Rare lysosomal disease registries: lessons learned over three decades of real-world evidence.

Lysosomal storage disorders (LSD) are rare diseases, caused by inherited deficiencies of lysosomal enzymes/transporters, that affect 1 in 7000 to 1 in 8000 newborns. Individuals with LSDs face long diagnostic journeys during which debilitating and life-threatening events can occur. Clinical trials and classical descriptions of LSDs typically focus on common manifestations, which are not representative of the vast phenotypic heterogeneity encountered in real-world experience. Additionally, recognizing that there was a limited understanding of the natural history, disease progression, and real-world clinical outcomes of rare LSDs, a collaborative partnership was pioneered 30 years ago to address these gaps. The Rare Disease Registries (RDR) (for Gaucher, Fabry, Mucopolysaccharidosis type I, and Pompe), represent the largest observational database for these LSDs. Over the past thirty years, data from the RDRs have helped to inform scientific understanding and the development of comprehensive monitoring and treatment guidelines by creating a framework for data collection and establishing a standard of care, with an overarching goal to improve the quality of life of affected patients. Here, we highlight the history, process, and impact of the RDRs, and discuss the lessons learned and future directions.

Recombinant macrophage targeted enzyme replacement therapy for Gaucher disease in India.

OBJECTIVE: Gaucher disease in India has been reported only in a few case reports from India. The aim of the study was to assess the response to enzyme replacement therapy in Indian patients with Gaucher disease. DESIGN: Retrospective analysis of patients receiving CHO-derived recombinant macrophage-targetted glucocorebrosidase. SETTING: Five centers from India with experience in treating lysosomal storage disorders. PATIENTS: The diagnosis of Gaucher disease was confirmed by low glucocerebrosidase levels, though it was first made on splenectomy in 8 and on bone marrow examination in 9 patients. Twenty five of 52 patients diagnosed with Gaucher disease (17 Type I, 8 mild Type III) received treatment for >6 months. Indications for treatment included symptomatic anemia, thrombo-cytopenia, organomegaly, bone disease or mild neurological symptoms leading to impairment of quality of life. Patients with significant neurological involvement were excluded. The drug infusions were given intravenously every 15 days. MAIN OUTCOME MEASURES: Hemoglobin, platelet counts, liver and spleen volumes and growth parameters. RESULTS: 22 of the 25 children who survived were analyzed. After 6 months of treatment, the mean (range) increase in hemoglobin was 1.5 (-3.4 to 6.1) g/dL (P=0.01) and in platelet count was 32 x 10(9)/L (-98.5 x 109 to 145.5 x10(9))/L (P=0.02). The mean (range) increase in weight was 3 kg (-5.6 to 10.5) (P=0.04) and in height was 7.1 cm (0 to 26.5) (P=0.0003). Liver size decreased by a mean (range) of 38.5% (- 5.5 to 86.7) (P=0.0003) and the spleen size by 34.8% (0 to 91.7) (P=0.004). All patients had improvement in bone pains and in 2 patients, neurological symptoms improved with others remaining static. CONCLUSIONS: This is the first reported cohort of patients in India reporting our experience with imiglucerase enzyme replacement therapy for treatment of Gaucher Disease in India.

Long-term outcomes of liver transplantation in type 1 Gaucher disease.

Gaucher disease (GD) is the most prevalent lysosomal storage disorder. Enzyme replacement therapy (ERT) has demonstrable efficacy in reversing clinical and pathological manifestations of GD. We report four patients with GD and severe hepatic impairment who were successfully treated by orthotopic liver transplantation. Liver failure resulted from GD in two patients and due to a comorbidity in two others (HCV and autoimmune chronic active hepatitis). Following successful liver transplantation, patients received long-term ERT. Liver transplantation is a life-saving treatment for end-stage liver disease in patients with Gaucher disease. All four patients have had excellent outcomes from liver transplantation for up to 10 years postprocedure with no evidence of Gaucher-related pathology in the graft.

Management of non-neuronopathic Gaucher disease with special reference to pregnancy, splenectomy, bisphosphonate therapy, use of biomarkers and bone disease monitoring.

Enzyme replacement was introduced as treatment for non-neuronopathic Gaucher disease more than 15 years ago. To ensure the best use of this costly ultra-orphan agent, a systematic disease management approach has been proposed by an international panel; this includes the development, by consensus, of achievable treatment goals. Here we critically review these goals and monitoring guidelines and incorporate emerging experience of the disease in the therapeutic era, as well as contemporary clinical research. This review makes recommendations related specifically to the management of pregnancy; the appropriate use of splenectomy and bisphosphonate treatment; the relevance of biochemical markers to disease monitoring; and the use of semi-quantitative methods for assessing bone marrow infiltration. In addition, we identify key areas for development, including the requirement for a validated index of disease severity; the need to correlate widely used biomarkers with long-term disease outcomes, and the desirability of establishing agreed standards for monitoring of bone disease particularly in infants and children with Gaucher disease.

Enzyme replacement therapy and bony changes in Egyptian paediatric Gaucher disease patients.

BACKGROUND: In Gaucher disease, the infiltration of the bone marrow by glucocerebroside-laden macrophages (Gaucher cells) triggers a diverse pattern of skeletal disease that results in crippling complications. Reliable ascertainment of the severity and pattern of skeletal disease is essential to determine disease status and the response to enzyme replacement therapy (ERT). Although there is ample documentation of reversal of haematological and visceral disease by ERT, there is a paucity of data on skeletal response to ERT in children. AIM: To delineate the pattern of bone disease in children with Gaucher disease in Egypt and to evaluate its response to ERT. METHOD: Twenty-two children with Gaucher disease were treated with ERT. Phenotyping by clinical, laboratory and radiological criteria was performed at baseline and following 11.2 +/- 4 months of ERT. Genotyping for glucocerebrosidase (GBA) mutations was performed by gene sequencing, and genotype-phenotype correlations were performed.Results. Two-thirds of the patients were from consanguineous pedigrees and 14/22 patients were homozygous or compound heterozygous for L444P and D409H mutations. Bone involvement was detected by plain radiology in 11 children (50%) and in 16 (73%) by magnetic resonance imaging (MRI). There was no correlation of severity of bone involvement and GBA genotype. ERT ameliorated bone disease: 10 of the 11 children with abnormal radiographic findings at baseline showed improvement in skeletal lesions; while 9/16 showed improvement of marrow disease by MRI. Radiographic sensitivity and specificity were 62% and 82% compared to MRI for detection of bone involvement in this patient population. At baseline, bone pain was present in 5 patients and ERT resulted in complete symptomatic remission in all of them. ERT was associated with significant improvement in growth parameters and amelioration of haematological and visceral involvement. CONCLUSION: Symptomatic and radiological skeletal disease is common in children with Gaucher disease in Egypt. MRI is the most accurate technique for detecting early skeletal involvement. There was no correlation between severity of skeletal involvement and GBA genotype. ERT was effective in ameliorating radiological manifestations of skeletal disease and achieving complete remission of bone pain.

Molecular diagnosis of Wilson disease.

Wilson disease (WD) is caused by mutations in the ATP7B gene. The diagnosis is based on clinical and biochemical criteria but these are increasingly recognized to have low sensitivity. Genetic diagnosis is considered impractical due to the large coding region of the ATP7B gene and extreme diversity of mutations. We assessed the feasibility and utility of genetic diagnosis in WD. The coding region of the ATP7B gene was scanned by single-stranded conformation polymorphism (SSCP) analysis in 6 cases in whom the diagnosis of WD was uncertain. In addition, we attempted molecular diagnosis in 26 WD patients of similar ethnicity but variable disease manifestations. In 6 individuals in whom the biochemical/clinical diagnosis was uncertain, DNA analyses were useful for assigning their status with respect to WD. Molecular diagnosis identified presymptomatic individuals in families affected by WD and assigned heterozygote carrier or wild-type status to individuals previously diagnosed as affected. In 26 WD patients, 92% of disease alleles were identified. The most common mutations were H1069Q, L936X, and 2532delA representing 48, 10, and 8% of disease alleles, respectively. Three novel mutations were identified: Q898R, 3061(-1)g --> a, and 3972insC. Genetic diagnosis is feasible for WD. Greater application of molecular diagnosis should enable an appreciation of the full spectrum of WD phenotype that is not possible with currently available diagnostic criteria.

Oxidative-phosphorylation defects in liver of patients with Wilson's disease.

BACKGROUND: Wilson's disease (WD) is caused by mutations in a P-type ATPase and is associated with copper deposition in liver and brain. The WD protein is present in the trans-Golgi network and may also be imported into mitochondria. The WD protein functions as a P-type copper transporting ATPase in the Golgi but any action in mitochondria is at present unknown. METHODS: We studied mitochondrial function and aconitase activity in WD liver tissue and compared the results with those in a series of healthy controls and patients without WD. FINDINGS: There was evidence of severe mitochondrial dysfunction in the livers of patients with WD. Enzyme activities were decreased as follows: complex I by 62%, complex II+III by 52%, complex IV by 33%, and aconitase by 71%. These defects did not seem to be secondary to penicillamine use, cholestasis, or poor hepatocellular synthetic function. INTERPRETATION: The results show that there is a defect of energy metabolism in WD. The pattern of enzyme defects suggests that free-radical formation and oxidative damage, probably mediated via mitochondrial copper accumulation, are important in WD pathogenesis. These results provide a rationale for a study of the use of antioxidants in WD.

Management of liver failure in a haemophilic patient co-infected with human immunodeficiency and hepatitis C viruses.

We present a case of liver failure in a haemophilic patient coinfected with transfusion acquired human immunodeficiency (HIV) and hepatitis C (HCV) viruses. The case illustrates the interaction of multiple viruses with accelerated progression to end stage liver disease and ultimately death. We report the impact on the patient management of two liver biopsies, which diagnosed an initial drug induced hepatitis and subsequently an atypical HCV related hepatitis.

Ulcerative colitis has an aggressive course after orthotopic liver transplantation for primary sclerosing cholangitis.

BACKGROUND: The course of inflammatory bowel disease after liver transplantation has been reported as variable with usually no change or improvement, but there may be an increased risk of early colorectal neoplasms. In many centres steroids are often withdrawn early after transplantation and this may affect inflammatory bowel disease activity. AIMS: To evaluate the course of inflammatory bowel disease in primary sclerosing cholangitis transplant patients who were treated without long term steroids. METHODS: Between 1989 and 1996, there were 30 patients transplanted for primary sclerosing cholangitis who survived more than 12 months. Ulcerative colitis was diagnosed in 18 (60%) patients before transplantation; two had previous colectomy. All patients underwent colonoscopy before and after transplantation and were followed for 38 (12-92) months. All received cyclosporin or tacrolimus with or without azathioprine as maintenance immunosuppression. RESULTS: Ulcerative colitis course after transplantation compared with that up to five years before transplantation was the same in eight (50%) and worse in eight (50%) patients. It remained quiescent in eight and worsened in four of the 12 patients with pretransplant quiescent course, whereas it worsened in all four patients with pretransplant active course (p=0.08). New onset ulcerative colitis developed in three (25%) of the 12 patients without inflammatory bowel disease before transplantation. No colorectal cancer has been diagnosed to date. CONCLUSIONS: Preexisting ulcerative colitis often has an aggressive course, while de novo ulcerative colitis may develop in patients transplanted for primary sclerosing cholangitis and treated without long term steroids.

Outcome of orthotopic liver transplantation in patients with haemophilia.

BACKGROUND: Many patients with haemophilia have developed cirrhosis or hepatocellular carcinoma due to transfusion acquired chronic viral hepatitis. AIMS: To assess the long term outcome of all haemophilic patients reported to have undergone orthotopic liver transplantation. METHODS: Transplant centres of patients identified by medical database search were contacted and survival data assessed by Kaplan-Meier analysis. RESULTS: Twenty six haemophilic men (median age 46 years, range 5-63 years) underwent orthotopic liver transplantation in 16 centres between 1982 and 1996. Indications for transplantation were hepatitis C cirrhosis (69%), hepatitis B with or without C cirrhosis (15%), viral hepatitis related hepatocellular carcinoma (12%), and biliary atresia (4%). Six patients (23%) were infected with human immunodeficiency virus (HIV). Postoperatively, the median time to normal clotting factor levels was 24 hours (range 0-48 hours) and exogenous clotting factors were stopped at a median of 24 hours (range 0-480 hours). Four patients (15%) had bleeding complications. The one and three year survival of HIV positive recipients (67% and 23%) was significantly poorer (p = 0.0003) than that of HIV negative recipients (90% and 83%). Coagulopathy was cured in all patients surviving more than 12 days post-transplant. Six of the 20 patients (30%) with hepatitis C cirrhosis pretransplant had evidence of disease recurrence at a mean of nine months post-transplant. CONCLUSIONS: Hepatitis C cirrhosis is the most common indication for orthotopic liver transplantation in patients with haemophilia. Transplantation results in long term cure of haemophilia but may be complicated by the effects of HIV infection or recurrent viral hepatitis.

A practical approach to diagnosis and management of Gaucher's disease.

The diagnosis of Gaucher's disease is established by demonstration of reduced acid beta-glucosidase activity in peripheral blood leukocytes. Genotyping at the glucocerebrosidase gene locus can give additional prognostic information and facilitate carrier detection. However, extreme phenotypic diversity precludes reliable prediction of prognosis in individual patients. Histological diagnosis of Gaucher's disease is unnecessary and can be misleading. A range of clinical, radiological and laboratory parameters are useful for staging disease activity which is central to achieving optimal timing to initiate enzyme therapy. Treatment should be individualized to obtain maximum therapeutic response. The recent introduction of chitotriosidase measurements has provided a valuable indicator of total cellular burden of storage cells. Serial measurements of chitotriosidase activity are useful for monitoring disease progression as well as response to therapy. A number of adjuvant therapies are available for use in conjunction with enzyme treatment. Special considerations apply to management of affected children.

Therapeutic delivery of proteins to macrophages: implications for treatment of Gaucher's disease.

BACKGROUND: The primary defect in Gaucher's disease, a lysosomal disorder affecting macrophages, is in the activity of glucocerebrosidase. Treatment with exogenous enzyme (modified to increase its affinity for macrophage glycoprotein receptors) aims to restore this activity. However, the fate of the exogenous enzyme in vivo is unknown. We used radiolabelled enzyme to assess macrophage receptor activity for mannosylated ligands in vivo. METHODS: We examined the uptake and tissue distribution of radiolabelled enzyme molecules by gamma scintigraphy after bolus injection of iodine-123-labelled recombinant or placental enzyme (imiglucerase and alglucerase, respectively) in eight patients with type 1 Gaucher's disease, and in one healthy individual. The metabolism of the tracer enzyme was followed by scintigraphy and by analysis of blood, urine, and faeces. RESULTS: The tracer enzyme was rapidly cleared from blood (half-life 4.7 min [SD 1.0]). Concomitantly, there was avid uptake by the liver (about 30% of the injected dose), the spleen (about 15%), and the bone marrow. 40-55% of the tracer was cleared rapidly from the viscera (half-life 1-2 h) and 45-60% was cleared slowly (half-life 34-42 h). The half-life in the bone marrow was 14.1 h. Infusion of alglucerase at dose of 5 U/kg bodyweight normalised acid beta-glucosidase activity of splenic Gaucher's cells in vivo. When the enzyme was administered at a seven-fold higher dose (35 U/kg over 1 h), the receptor-mediated uptake in vivo was saturated, as shown by the increase in blood-clearance half-life of tracer enzyme from 4.5 min to 12 min. INTERPRETATION: Avid and saturable uptake of modified glucocerebrosidase was found, which indicates high-affinity targeting to the macrophage system in vivo. The rate of enzyme turnover suggests a rational basis for use of this therapy in treatment of Gaucher's disease.

The association between free fatty acid concentrations and triglyceride-rich lipoproteins in the post-prandial state is altered by a common deletion polymorphism of the apo B signal peptide.

To investigate whether there were associations between the free fatty acid (FFA) response during a fat tolerance test and changes in concentrations of triglyceride-rich lipoproteins 57 healthy Caucasian men between 57 and 70 years of age underwent a fat tolerance test lasting 8 h. FFA concentrations initially decreased from 0.75 +/- 0.03 to 0.64 +/- 0.03 mmol/l at 2 h and thereafter increased to 1.2 +/- 0.04 mmol/l at 8 h. Maximum FFA concentration was the only significant determinant of 8 h triglyceride-rich lipoprotein (TGRLP) concentrations (pooled chylomicron and VLDL fractions d < 1.006) (TGRLP-TG r = 0.33, P = 0.012; TGRLP apo B r = 0.37, P = 0.004; TGRLP cholesterol r = 0.38, P = 0.004). The strength of the association between FFA and TGRLP was affected by the apo B signal peptide genotype. Only in individuals who were homozygous for the 27 amino acid (SP27 or I) allele of the apo B signal peptide were there significant associations between maximum FFA concentration quartile and 8 h TGRLP concentration (P value for linear trend = 0.025). In this genotype group there were lower HDL cholesterol concentrations (1.16 mmol/l compared to 1.38 mmol/l in subjects either heterozygous or homozygous for the SP24 [D] allele; P = 0.005) and there was a trend toward increased 8 h TGRLP concentrations. We propose that the association between post-prandial FFA concentrations and post-prandial TGRLP concentrations in individuals who are homozygous for the SP27 allele may be linked to the increased prevalence of ischemic heart disease (IHD) in this genotypic group.

Osteopontin is not a marker for proliferating human vascular smooth muscle cells.

Osteopontin (OP) is a secreted glycoprotein that contains the Arg-Gly-Asp (RGD) cell-binding sequence that binds calcium and is chemotactic and adhesive for rat vascular smooth muscle cells (VSMCs). OP gene expression is upregulated in cultured rat VSMCs in vitro and after balloon carotid injury in vivo, suggesting that OP may be a marker for proliferating VSMCs in vivo and in vitro. Our in situ hybridization studies of human atherosclerotic coronary vessels, however, have shown OP mRNA expression in plaque macrophages but not VSMCs. The current study investigated OP mRNA expression in cultured human VSMCs and macrophages and in an organ culture model of neointima formation in human saphenous vein. OP mRNA expression was not detected by Northern blot analysis of total RNA from subconfluent or confluent cultures of human VSMCs of any passage maintained in normal growth medium or after stimulation with TGF beta 1 (20 ng/mL), angiotensin II (1 mumol/L), or basic fibroblast growth factor (10 mg/mL) but was just detectable after stimulation with activation vitamin D3 (1 mumol/L). In contrast, cultured human macrophages expressed high levels of OP mRNA that were not dependent on lipid loading. OP mRNA was detected in isolated foci in all layers of saphenous veins maintained in organ culture for 14 days, including <2% of neointimal cells, a distribution that paralleled that of tissue macrophages. These results suggest that OP gene expression is not a marker for proliferation of human VSMCs in vitro and highlight a fundamental difference in the biology of human and rodent VSMCs.