中起着重要作用,HFE基因IVs 2+4T→C突变可能是新型的中国HH的致病遗传基因突变类型。     

遗传性血色病五例临床分析

目的探讨遗传性血色病的临床特点,评价铁生化指标、MRI、肝穿病理学检查在遗传性血色病诊断中的作用。方法5例患者,4男1女。先证者因不明原因肝硬化伴皮肤黏膜色素沉着来院确诊。通过对先证者的家系调查,进行临床、铁生化指标、胸腹部MRI、病理组织学和特殊染色的观察,确诊4例早期患者。结果该家系5例患者中3例出现皮肤黏膜色素沉着,1例肝硬化,未见糖尿病;5例患者血清铁均正常,其中3例血清铁蛋白异常;2例肝穿病理检查,其中1例肝铁过多沉积;而MRI显示每例患者至少有1个内脏器官的铁沉积,以肝脏铁沉积最为显著。结论遗传性血色病患者在我国较少见,临床特点不明显,诊断困难,尤其是遗传性血色病早期患者。家系调查结合MRI检测对遗传性血色病的早期诊断显得更为重要。     

遗传性血色病分子机制的研究进展

遗传性血色病是由于基因变异引起铁代谢异常,进而造成多器官铁沉积.目前认为铁代谢转运主要由hepcidin-转铁蛋白(FPN)轴控制,血色病蛋白编码基因(HFE)、FPN受体2(TfR2)、血幼素(HJV)、HAMP(hepcidin的编码基因)基因突变都可以影响hepcidin水平.FPN突变也可引起铁超负荷,但机制有所不同.各调节蛋白的基因突变可引起不同的疾病表型.     

家族性肥厚型心肌病MYBPC3基因变异及其临床表型分析

目的:分析家族性肥厚型心肌病(FHCM)患者心脏肌球蛋白结合蛋白C3(MYBPC3)基因变异及其与临床表型的关系。方法:纳入2016—2018年于福建省立医院就诊的肥厚型心肌病(HCM)10个家系,通过二代测序筛选出携带MYBPC3基因变异的3个家系,收集家系中携带MYBPC3基因变异患者的临床资料,包括家族史、临床表现、心电图及超声心动图,以进行基因型-表型关联分析。结果:3个家系共有19名家系成员,有2名家系成员猝死,8名家系成员携带有MYBPC3基因变异。其中两个家系携带MYBPC3基因c.3624delC杂合缺失变异;1个家系携带MYBPC3基因c.3369_3370insC变异,该家系其他家系成员携带ACTN2、CACNA1C、DTNA、TTN基因变异。在这3个家系中,4例患者在40岁以前发病,其中1例患者23岁时猝死;3例患者以室间隔增厚为主,合并左室流出道梗阻,4例患者室间隔及左室壁均有增厚但程度较轻,无左室流出道梗阻;1例患者合并心房颤动,2例患者有室性期前收缩。结论:MYBPC3基因不同位点的突变可导致FHCM,同一家族的HCM患者可能有不同的基因变异位点。MYBPC3基因c.3369_3370insC变异为首次发现的致病基因变异。与以前的报道不同,本研究发现有MYBPC3基因变异的HCM患者发病早,病情进展快,临床预后差。     

我国人群遗传性血色病基因突变特点分析

目的分析我国人群遗传性血色病(HH)的基因突变特点。方法选取2013年1月-2015年12月就诊于首都医科大学附属北京友谊医院的9例HH患者,提取基因组DNA,对4种类型HH基因HFE(Ⅰ型)、HJV(ⅡA型)、HAMP(ⅡB型)、TFR2(Ⅲ型)及SLC40A1(Ⅳ型)所有外显子进行PCR扩增和Sanger测序,分析基因突变情况;另选取50例健康人群作为对照组,分析已鉴定的基因突变在健康人群中的表达情况。结果 9例HH患者中,存在Ⅰ型HFE基因H63D突变2例、ⅡA型HJV基因E3D突变1例、Ⅲ型TFR2基因I238M突变2例,Ⅳ型SLC40A1基因IVS 3+10 del GTT剪切突变1例,未检出欧美人群常见的Ⅰ型HFE C282Y突变。5例患者未检测出任何错义或剪切突变。此外,在一个遗传家系中发现HH患者同时存在HFE H63D、HJV E3D及TFR2I238M突变,但携带其中2个突变的健康兄妹没有出现HH表型。结论 HH基因突变在不同种族患者中存在较大的差异,我国可能以非HFE型HH为主,推测可能存在与目前已知基因不同的HH相关基因,需进一步研究证实。     

内啡肽基因变异所致遗传性出血性毛细血管扩张症家系的遗传学分析

目的探讨ENG基因变异所致遗传性出血性毛细血管扩张症(hereditary hemorrhagic telangiectasia, HHT)一家系的遗传学特征。方法选取在大理大学第一附属医院就诊的一个HHT家系3代共17人为研究对象。收集该HHT家系先证者的临床资料及家系患病情况。应用全外显子组测序技术对先证者进行疑似致病基因筛选, 应用Sanger测序进行家系验证。结果先证者及母亲有反复鼻出血、皮肤黏膜毛细血管扩张表现, 先证者及其母亲、女儿和表弟胸部增强CT提示存在不同程度的肺动静脉畸形。全外显子测序结果显示先证者携带ENG基因c.579₅99del非移码缺失突变, Sanger测序显示其母亲、女儿和表弟携带相同的变异。结论 ENG基因c.579₅99del突变可能是导致该家系HHT的遗传学基础。     

探讨Ⅳ型遗传性血色病肝脏hepcidin mRNA表达及意义

目的探讨Ⅳ型遗传性血色病肝脏hepcidin mRNA表达及临床意义。方法对一例遗传性血色病先证者的家系进行遗传学问询,病史采集,体格检查,实验室检查,MRI检查及肝脏组织病理学检查,运用实时荧光定量PCR法检测肝脏hepcidin mRNA表达,并进行遗传性血色病发病相关基因的基因筛查。结果该家系15人有7例经MRI证实存在不同程度实质脏器铁沉积,3例接受肝活检者中的2例肝脏组织普鲁士蓝染色证实铁沉积,实时荧光定量PCR法检测显示肝脏hepcidin mRNA表达上调,外周静脉血基因筛查发现2q32的SLC40A1六号外显子有一处碱基发生点突变,即T173C。结论1.本家系罹患Ⅳ型遗传性血色病,遗传学特征为常染色体显性遗传,SLC40A1六号外显子有一处点突变,但该突变与国际上先前报道的突变位点并不相符,说明该基因突变可能是新的突变类型;2.本家系肝脏hepcidin mRNA表达上调,提示血清hepcidin水平升高,说明可能存在hepcidin抵抗现象,使机体对hepcidin负性调节低反应,从而导致铁代谢紊乱出现铁沉积并出现脏器功能损害。     

十个汉族家族性肥厚型心肌病MYH7、MYBPC3和TNNT2基因筛查结果及相应的临床特征

目的研究10个汉族家族性肥厚型心肌病的致病基因及突变特点,分析基因型与临床表型的相互关系。方法对10个无血缘关系的汉族家族性肥厚型心肌病的家系的MYH7基因、MYBPC3基因和TNNT2基因进行扫描,聚合酶链式反应扩增其外显子及剪接部位基因组DNA片段,直接测序分析,并分析各突变患者相应临床表型特点。结果10个汉族家族性肥厚型心肌病的家系中5个家系发现上述基因突变,3个家系MYH7基因发生错义突变,分别为Arg663His、Glu924Lys和Ile736Thr,Glu924Lya在中国患者中首次发现。这3个家系中3例患者猝死;2个家系MYBPC3基因发生错义突变、剪接突变和移码突变,1个家系先证者为复合突变即18外显子错义突变ArgS02Trp及27外显子剪接突变即IVS27＋12C〉T,先证者之母携带错义突变,先证者之父携带剪接突变;在另一家系首次发现Gly347fa移码突变,该家系中1例猝死。10个家系中未发现TNNT2基因的功能区突变,但在内含子3中发现一个STR多态性即CTTCT5个碱基的插入／缺失,7个家系先证者发现D基因型。结论MYH7基因为中国汉族家族性肥厚型心肌病最常见致病基因,临床表现较重,猝死率较高。MYBPC3突变也较常见,症状较轻,发病较晚,但复合突变发病早、症状重。同一突变的临床表型存在异质性提示多因素参与了肥厚型心肌病的发生与发展。     

肥厚型心肌病家系携带ACTN2、MYBPC3和TNNI3基因突变分析

目的:对收集的1例肥厚型心肌病家系的致病基因进行突变位点分析,阐明基因型与临床表型的关系。方法:利用目标外显子捕获技术和二代测序技术对先证者的与肥厚型心肌病有关的基因进行基因突变筛查,并使用Sanger测序法验证可疑突变位点,同时筛查患者家系成员4例和健康人100例,确定该家系患者的致病突变,并利用SIFT、Polyphen2和MutationTaster这3种软件进行突变基因功能检测。结果:该家系除先证者外,4例有血缘关系的研究对象中3例携带ACTN2基因c.1162TA错义突变(p.Trp388Arg),2例携带MYBPC3基因c.472GA错义突变(p.Val158Met),2例携带TNNI3基因c.235CT错义突变(p.Arg79Cys)。该家系的先证者同时携带上述3种突变基因。3种预测软件预测这3种突变均为有害突变。结论:在该患者家系中发现的基因突变位点可能是肥厚型心肌病的致病突变,携带多种突变的家系成员更易发生肥厚型心肌病,但其确切发病机制仍需进一步研究。     

一个遗传性血色病家系的临床特点及其遗传基础初探

目的 探讨一个遗传性血色病家系的临床特点及初步查找该家系的遗传基础. 方法对该家系成员进行问诊、体检、实验室检查、多器官MRI检查、肝穿刺活组织检查(铁染色),绘制家系图谱.采集血样,对常见的遗传性血色病致病基因进行测序分析. 结果该家系成员中有7人存在铁过载,临床诊断为遗传性血色病.家系患者代代相传,无性别差异,外显率约46%.常见的SLC40A1和HFE基因突变位点在该家系成员中未发现. 结论该遗传性血色病家系患者以皮肤色素沉着、肝脾等脏器铁沉积最具特征,为常染色体显性遗传,但其遗传基础尚不明确.     

Hepatic iron metabolism gene expression profiles in HFE associated hereditary hemochromatosis

BACKGROUND: Individuals with pathogenic mutations in HFE, hemojuvelin (HJV) and transferrin receptor 2 (TfR2) have low levels of hepcidin, but little is known about the hepatic expression of these molecules in patients with physiological iron overload or HFE associated Hemochromatosis (HH). AIMS: To examine the hepatic mRNA expression of iron homeostasis genes in patients with HH, physiological iron overload and healthy controls. PATIENTS: Untreated C282Y homozygous HH patients (n=20) with elevated serum ferritin (SF) and patients with physiological iron overload (n=12) with positive hepatocellular iron staining and negative HFE mutation analysis were evaluated. The control cohort (n=10) had normal iron parameters, negative HFE mutation analysis and negative hepatocellular iron staining. METHODS: Hepcidin, HJV (hemojuvelin), TfR2 (transferrin receptor 2), HFE, IL6 (interleukin 6) and ferroportin mRNA expression patterns were evaluated using quantitative real-time PCR. RESULTS: Physiological iron overload led to significantly upregulated hepcidin, HJV and ferroportin mRNA expression while TfR2 expression was not significantly different to controls. In contrast, HFE associated iron overload failed to induce hepcidin or HJV. TfR2 mRNA expression was significantly reduced when compared to controls. Ferroportin expression in HH was comparable to that found in physiological iron overload. Neither HFE nor IL6 expression was altered by variation in iron status. CONCLUSIONS: These findings suggest that patients with HH, in contrast to those with physiological iron overload, have a weakened TfR2 sensing mechanism that leads to the lack of induction of hepcidin and HJV. The C282Y HFE mutation does not appear to impede the hepatocellular iron export function of ferroportin.     

High prevalence of a screening-detected,HFE-unrelated,mild idiopathic iron overload in Northern Italy

BACKGROUND AND OBJECTIVES: In Italy, typical HFE mutations account for only 64% of the cases with overt hereditary hemochromatosis (HH), and a common HFE-unrelated disease was hypothesized. DESIGN AND METHODS: One thousand and fifty potential blood donors were screened by iron tests, C282Y and H63D HFE mutation analysis in a region in North Italy. Subjects with repeated fasting transferrin saturation of 45% or more and no secondary iron overload were defined as probands with idiopathic iron overload. To assess the inheritance of iron overload, relatives of probands were screened. RESULTS: The overall frequency of probands with idiopathic iron overload was 3.43% (95% confidence interval, 2.32 to 4.52). Of these, 8.4% had genotypes associated with HH (compound heterozygous for H63D/C282Y or homozygous for H63D HFE mutations), and 91.6% had atypical genotypes: 47.2% were heterozygous for C282Y or H63D HFE mutations, and 44.4% had wild type/wild type genotype. A family history of iron overload was proven in 33.3% of probands with atypical genotypes (1.04% of the overall population). Pedigree analysis excluded linkage of heterozygous HFE mutations with iron overload (cumulative lod score 2.41) and documented a recessive non-HLA-linked locus accounting for iron overload in wild type/wild type genotypes. None of the probands had clinical signs of iron accumulation; in males, serum ferritin positively correlated with age (r=0.63, p<0.01), and the regression model predicted a serum ferritin of 700 ng/mL at the age of 58. INTERPRETATION AND CONCLUSIONS: In Northern Italy an HFE-unrelated, mild idiopathic iron overload is highly prevalent. A recessive locus accounts for iron overload in at least 1.04% of the overall population.     

Juvenile hemochromatosis associated with heterozygosity for novel hemojuvelin mutations and with unknown cofactors

Background & Aims. Juvenile hemochromatosis (JH) is a rare autosomal recessive disorder characterized by severe early-onset iron overload, caused by mutations in hemojuvelin (HJV), hepcidin (HAMP), or a combination of genes regulating iron metabolism. Here we describe two JH cases associated with simple heterozygosity for novel HJV mutations and unknown genetic factors. Case 1: A 12 year-old male from Central Italy with beta-thalassemia trait, increased aminotransferases, ferritin 9035 ng/ml and transferrin saturation 84%, massive hepatocellular siderosis and hepatic bridging fibrosis. Case 2: A 12 year-old female from Northern Italy with ferritin 467 ng/ml, transferrin saturation 87-95%, and moderate hepatic iron overload.Material and methods. Direct sequencing of hemochromatosis genes (HFE-TfR2-HJV-HAMP-FPN-1) was performed in the children and siblings.Results. In case 1, we detected heterozygosity for a novel HJV mutation (g.3659_3660insG), which was inherited together with the beta thalassemia trait from the father, who (as well as the mother) had normal iron parameters. In case 2, we detected another novel HJV mutation (g.2297delC) in heterozygosity, which was inherited from the mother, affected by mild iron deficiency. The father had normal iron stores. Both mutations are frameshifts determining premature stop codons. No other disease causing variant was detected.Conclusion. Although beta-thalassemia trait was a possible cofactor of iron overload in case 1, iron overload cannot be explained by simple heterozygosity for HJV mutations in both cases. Other genetic factors should be investigated, and further studies are needed to understand genotype-phenotype correlations in JH.     

Iron overload disease: recent findings

Iron overload diseases are due to a progressive increase in total body iron stores that leads to deposition of iron in parenchymal organs and to subsequent damage to these organs. The commonest inherited form of iron overload is hereditary hemochromatosis (HH), an autosomal recessive disorder affecting the white population. Although in the western world and in northern Europe the majority of cases of HH are associated with an HFE gene mutation (C282Y and H63D), there are families with a familial iron overload disorder in whom neither the C282Y nor the H63D mutations were found. Recently, other forms of HH that are not related to HFE, but are due to mutations in genes coding iron transport proteins (ferroportin-1, TfR2, hepcidin) have been described. The clinical presentation of the disorder is highly variable, depending on the severity of iron overload. In fact, the inappropriate absorption and deposition of dietary iron may result in the development of hepatic and non-hepatic end-organ injury, leading to liver cirrhosis, hepatocellular carcinoma, diabetes, arthritis, skin pigmentation and cardiac diseases. HH and its sequelae are preventable with an early diagnosis and treatment. Patients with evidence of iron overload, a family history of HH or other risk factors should be screened by genotype testing for the HFE mutation. Nowadays, HH is recognized as being a complex genetic disease with probable significant environmental and genetic modifying factors, such as hepatitis C virus infection and alcohol abuse, and it has been shown that HFE mutations represent an independent risk factor for fibrosis and cirrhosis in chronic hepatitis C.     

Down-regulation of hepcidin in porphyria cutanea tarda

Hepatic siderosis is common in patients with porphyria cutanea tarda (PCT). Mutations in the hereditary hemochromatosis (hh) gene (HFE) explain the siderosis in approximately 20% patients, suggesting that the remaining occurrences result from additional genetic and environmental factors. Two genes known to modify iron loading in hh are hepcidin (HAMP) and hemojuvelin (HJV). To determine if mutations in or expression of these genes influenced iron overload in PCT, we compared sequences of HAMP and HJV in 96 patients with PCT and 88 HFE C282Y homozygotes with marked hepatic iron overload. We also compared hepatic expression of these and other iron-related genes in a group of patients with PCT and hh. Two intronic polymorphisms in HJV were associated with elevated serum ferritin in HFE C282Y homozygotes. No exonic polymorphisms were identified. Sequencing of HAMP revealed exonic polymorphisms in 2 patients with PCT: heterozygosity for a G-->A transition (G71D substitution) in one and heterozygosity for an A-->G transition (K83R substitution) in the other. Hepatic HAMP expression in patients with PCT was significantly reduced, regardless of HFE genotype, when compared with patients with hh but without PCT with comparable iron overload. These data indicate that the hepatic siderosis associated with PCT likely results from dysregulated HAMP.     

Genetic background of primary iron overload syndromes in Japan

The different prevalences of iron overload syndromes between Caucasians and Asians may be accounted for by the differences in genetic background. The major mutation of hemochromatosis in Celtic ancestry, C282Y of HFE, was reported in a Japanese patient. Five patients of 3 families with the hepatic transferrin receptor gene (TFR2)-linked hemochromatosis were found in different areas of Japan, suggesting that TFR2 is a major gene in Japanese people. Three patients with mutations in the hemojuvelin gene, HJV, showed also middle-age-onset hemochromatosis. A heterozygous mutation in the H ferritin gene, FTH1, was found in a family of 3 affected patients. Another autosomal dominant SLC40A1-linked hyperferritinemia (ferroportin disease) was found in 3 patients of 2 families. Two patients with hemochromatosis were free from any mutations in the genes investigated. In conclusion, the genetic backgrounds of Japanese patients with primary iron overload syndromes were partially clarified, showing some phenotype-genotype correlations.     

Iron overload and prolonged ingestion of iron supplements: clinical features and mutation analysis of hemochromatosis-associated genes in four cases

We evaluated and treated four white adults (one man, three women) who had iron overload associated with daily ingestion of iron supplements for 7, 15, 35, and 61 years, respectively. We performed HFE mutation analysis to detect C282Y, H63D, and S65C in each patient; in two patients, HFE exons were sequenced. In two patients, direct sequencing was performed to detect coding region mutations of TFR2, HAMP, FPN1, HJV, and ALAS2. Patients 1-4 ingested 153, 547, 1,341, and 4,898 g of inorganic iron as supplements. Patient 1 had hemochromatosis, HFE C282Y homozygosity, and beta-thalassemia minor. Patient 2 had spherocytosis and no HFE coding region mutations. Patient 3 had no anemia, a normal HFE genotype, and no coding region mutations in HAMP, FPN1, HJV, or ALAS2; she was heterozygous for the TFR2 coding region mutation V583I (nt 1,747 G-->A, exon 15). Patient 4 had no anemia and no coding region mutations in HFE, TFR2, HAMP, FPN1, HJV, or ALAS2. Iron removed by phlebotomy was 32.4, 10.4, 15.2, and 4.0 g, respectively. There was a positive correlation of log(10) serum ferritin and the quantity of iron removed by phlebotomy (P = 0.0371). Estimated absorption of iron from supplements in patients 1-4 was 20.9%, 1.9%, 1.1%, and 0.08%. We conclude that the clinical phenotypes and hemochromatosis genotypes of adults who develop iron overload after ingesting iron supplements over long periods are heterogeneous. Therapeutic phlebotomy is feasible and effective, and would prevent complications of iron overload.     

Mutations of the HFE gene among Turkish hereditary hemochromatosis patients

Since the discovery of the HFE gene, C282Y and H63D mutations have been reported as significantly correlated with clinically manifested hereditary hemochromatosis (HH). As the other genes involved in iron metabolism have been described, non-HFE cases of HH have been identified. Since in the general Turkish population, the C282Y mutation is not found and the H63D mutation is of high frequency, we aimed to determine mutations in the HFE genes in our patients with HH. The HFE gene of the five patients with HH were sequenced. C282Y mutation was absent, and all HH patients were heterozygote for H63D mutation. No other mutation was found in HFE gene by sequencing. Although the higher allele frequency of the H63D mutation in Turkish HH patients than in the general population implies a role of the H63D mutation in iron overload, there is a strong possibility that Turkish HH patients have non-HFE hemochromatosis.     

Survival after liver transplantation in patients with hepatic iron overload: the national hemochromatosis transplant registry

BACKGROUND & AIMS: Previous uncontrolled studies have suggested that patients with hepatic iron overload have a poor outcome after liver transplantation. We examined the effect of HFE mutations on posttransplantation survival in patients with hepatic iron overload. METHODS: Two hundred sixty patients with end-stage liver disease and hepatic iron overload were enrolled from 12 liver transplantation centers. Hepatic iron concentration (HIC), hepatic iron index (HII), HFE mutation status, and survival after liver transplantation were recorded. RESULTS: HFE-associated hemochromatosis (HH) defined as homozygosity for the C282Y (n = 14, 7.2%) mutation or compound heterozygosity for the C282Y/H63D (n = 11, 5.6%) mutation was identified in 12.8% of patients. Survival postliver transplantation was significantly lower among patients with HH (1-, 3-, and 5-year survival rates of 64%, 48%, 34%, respectively) compared with simple heterozygotes (C282Y/wt or H63D/wt) or wild-type patients. Patients with HH had a hazard ratio for death of 2.6 (P = .002) after adjustment for age, United Network for Organ Sharing status, year of transplantation, and either elevated HII or HIC. Non-HH patients with hepatic iron overload also had significantly decreased survival when compared with the overall population undergoing liver transplantation (OR = 1.4, 95% CI: 1.15-1.61, P < .001). CONCLUSIONS: One- and 5-year survivals after liver transplantation are significantly lower among patients with HFE-associated HH. Our data also suggest that hepatic iron overload may be associated with decreased survival after liver transplantation, even in patients without HH. Early diagnosis of hepatic iron overload using HFE gene testing and iron depletion prior to liver transplantation may improve posttransplantation survival, particularly among patients with HH.     

HFE and non-HFE hemochromatosis

Hereditary hemochromatosis (HH) is a disorder of iron metabolism in which enhanced absorption of dietary iron causes increased iron accumulation in the liver, heart, and pancreas. Most individuals with HH are homozygous for a point mutation in the HFE gene, leading to a C282Y substitution in the HFE protein. The function of HFE protein is unknown, but the available evidence suggests that it acts in association with beta2-microglobulin and transferrin receptor 1 to regulate iron uptake from plasma transferrin by the duodenum, the proposed mechanism by which body iron levels are sensed. The identification of HFE has established the foundation for a better understanding of the molecular and cellular biology of iron homeostasis and its altered regulation in HH. Additionally, the ability to accurately diagnose iron overload disorders has been strengthened, family screening has been improved, and evaluation of patients with other forms of liver disease complicated by moderate-to-severe iron overload is now possible. However, the role of HFE testing in generalized population screening for HH is still controversial. Recently, other forms of HH have been described that are not related to HFE but are due to mutations in genes coding iron transport proteins.