Dr.moosavi Abadan-Khordad-1397 Hemochromatosis Dr.moosavi Abadan-Khordad-1397

OBJECTIVES Review iron absorption and transport Describe types of hemochromatosis Hemochromatosis and the laboratory Suspicion Investigation Diagnosis

Iron Absorption and Transport

Background Iron is an important nutrient, but too much can be bad Absorb about 10% from our diet Individual with this disease absorbs about 30% No mechanism to eliminate iron Excess damages liver, heart, and pancreas

Villus enterocyte Ferritin Macrophage Ceruloplasmin Transferrin Bone Marrow Liver

Normal Iron metabolism Male Female Total body iron Daily iron absorption Daily iron loss OTHER Menstrual (monthly) pregnancy (total) 3 - 4 g 1 – 2 mg 1- 2 mg 2 - 3 g 1 – 2 mg 1- 2 mg OTHER 20 - 40 mg 600 - 900 mg

20 mg / d Menstruation 20 – 40 mg /m Ferritin Macrophage Villus enterocyte Fe2+ 1 – 2 mg /d 20 mg / d Liver Menstruation 20 – 40 mg /m Bone Marrow

20 mg / d Menstruation 20 – 40 mg /m Ferritin Macrophage Villus enterocyte Fe2+ 20 mg / d 7 – 8 mg /d 1 – 2 mg /d Liver Menstruation 20 – 40 mg /m Bone Marrow

Iron transport and absorption proteins Transferrin Ferritin Transferrin receptor Ceruloplasmin

Non-heme iron absorption process Reduction of ferric to ferrous iron Transport across brush border Sequestration in enterocyte Basal transport from cell Oxidation to ferric form Transport by transferrin Uptake by transferrin receptors Utilisation or storage

Types of Hemochromatosis

Different Forms Primary or hereditary Secondary Juvenile Neonatal

Classical or adult-onset Hemochromatosis

Classical Hemochromatosis First description 1865 inherited disorder 1935 autosomal recessive disorder of excess iron deposits in parenchymal tissues causing organ damage and dysfunction Affects liver, pancreas, heart, joints, pituitary, skin – “bronze diabetes” Considered rare disease of elderly men

Hemochromatosis by 1996 Syndrome preventable if iron overload diagnosed and treated early. Treatment simple: - phlebotomy Recognition – high transferrin saturation and ferritin Studies of blood donors suggested that 1:200 to 1:400 people have biochemical iron overload Much more common than originally thought 1 in 200 in NW European populations

Hereditary HFE is gene for protein that regulates iron absorption 2 mutations: C282Y and H63D

North West European origin C282Y mutation in HFE gene In late 1996 an HLA linked gene on chromosome 6 p 21.3 was found to be associated with hemochromatosis patients of North West European origin HFE B C E A HLA genes

Early Stage Symptoms Arthritis Fatigue Abdominal pain High blood sugar Hypothyroidism Weight loss

Advanced Stage Symptoms Liver disease Liver cancer Diabetes Cardiac arrhythmia Congestive heart failure Discolored skin

Clinical Manifestations Influenced by Age Sex Dietary iron Alcohol Blood loss in menstruation and pregnancy Unknown factors Alcohol abuse and Hepatitis C accelerate Classic description: cutaneous hyperpigmentation and diabetes in a patient with cirrhosis

Traditional triad means diagnosed too late! Classic Triad: Cirrhosis (hepatic damage) Diabetes (type II) (pancreatic damage) Bronzing of skin (hyperpigmentation) Traditional triad means diagnosed too late! Damage may be only partially reversible Goal is to detect the disease BEFORE organ damage occurs Slide 5: Symptoms: Traditional Concept There is a misconception that most hemochromatosis patients present with this classic triad when in fact fewer than 15% of patients do.3 Diagnosis at this point means it is too late to prevent organ damage. Goal is to identify and treat patients before they reach this stage. Organ damage may only be partially reversible at this point.

Hepatocellular carcinoma During follow-up, hepatocellular carcinoma developed in 28 of the 97 (28.8%) patients with cirrhosis but in none of those without The risk was increased significantly in patients > 55 yrs, those with HBS Ag and alcohol abuse Prognostic factors for hepatocellular carcinoma in genetic hemochromatosis. Hepatology 1994 Dec;20(6):1426-31

Diagnostic testing for HH Transferrin saturation: > 45% indicates significant Fe accumulation Serum ferritin - levels indicating significant iron accumulation: >150 mcg/L pre-menopausal women >200 mcg/L post-menopausal women >200 mcg/L for men Liver biopsy if ferritin >1000 to assess damage Consider genetic testing – DNA testing for common mutations (C282Y, H63D) Slide 15: Diagnostic Testing for HH Fasting transferrin saturation (TS): 2 > 45% indicates significant Fe accumulation (sensitivity and specificity 94%)3 TS = Serum iron x 100% Total Iron Binding Capacity (TIBC) The easiest way to get TS levels is to order serum iron and TIBC then do the TS calculation if the lab does not do the calculation for you Patient must be fasting as TS can be increased after a meal in which there is large iron content. Serum ferritin: at these levels indicates significant iron accumulation3 Liver biopsy if ferritin >1000 in HH to assess damage2 Genetic testing – DNA testing for common mutations (C282Y, H63D)2

Iron overload in liver Pearls’ Prussian blue stain of a liver biopsy from a patient with hereditary hemochromatosis. Left panel: low-power view shows intense iron stainingof hepatocytes. The blue-stained iron deposits typically start at the periphery of the liver lobule and extends centrally. Right panel: high-power view shows intense on staining (in blue) of hepatocytes. Courtesy of Stanley L. Schrier, M.D.

Hepatic Iron Index (HII) in hemochromatosis - the hepatic Iron index in four groups of patients: normal controls, alcoholic liver disease, pre-fibrotic hemochromatosis, and fibrosis and cirrhosis caused by hemochromatosis. Among the patients with hemochromatosis, the opens circles represent heterozygotes, andthe close circles represent homozygotes. The HII iscalculated by dividing the hepatic iron concentration by the patients age in years. All patients with homozygous hereditary hemochromatosis had an hepatic I index > 2, alevel not seen in the otherpatients. Hepatology 1986; 6:24

MRI Liver Slow (approx 20 mins) Relatively simple Good correlation with iron levels and cirrhosis

Genetic Testing for HH Should be offered to those patients with: Appropriate clinical presentation Elevated transferrin saturation and ferritin Liver biopsy suggestive of iron overload First degree relative of a known case * Must be offered to an affected family member or index case FIRST Slide 16: Genetic Testing for HH should be offered to those patients with: Must be offered to an affected family member FIRST A known mutation should be identified before offering DNA testing to other family members. If the affected family member is unavailable, then refer relatives to genetics clinic for counseling and evaluation. First-degree relatives or spouse (if there are adult children at risk since if spouse is negative, no need to test children) of a diagnosed case of HH. Some genetics centres offers testing to first-degree relatives of a carrier because HH is so common.

What is the value of genetic testing? To confirm diagnosis Sequential screening of family members Slide 17: What is the value of Genetic Testing? Think of the whole family as your patient. Genetic testing allows you to identify family members at risk of developing hemochromatosis. Predictive value: Once at-risk family members are identified, a screening or treatment plan can be developed to prevent organ damage and reduce morbidity and morality. Screening plan to monitor for iron overload: Serum Ferritin Fasting Transferrin Saturation Treatment plan to reduce further organ damage. Phlebotomy (500mL) weekly or biweekly until serum ferritin falls below 50ng/mL2 Diet: Avoid iron supplements, vitamin C and raw fish.

“So if I have the gene…I’ll get the disease” Not necessarily! This statement refers to an important concept in genetics Penetrance The proportion of individuals with a mutation causing a particular disorder who exhibit clinical symptoms of that disorder Slide 23: “So if I have the gene…I’ll get the disease” Penetrance is defined as the proportion of individuals with a mutation (or genotype) known to cause a specific disease who exhibit clinical symptoms of that disorder. So, for hemochromatosis, that would be the proportion of individuals with a C282Y/C282Y or C282Y/H63D or H63D/H63D genotype who exhibit clinical symptoms of hemochromatosis. Note that the penetrance depends on the specific genotype involved: C282Y/C282Y (majority of cases) > C282Y/H63D > H63D/H63D (very few people have symptoms).

Mutated HFE Genes = Hemochromatosis? No, because of Incomplete penetrance: Even though some individuals have the susceptible genotype they may never manifest symptoms of the disease due to: Environmental factors: blood donation Genetic factors: other modifying genes Low penetrance for C282Y homozygotes Slide 24: Mutated HFE Genes = Hemochromatosis? Incomplete penetrance: Incomplete penetrance refers to the phenomenon that not every person with a mutant genotype will exhibit clinical symptoms of the disorder. Some factors contributing to incomplete penetrance (in HH) are environment, diet, alcohol, lifestyle (donating blood) and age at menarche & menopause, heaviness of periods, number of pregnancies, use of iron supplements and other genetic factors (modifier genes). From the European Consensus Conference on Haemochromatosis in 2000, the proportion of C282Y homozygotes that will have iron overload assessed by serum ferritin is 19-58%.5 The exact penetrance of hemochromatosis is still under study but ranges from 1% to 55% to 100% in the literature.17 More recent data suggests the penetrance is lower than previous reports. One of the reasons for the range in penetrance is that the various studies have different definitions of hemochromatosis and different methods of ascertainment (study of blood donors’ verses a study of patients followed in a hemochromatosis clinic). This brings us to a philosophical question: What constitutes disease? Genotype: People with two HFE mutations (C282Y/C282Y or H63D/H63D homozygotes, C282Y/H63D compound heterozygotes)? – But they may never develop clinical symptoms of iron overload. Biochemistry: People with the abnormal biochemistry, elevated TS (‘biochemical penetrance’) but no symptoms of iron overload? One study in Wales found that 85% of men and 44% of women with the C282Y/C282Y genotype had elevated TS – again these people may not develop clinical symptoms. 1 Clinical presentation: People with symptoms of iron overload – cirrhosis, cardiomyopathy, type 2 diabetes etc? Thus the definition of disease can vary depending on what is being referred to; genotype or serum iron measures or symptoms of iron overload. One of the problems in determining the penetrance of HH is that the various studies have different definitions of the clinical signs leading to the wide range of the reported percentage of penetrance.

Guidelines

Indications to consider hemochromatosis Guidelines: Iron Overload 2001 Apply to classical Type 1 Hemochromatosis General guidelines – indications for genetic testing Based on fasting transferrin saturation as the primary biochemical screen

When to consider the diagnosis? Adult onset diabetes Arthritis Unexplained cirrhosis or persistently raised liver enzymes Congestive heart failure or cardiomyopathy Secondary hypogonadism Increased skin pigmentation Not in guideline Severe fatigue Arthralgias

Genetic Testing and Treatment First degree relatives of confirmed hemochromatosis patients can have the genetic test done directly If iron overloaded and not C282Y homozygous consider other causes Management (phlebotomy) is dependent on the ferritin level not the transferrin saturation Phlebotomy - till ferritin around 50 µg/L

No Yes No Yes Yes No Yes No Yes No Yes No Fasting morning TS >50% Stop Yes No Repeat TS and serum ferritin > normal Check in 12 mo Yes Yes Secondary Iron Overload? Rx & Recheck No HFE gene testing; C282Y homozygote? Yes 1. Normal AST 2. Ferritin <1000 ug/L 3. No hepatomegaly No Yes No Phlebotomy Liver Biopsy - positive for HHC Yes No Phlebotomy Follow

Medical Management The goal - detect patients before symptoms of iron overload. Phlebotomy weekly or biweekly Check ferritin every ~10 phlebotomies Stop frequent phlebotomy when ferritin 25-50mcg/L Maintenance phlebotomy every 3-4 months Dietary recommendations Consider hematology or GI consult for confirmed cases to guide treatment and monitoring Slide 25: Medical Management 3, 6, 2 The goal of treatment is to detect patients before they manifest symptoms of iron overload. Early treatment can prevent organ damage and improve survival Some symptoms may be reversible with phlebotomy Phlebotomy: Removal of 400-500mL of blood weekly or biweekly Check hematocrit prior to each phlebotomy; allow hematocrit to fall by no more than 20% of normal Check ferritin every ~10 phlebotomies Stop frequent phlebotomy when ferritin 20-50mcg/L or transferring saturation is <30% Continue phlebotomy at intervals (every 3-4 months) to keep serum ferritin between 20-50mcg/L Dietary recommendations: Patients should avoid: Vitamin C (increases the absorption of iron) and iron supplements Excessive consumption of alcohol Eating raw shellfish – A marine bacteria, Vibrio vulnificus causes septicemia and high mortality especially in people with chronic liver disease or other dysfunction that increases serum iron levels i.e. HH.18 Consider hematology or GI consult for confirmed cases to guide treatment and monitoring. Management of C282Y heterozygotes (carriers)6 In C282Y heterozygotes who have indirect markers of iron overload, especially if they have abnormal liver enzymes or clinical evidence of liver disease - a liver biopsy is recommended to diagnose HH. C282Y heterozygotes that have iron overload may carry a second undetected, RARE mutation in the HFE gene. Generally C282Y and H63D heterozygous carriers are not at risk for iron overload.

Chelation therapy for HHC with deferoxamine can also lead to clinical improvement, however, it is almost never necessary

Diet Realistically little role Avoid large quantities Vitamin C Increased Fe absorption Increases Fe release from storage sites Rare reports of inducing lethal cardiac failure