Dysarthria and dysphagia in patients with mitochondrial diseases.

BACKGROUND: Information about dysarthria and dysphagia in mitochondrial diseases (MD) is scarce. However, this knowledge is needed to identify speech and swallowing problems early, to monitor the disease course, and to develop and offer optimal treatment and support. This study therefore aims to examine the prevalence and severity of dysarthria and dysphagia in patients with MD and its relation to clinical phenotype and disease severity. Secondary aim is to determine clinically relevant outcome measures for natural history studies and clinical trials. METHODS: This retrospective cross-sectional medical record study includes adults (age ≥ 18 years) diagnosed with genetically confirmed MD who participated in a multidisciplinary admission within the Radboud center for mitochondrial medicine between January 2015 and April 2023. Dysarthria and dysphagia were examined by administering the Radboud dysarthria assessment, swallowing speed, dysphagia limit, test of mastication and swallowing solids (TOMASS), and 6-min mastication test (6MMT). The disease severity was assessed using the Newcastle mitochondrial disease scale for adults (NMDAS). RESULTS: The study included 224 patients with MD with a median age of 42 years of whom 37.5% were male. The pooled prevalence of dysarthria was 33.8% and of dysphagia 35%. Patients with MD showed a negative deviation from the norm on swallowing speed, TOMASS (total time) and the 6MMT. Furthermore, a significant moderate relation was found between the presence of dysarthria and the clinical phenotypes. There was a statistically significant difference in total time on the TOMASS between the clinical phenotypes. Finally, disease severity showed a significant moderate relation with the severity of dysarthria and a significant weak relation with the severity of dysphagia. CONCLUSION: Dysarthria and dysphagia occur in about one-third of patients with MD. It is important for treating physicians to pay attention to this subject because of the influence of both disorders on social participation and wellbeing. Referral to a speech and language therapist should therefore be considered, especially in patients with a more severe clinical phenotype. The swallowing speed, TOMASS and 6MMT are the most clinically relevant tests to administer.

Blended cognitive behaviour therapy for children and adolescents with mitochondrial disease targeting fatigue (PowerMe): study protocol for a multiple baseline single case experiment.

BACKGROUND: Mitochondrial disease is a rare, hereditary disease with a heterogeneous clinical presentation. However, fatigue is a common and burdensome complaint in children and adolescents with mitochondrial disease. No psychological intervention targeting fatigue exists for paediatric patients with a mitochondrial disease. We designed the PowerMe intervention, a blended cognitive behaviour therapy targeting fatigue in children and adolescents with mitochondrial disease. The aim of the intervention is to reduce perceived fatigue by targeting fatigue-related cognitions and behaviours. METHODS: A multiple baseline single case experiment will be conducted in five children (8-12 years old) and 5 adolescents (12-18 years old) with mitochondrial disease and severe fatigue. Patients will be included in the study for 33 weeks, answering weekly questions about the fatigue. Patients will be randomly assigned a baseline period of 5 to 9 weeks before starting the PowerMe intervention. The intervention consists of face-to-face and online sessions with a therapist and a website with information and assignments. The treatment will be tailored to the individual. Each patient will work on their personalized treatment plan focusing on personally relevant goals. The primary outcome is perceived fatigue. Secondary outcomes are quality of life, school presence and physical functioning. DISCUSSION: The results of the PowerMe study will provide information on the efficacy of a blended cognitive behaviour therapy on reducing perceived fatigue and its impact on daily life in children and adolescents with mitochondrial disease. Strengths and limitations of the study design are discussed. TRIAL REGISTRATION: Dutch Trial Register NTR 7675. Registered on 17 December 2018. Identifier https://www.trialregister.nl/trial/7433.

Swallowing dysfunction in patients with nephropathic cystinosis.

INTRODUCTION: Nephropathic cystinosis is a rare autosomal recessive lysosomal storage disorder caused by mutations in the CTNS gene. Patients with nephropathic cystinosis suffer not only from renal disease but have also other systemic complications like myopathy and swallowing dysfunction. Dysphagia for solid food is mentioned in patients with cystinosis, but in clinical practice swallowing investigations are only performed when the patient has complaints. The aim of this study was to explore the swallowing function in patients with cystinosis by use of the Test of Mastication and Swallowing Solids (TOMASS), and to compare their performance with patients with myotonic dystrophy type 1 - a neuromuscular disease in which dysphagia for solid food is a known problem. METHODS: Twenty adult patients with cystinosis (11 men and 9 women, range 19-51 years) and 10 patients with myotonic dystrophy type 1 (5 men and 5 women, range 20-60 years) were included. All cystinosis patients were treated with cysteamine. Data of the two groups were compared with normative data using independent-samples t-tests. In case the variables were not normally distributed, the non-parametric Mann-Whitney U test was used. RESULTS: There was a significant difference in the number of bites, masticatory cycles, swallows and total time between the normal values and cystinosis patients. The results of the cystinosis patients were comparable to those of the patients with myotonic dystrophy. DISCUSSION AND CONCLUSION: Adult patients with cystinosis have significant dysphagia for solid food. Clinicians treating these patients should be aware of this fact. The TOMASS can be performed easily in clinical practice to investigate whether patients with cystinosis have swallowing dysfunction. The swallowing dysfunction can now be diagnosed by use of a non-invasive, very simple, non-harmful test. It can be discussed whether this should be added to the regular care scheme of cystinosis patients in order to regularly follow-up swallowing function.

TFR2-related haemochromatosis in the Netherlands: a cause of arthralgia in young adulthood.

BACKGROUND: Type 3 hereditary haemochromatosis (HH) is a rare iron overload disorder caused by variants in the transferrin 2 receptor (TFR2) gene. We aim to present characteristics of patients diagnosed with TFR2-HH in the Netherlands, in order to increase knowledge and awareness of this disease. METHODS: We collected clinical, biochemical and genetic data from four patients from three families diagnosed with HH type 3 in the Netherlands between 2009 and 2016. RESULTS: Three women and one man diagnosed with HH type 3 presented with arthralgia and elevated ferritin levels and transferrin saturation (TSAT) at ages 25-41 years. The hepcidin/ferritin ratio as measured in three patients was low. Liver iron content in two patients as assessed by MRI or liver biopsy was highly increased (250 and 362.7 µmol iron/g dry weight, respectively, reference < 35 µmol/g). DNA analysis revealed four different TFR2 pathogenic variants: one nonsense, one splicing and two missense variants, of which three are novel. Phlebotomy decreased the serum iron parameters but did not relieve the arthralgia. CONCLUSION: In patients with a combination of elevated TSAT and ferritin in the absence of anaemia, and after exclusion of HFE-related HH, rare forms of HH should be considered. In these cases, presentation with arthralgia in young adulthood, low hepcidin/ferritin ratio and/or liver iron content > 100 µmol/g form an indication for analysis of the TFR2 gene. Although type 3 HH is extremely rare, awareness of the disease among physicians is important in order to achieve an early diagnosis and prevent complications, such as liver damage.

PGM1 deficiency: Substrate use during exercise and effect of treatment with galactose.

Mutations in PGM1 (phosphoglucomutase 1) cause Glycogen Storage Disease type XIV, which is also a congenital disorder of protein N-glycosylation. It presents throughout life as myopathy with additional systemic symptoms. We report the effect of oral galactose treatment during five months in a patient with biochemically and genetically confirmed PGM1 deficiency. The 12-minute-walking distance increased by 225 m (65%) and transferrin glycosylation was restored to near-normal levels. The exercise assessments showed a severe exercise intolerance due to a block in skeletal muscle glycogenolytic capacity and that galactose treatment tended to normalize skeletal muscle substrate use from fat to carbohydrates during exercise.

Is 2D speckle tracking echocardiography useful for detecting and monitoring myocardial dysfunction in adult m.3243A>G carriers? - a retrospective pilot study.

OBJECTIVES: Cardiomyopathy is a common complication of mitochondrial disorders, associated with increased mortality. Two dimensional speckle tracking echocardiography (2DSTE) can be used to quantify myocardial deformation. Here, we aimed to determine the usefulness of 2DSTE in detecting and monitoring subtle changes in myocardial dysfunction in carriers of the 3243A>G mutation in mitochondrial DNA. METHODS: In this retrospective pilot study, 30 symptomatic and asymptomatic carriers of the mitochondrial 3243A>G mutation of whom two subsequent echocardiograms were available were included. We measured longitudinal, circumferential and radial strain using 2DSTE. Results were compared to published reference values. RESULTS: Speckle tracking was feasible in 90 % of the patients for longitudinal strain. Circumferential and radial strain showed low face validity (low number of images with sufficient quality; suboptimal tracking) and were therefore rejected for further analysis. Global longitudinal strain showed good face validity, and was abnormal in 56-70 % (depending on reference values used) of the carriers (n = 27). Reproducibility was good (mean difference of 0.83 for inter- and 0.40 for intra-rater reproducibility; ICC 0.78 and 0.89, respectively). The difference between the first and the second measurement exceeded the measurement variance in 39 % of the cases (n = 23; feasibility of follow-up 77 %). DISCUSSION: Even in data collected as part of clinical care, two-dimensional strain echocardiography seems a feasible method to detect and monitor subtle changes in longitudinal myocardial deformation in adult carriers of the mitochondrial 3243A>G mutation. Based on our data and the reported accuracy of global longitudinal strain in other studies, we suggest the use of global longitudinal strain in a prospective follow-up or intervention study.

The 6-min mastication test: a unique test to assess endurance of continuous chewing, normal values, reliability, reproducibility and usability in patients with mitochondrial disease.

In patients with mitochondrial disease, fatigue and muscle problems are the most common complaints. They also experience these complaints during mastication. To measure endurance of continuous mastication in patients with mitochondrial diseases, the 6-min mastication test (6MMT) was developed. This study included the collection of normal data for the 6MMT in a healthy population (children and adults). During 6 min of continuous mastication on a chew tube chewing cycles per minute, total amount of chewing cycles and the difference between minute 1 (M1 ) and minute 6 (M2 ) were collected in 271 healthy participants (5-80 years old). These results were compared with those of nine paediatric and 25 adult patients with a mitochondrial disease. Visual analogue scale (VAS) scores were collected directly after the test and after 5 min. A qualitative rating was made on masticatory movements. The reproducibility of the 6MMT in the healthy population with an interval of approximately 2 weeks was good. The inter-rater reliability for the observations was excellent. The patient group demonstrated lower total amount of chewing cycles or had greater differences between M1 and M6 . The 6MMT is a reliable and objective test to assess endurance of continuous chewing. It demonstrates the ability of healthy children and adults to chew during 6 min with a highly stable frequency of mastication movements. The test may give an explanation for the masticatory problems in patient groups, who are complaining of pain and fatigue during mastication.

Pre-eclampsia: an important risk factor for asymptomatic heart failure.

OBJECTIVES: Pre-eclampsia (PE) is associated with both postpartum structural asymptomatic heart disease (i.e. heart failure Stage B (HF-B)) and conventional cardiovascular (CV) risk factors. We aimed to evaluate the extent to which PE, adjusted for conventional CV risk factors, is associated independently with asymptomatic cardiac abnormalities postpartum. METHODS: In this cross-sectional cohort study, 107 formerly pre-eclamptic women and 41 women with uneventful previous pregnancy (controls) were invited for CV risk assessment 4-10 years postpartum. This included cardiac ultrasound, blood pressure (BP) measurement and evaluation of metabolic syndrome determinants. Asymptomatic structural and functional cardiac abnormalities were classified as HF-B, according to the American Heart Association guidelines. Prehypertension was defined as systolic BP of 120-139 mmHg and/or diastolic BP of 80-89 mmHg. Univariate and multivariate regression analyses were performed to calculate associations of PE and conventional risk factors with HF-B. RESULTS: The prevalence of asymptomatic HF-B was approximately 3.5-fold higher in the PE group compared with controls (25% vs 7%, P < 0.01); 67% of this group had concentric remodeling and 22% had mildly impaired ejection fraction. After adjustment for postpartum interval, hypertension and high-density lipoprotein, PE was significantly associated with HF-B (adjusted odds ratio, 4.4 (95% CI, 1.0-19.1)). Moreover, in the formerly pre-eclamptic group, prehypertension was associated significantly with HF-B (odds ratio, 4.3 (95% CI, 1.4-12.7)), while metabolic syndrome determinants were not. CONCLUSION: PE is associated with a four-fold increased female-specific risk of asymptomatic cardiac abnormalities. Prehypertension apparently increases this risk significantly, while metabolic syndrome determinants do not. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

A novel mutation in mitochondrial DNA in a patient with diabetes, deafness and proteinuria.

Maternally inherited deafness and diabetes (MIDD) is characterised by a defect in insulin secretion and bilateral hearing impairment. The m.3243A>G mutation is the most reported in mitochondrial DNA (mtDNA) causing MIDD, although other, rare, mtDNA point mutations have also been mentioned. We report on a 28-year-old Caucasian woman with a history of diabetes, kidney disease, deafness, diarrhoea, myopathy and fatigue. The diagnosis of mitochondrial disease was made in this patient, which resulted from a novel 09155A>G mutation in the mtDNA. As far as we know, this mutation has never been described before as causing MIDD.

Dysphagia, malnutrition and gastrointestinal problems in patients with mitochondrial disease caused by the m3243A>G mutation.

BACKGROUND: Previous research has shown that dysphagia and gastrointestinal problems occur frequently in carriers of the m.3243A>G mutation; however, the exact frequency and severity have not been determined. We hypothesise that adult carriers have an increased risk for malnutrition. METHODS: In this observational study we evaluated the presence of gastrointestinal problems and dysphagia in 92 carriers of the m.3243A>G mutation. The severity of the general disease involvement was classified using the Newcastle Mitochondrial Disease Adult Scale (NMDAS). Gastrointestinal involvement, dysphagia and the risk for malnutrition were scored using the Gastrointestinal Symptoms Questionnaire and the Malnutrition Universal Screening Tool. Gastrointestinal symptoms and anthropometrics were compared with healthy controls. RESULTS: Our results show that the height, weight and body mass index (BMI) of these carriers were lower than the national average (p < 0.05). Seventy-nine carriers (86%) suffered from at least one gastrointestinal symptom, mainly flatulence or hard stools. Both frequency and severity of symptoms were significantly increased compared with reference data of healthy Dutch adults. Of the carriers, 45% reported (mostly mild) dysphagia. Solid foods cause more problems than liquids. A negative correlation between BMI and heteroplasmy levels in urinary epithelial cells (UEC) was present (Spearman correlation coefficient = - 0.319, p = 0.003). CONCLUSION: Dysphagia and gastrointestinal problems, especially constipation, are common symptoms in the total m.3243A>G carriers cohort and are not related to heteroplasmy levels in UEC or disease severity. The severity of gastrointestinal problems as well as overall disease severity is associated with an increased risk for malnutrition.

Metabolic syndrome and the risk for recurrent pre-eclampsia: a retrospective cohort study.

OBJECTIVE: To compare the prevalence of recurrent pre-eclampsia between women who have and do not have metabolic syndrome when non-pregnant. DESIGN: Retrospective cohort study. SETTING: Three tertiary referral hospitals in the Netherlands. POPULATION: Formerly pre-eclamptic women. METHODS: The presence or absence of metabolic syndrome was assessed in 480 women at least 6 months after their first pre-eclamptic pregnancy using World Health Organization criteria. We compared the prevalence of recurrent pre-eclampsia in the subsequent pregnancy, calculating odds ratios (OR), adjusted for confounders. MAIN OUTCOME MEASURE: Recurrence of pre-eclampsia in the subsequent pregnancy. RESULTS: Subsequent pregnancy outcome data were available for 197 women. Forty women had metabolic syndrome after previous pregnancy (20%). The prevalence of recurrent pre-eclampsia was 18/40 (45%) in women with metabolic syndrome versus 27/157 (17%) in women without metabolic syndrome; OR 3.94 (95% confidence interval [CI] 1.86-8.33, adjusted OR 3.77 (95% CI 1.61-8.81). The risk of recurrent pre-eclampsia increased with each extra component of the metabolic syndrome from 11.8% for absent components up to 43.9% for three or more (P for trend < 0.001). CONCLUSIONS: Interpregnancy metabolic syndrome predisposes to recurrent pre-eclampsia.

The 48-hour tetrahydrobiopterin loading test in patients with phenylketonuria: evaluation of protocol and influence of baseline phenylalanine concentration.

BACKGROUND: The 24- and 48-hour tetrahydrobiopterin (BH4) loading test (BLT) performed at a minimum baseline phenylalanine concentration of 400 µmol/l is commonly used to test phenylketonuria patients for BH4 responsiveness. This study aimed to analyze differences between the 24- and 48-hour BLT and the necessity of the 400 µmol/l minimum baseline phenylalanine concentration. METHODS: Data on 186 phenylketonuria patients were collected. Patients were supplemented with phenylalanine if phenylalanine was <400 µmol/l. BH4 20mg/kg was administered at T = 0 and T = 24. Blood samples were taken at T=0, 8, 16, 24 and 48 h. Responsiveness was defined as ≥ 30% reduction in phenylalanine concentration at ≥ 1 time point. RESULTS: Eighty-six (46.2%) patients were responsive. Among responders 84% showed a ≥ 30% response at T = 48. Fifty-three percent had their maximal decrease at T = 48. Fourteen patients had ≥ 30% phenylalanine decrease not before T = 48. A ≥ 30% decrease was also seen in patients with phenylalanine concentrations <400 µmol/l. CONCLUSION: In the 48-hour BLT, T = 48 seems more informative than T = 24. Sampling at T = 32, and T = 40 may have additional value. BH4 responsiveness can also be predicted with baseline blood phenylalanine <400 µmol/l, when the BLT is positive. Therefore, if these results are confirmed by data on long-term BH4 responsiveness, we advise to first perform a BLT without phenylalanine loading and re-test at higher phenylalanine concentrations when no response is seen. Most likely, the 48-hour BLT is a good indicator for BH4 responsiveness, but comparison with long term responsiveness is necessary.

Risk factors for ischemic stroke and transient ischemic attack in patients under age 50.

To analyze risk factors for ischemic stroke and transient ischemic attack (TIA) in young adults under the age of 50. To make recommendations for additional research and practical consequences. From 97 patients with ischemic stroke or TIA under the age of 50, classical cardiovascular risk factors, coagulation disorders, history of migraine, use of oral contraceptives, cardiac abnormalities on ECG and echocardiography, and the results of duplex ultrasound were retrospectively analyzed. Literature was reviewed and compared to the results. 56.4% of the patients had hypertension, 12.1% increased total cholesterol, 20% hypertriglyceridemia, 31.5% an increased LDL-level, 32.6% a decreased HDL-level and 7.2% a disturbed glucose tolerance. Thrombophilia investigation was abnormal in 21 patients and auto-immune serology was abnormal in 15 patients. Ten of these patients were already known with a systemic disease associated with an increased risk for ischemic stroke (i.e. systemic lupus erythematosus). The ECG was abnormal in 16.7% of the cases, the echocardiography in 12.1% and duplex ultrasound of the carotid arteries was in 31.8% of the cases abnormal. Conventional cardiovascular risk factors are not only important in patients over the age of 50 with ischemic stroke or TIA, but also in this younger population under the age of 50. Thrombophilia investigation and/ or autoimmune serology should be restricted to patients without conventional cardiovascular risk factors and a history or other clinical symptoms associated with hypercoagulability and/ or autoimmune diseases.

Hereditary haemochromatosis.

Haemochromatosis should currently refer to hereditary iron overload disorders presenting with a definite and common phenotype characterised by normal erythropoiesis, increased transferrin saturation and ferritin and primarily parenchymal iron deposition related to innate low (but normally regulated) production of the hepatic peptide hormone hepcidin. Since the discovery of the haemochromatosis gene (HFE) in 1996, several novel gene defects have been detected, explaining the mechanism and diversity of iron overload diseases. Overall, at least four main types of hereditary haemochromatosis (HH) have been identified. This review describes the systematic diagnostic and therapeutic strategy and pitfalls for patients suspected for HH and their relatives.

Adult issues in phenylketonuria.

Phenylketonuria (PKU) is a classical example of an inherited metabolic disease, in which mental retardation can be prevented successfully by using a diet. However, in adult PKU new problems occur, such as vitamin deficiencies, osteoporosis and the maternal PKU syndrome. The aim of this review article is to provide guidelines for the clinician to understand and manage PKU in adults.

Inflammation in deep vein thrombosis and the development of post-thrombotic syndrome: a prospective study.

BACKGROUND: The aim of this study was to investigate whether inflammatory markers (interleukin-6 [IL-6] and C-reactive protein [CRP]) in the acute phase of deep vein thrombosis (DVT) are associated with elevated venous outflow resistance (VOR), thrombosis score (TS), reflux and the development of clinical post-thrombotic syndrome (PTS). METHODS: In 110 patients with a first DVT, plasma concentrations of IL-6 and CRP were determined on the day of admission. VOR, TS and reflux were measured 7 days, 1 and 3 months after diagnosis. After 1 year patients were evaluated for PTS using the Clinical, Etiologic, Anatomic and Pathophysiologic (CEAP) classification and Villalta scale. RESULTS: Median levels of IL-6 and CRP were 7 pg mL(-1) and 21 mg L(-1), respectively. After 3 months, VOR was elevated in 33 patients (30%), TS in 33 (30%) and reflux in 57 (52%). Incidence of PTS was 36.7% using CEAP>or=3 and 35.4% using Villalta-scale>or=5. Elevated levels of IL-6 and CRP were related to higher outcomes of VOR after 3 months [relative risks (RR) 2.4 (95% CI 1.5-3.9) and 1.4 (1.1-3.3), respectively] and for IL-6 to TS [1.5 (1.1-2.1)]. For reflux no relation was found. After 90 days, elevated outcomes of VOR, TS and reflux were related to PTS after 1 year. The association of IL-6 and CRP with PTS was weak using the CEAP classification with a RR of 1.2 (0.7-2.2) and 1.8 (0.9-3.3) and absent according to the Villalta scale 0.6 (0.2-1.4) and 1.2 (0.6-2.5), respectively. CONCLUSION: The results of this study suggest that inflammation might play a role in incomplete thrombus clearance, venous outflow obstruction and the development of PTS after 1 year.

Multilayer compression bandaging in the acute phase of deep-vein thrombosis has no effect on the development of the post-thrombotic syndrome.

OBJECTIVE: The purpose of this randomized study was to evaluate the influence of immediate multilayer compression bandages before application of elastic stockings in the acute phase of deep-vein thrombosis (DVT) on development of the post-thrombotic syndrome (PTS). METHODS: Sixty-nine patients with acute symptomatic DVT were randomized to immediate bandaging (n = 34) or no bandaging (n = 35). After reduction of edema sized-to-fit elastic stockings were applied in all patients after 7-14 days. Follow-up visits and non-invasive examinations were planned after 7, 30 and 90 days and 1 year. Venous outflow resistance (VOR) was measured by strain gauge plethysmography. Thrombosis score (TS) and reflux were measured by duplex scanning. After one year patients were evaluated for clinical PTS using both the clinical scale of the CEAP classification and the Villalta score. RESULTS: Improvement of clinical symptoms and decrease of leg circumference was better on day 7 in the bandaging group, but after 1 and 3 months clinical symptoms had improved equally in both groups. In 7 patients in the no-bandaging group a bandage was applied after all because of persistent edema after 10 days. There were no differences in VOR, TS and reflux. Using the CEAP classification the incidence of PTS was 39% in patients with bandages and 42% in patients without bandages (RR 0.91, 95% CI 0.50-1.66). Using the Villalta score the incidence of PTS was resp. 29 and 33% (RR 0.87, 95% CI 0.41-1.8). There was no difference in severity of PTS. CONCLUSION: Immediate multilayer compression bandaging in the acute phase of DVT is effective in reducing edema and complaints in the first week, but has no effect on thrombus regression, valve incompetence and the development of clinical PTS after 1 year.

Indications of combined vitamin K antagonists and aspirin therapy.

Based on their mode of action, it is reasonable to expect that the combination therapy of aspirin and a vitamin K antagonist (VKA) may be more beneficial in preventing (athero) thrombotic complications in high-risk patients for cardiovascular events. However, there is no consensus about additional aspirin use in the most common indications for VKA or the use of VKAs to be added to the most common aspirin indications. The variation in clinical outcomes and bleeding complications suggests that extrapolating from one indication to another may not be appropriate. So far, decisions about the combined use of aspirin and VKA are individualized in the absence of adequate data. Only in patients with mechanical heart valves the benefits and safety of combining aspirin with VKA therapy seems obvious. In patients with peripheral artery disease no beneficial effect was noted for the combination therapy, perhaps with an exception of those with graft failure. For all other clinical situations, this is unclear and should be avoided.

[Hereditary haemochromatosis: novel genes, novel diseases and hepcidin]. / Hereditaire hemochromatose: nieuwe genen, nieuwe ziekten en hepcidine.

Since the discovery of the HFE gene of hereditary haemochromatosis in 1996 several new genetic defects have been identified, enabling explanation of the cause and variety of this disease. To date, at least 5 major types of hereditary haemochromatosis have been recognised. All these genes encode for proteins that are involved in metabolic pathways relevant to hepcidin synthesis in the liver. Hepcidin is a small protein that regulates the activity of the iron exporting protein ferroportin in the basolateral membrane of duodenal cells and the cell membrane of macrophages and thereby controls serum iron concentration. Plasma hepcidin concentration is elevated in body iron excess and by inflammatory stimuli, and is lowered in erythroid iron demand, hypoxia and most types of hereditary haemochromatosis. It is the clinician's task to diagnose hereditary haemochromatosis before irreversible tissue damage arises and at the same time to differentiate between ongoing iron accumulation and increasingly prevalent disorders with elevated serum ferritin such as the metabolic syndrome.