Correction of fatal genetic diseases using bone marrow transplantation. 1

Bone marrow transplantation (BMT) was mainly used for the treatment of immunological, hematological and oncological diseases. Genetic diseases can also be treated by transplantation of normal histocompatible allogeneic bone marrow. This type of marrow transplantation is used for the treatment of inborn errors whose clinical expression is restricted to lymphoid or hematopoietic cells. The therapeutic role of bone marrow transplantation in the treatment of generalized genetic diseases is under investigation. Genetic disorders that can be cured include congenital immune deficiencies, infantile malignant osteopetrosis, thalassemia, infantile agranulocytosis, chronic granulomatous disease, lysosomal storage diseases and others. The use of autologous bone marrow after the insertion of a normal gene (gene therapy) in vitro circumvents the need for a histocompatible donor.     

Inborn errors of metabolism: the clinical diagnosis in early infancy

Major advances occurring in recent years in the recognition and treatment of inborn errors of metabolism have made it more essential than ever that the physician be familiar with the clinical presentation of these disorders. Although infants with inborn errors of metabolism will continue to be best cared for in centers with expertise in the treatment of inherited metabolic disease, the initial recognition of these disorders remains the responsibility of the practicing physician. A clinical approach to the diagnosis of inborn errors of metabolism in the young infant is presented as well as suggestions for the use of readily available laboratory studies that can serve to identify these infants who will benefit from further evaluation and treatment.     

Liver cell transplantation

Liver cell transplantation is an emerging procedure, consisting of infusing mature adult hepatocytes in the portal system of the recipient. It aims to correct inborn errors of liver metabolism, bridge unstable patients to transplantation, or even allow bridge to recovery in fulminant liver failure. The technique addresses ideally patients with inborn errors of metabolism, unstable but not sick enough for orthotopic transplantation. Best results have so far been obtained in metabolic diseases, such as urea cycle disorders, glycogenosis type I, Crigler Najjar, Refsum disease and factor VII deficiency. Cryopreserved hepatocytes can be used, allowing delay between cell isolation and patient's transplantation. The percentage of engraftment obtained can reach up 10%, with de novo expression of deficient enzyme activity. Better results of engraftment have been obtained in animal studies by different chemical or physical techniques, but not yet applied in humans. Because supply of human cells can be limited, research also aims to obtain transplantable cells from other sources, such as embryonic or adult stem cells, or liver progenitor cells that could be expanded in vitro. Careful progression in this field, and collaboration between centers are mandatory to validate further the technique for wider clinical use.     

Treatment of adenosine deaminase deficiency with adenosine deaminase combined with polyethylene glycol]

Adenosine deaminase (ADA) deficiency is one the causes of severe combined immunodeficiency syndrome. Treatment was, until now, based on bone marrow transplantation. HLA identical bone marrow transplantation yields excellent results while those of HLA haploidentical bone marrow transplantation are not so good. A new therapeutic approach was developed recently, consisting of the intramuscular infusion of ADA enzyme covalently linked to polyethylene glycol (PEG-ADA). We report the results of this treatment in a 14 month-old child presenting with a partial form of ADA deficiency revealed by an opportunistic infection. This treatment corrected the immunodeficiency and the biochemical abnormalities as well. PEG-ADA infusions were well tolerated. The onset of an immunization against the ADA enzyme led to a drop in immunologic functions, which could be partially overcome by more frequent (biweekly) administration of the product. After a 18 month-follow-up the child is doing well, living normally at home. PEG-ADA represents a possible alternative for children presenting with ADA deficiency without any available HLA identical donor.     

Outcome of Displacement Bone Marrow Transplantation for Inborn Errors of Metabolism

The concept of displacement bone marrow transplantation arose from our work at Westminster 1970–1973, by which time we had extended the donors from matched siblings to other family and unrelated donors. DBMT is not a panacea, but can be applied to about 7% of understood inborn errors, where it is possible to devise in vitro tests to predict in vivo donor effects. Its use to install donor bone marrow as a component factory for the life of the recipient, and the importance of immunoprophylaxis are summarised. Worthwhile correction has been achieved for 48 previously fatal genetic diseases, partial correction for another five, but there has been failure for three diseases. Some 80% of our patients were not found in known families and could not have been prevented.     

Gene therapy for inborn errors of liver metabolism: progress towards clinical applications

The treatment for inborn errors of liver metabolism is based on dietary, drug, and cell therapies (orthotopic liver transplantation). However, significant morbidity and mortality still remain, and alternative strategies are needed. Gene replacement therapy has the potential of providing a definitive cure for patients with these diseases. Significant progress has been made in the pre-clinical arena and achievement of efficacy in different animal models has been reported using multiple gene transfer technologies. This article summarizes the gene transfer strategies being investigated, the pre-clinical data, and the available early clinical results for inborn errors of liver metabolism.     

Long-term effects of bone marrow transplantation for inborn errors of metabolism: A study of four patients with lysosomal storage diseases

Long-term effects of bone marrow transplantation (BMT) were evaluated in patients with I-cell disease, metachromatic leukodystrophy (MLD), Maroteaux-Lamy syndrome or Hunter syndrome (mild form). Donors were human leukocyte antigen (HLA)-matched siblings, and the follow-up periods were 24–71 months after BMT. The enzyme activities were increased in leukocytes, plasma or liver tissues compared with pre-BMT levels. A patient with I-cell disease acquired development of 4–8 month old infants and showed no further progression in cardiac dysfunctions. A patient with MLD showed a decelerated disease progression and an improved peripheral neuropathy, but progressive brain atrophy was not prevented. Patients with Maroteaux-Lamy syndrome or Hunter syndrome showed improvements in hepatomegaly, joint contractures, short stature and tight skin, and this greatly increased their quality of life. These results indicated that the long-term therapeutic effects achieved by BMT were subject to multiple factors including biochemical improvements, a reversibility of affected tissues, or advanced states of disease and central nervous system impairments in inborn errors of metabolism.     

Immune deficiencies secondary to enzymopathies

Immune deficiencies secondary to enzyme deficiencies that affect purine and pyrimidine metabolism account for approximately 50% of severe immune deficiencies inherited as a recessive autosomal trait. Adenosine deaminase (ADA) deficiency is the most common and also the earliest and most severe of these diseases. ADA deficiency is responsible for a severe combined immune deficiency with alymphocytosis and often characteristic bone and cartilage abnormalities. The treatment of choice is transplantation of compatible bone marrow; in cases where this has not been feasible, replacement therapy with the enzyme coupled to polyethylene glycol has yielded promising results. Purine nucleoside phosphorylase (PNP) deficiency is responsible for an isolated T cell defect. Low serum uric acid levels are highly suggestive of PNP deficiency. Bone marrow transplantation is indicated. In both diseases, the immune deficiency is due to the toxic effect of purine deoxynucleosides on lymphoid cells. Enzyme deficiencies that directly or indirectly affect pyrimidine metabolism (orotate phosphoribosyltransferase and methionine synthase deficiencies) are exceedingly rare and only inconsistently produce an immune defect (involving T cells).     

先天性遗传代谢病的早期诊断

目的提高儿科医生对新生儿期遗传代谢病的认识，做到早期诊断、早期治疗。方法自2003年9月至2004年9月，根据临床表现确定18名遗传代谢病高危患儿，用“滤纸片代”将采集的尿标本外寄进行气相色谱．质谱(GC／MS)分析，筛查遗传代谢病。结果18例高危儿中确诊为遗传代谢病5例，分别为戊二酸尿症Ⅱ型1例(46h，男)，鸟氨酸氨甲酰转移酶缺陷1例(66h，男)，枫糖尿病1例(8d，男)，甲基丙二酸血症1例(13d，男)，丙酸血症1例(21d，女)，并对其临床特点进行归纳总结。结论掌握新生儿遗传代谢病临床特点，对高危儿早期进行尿GC／MS分析，可以早期诊断遗传代谢病，有利于优生优育。     

Human genetics and transplantation]

Transplantations represent an important element of treatment in end-stage chronic disease both inborn (mostly genetic) and acquired (degenerative, neoplastic). They are supposed to establish durable coexistence of cells with different genetic origin (in most cases). This union is contradictory to immunological properties of the tissues involved and can only succeed in case of sufficient histocompatibility to be identified by the diagnostic tests of immunogenetics. This review discusses the current approach used in choosing the most appropriate donor for an individual patient, and in monitoring the maintenance of "chimerism" established by the transplantation focussing on bone marrow transplantation. Initially a general outline of indications for organ transplantation is given with emphasis laid on genetic disorders as the outlook of conservative treatments in inborn diseases is generally very poor.     

Anaesthesia for liver transplantation in two infants with an organic acidaemia

Liver transplantation is an accepted option of treatment in patients with inborn errors of metabolism limited to or mainly located into hepatocytes who have not responded well to medical treatment. Recurrent metabolic failure and neurological impairment might be an indication for early transplantation in patients with organic acidaemias. We discuss the anaesthetic management and metabolic implications of acidaemia in the first two cases of successfully treated propionic and methylmalonic acidaemia in Italy. A nine and 12 month follow up did not show any further metabolic failure after the procedure, indicating that early liver transplantation improves the quality of life of these patients.     

Critical care of the pediatric hematopoietic stem cell recipient in 2005

Abstract:  Among the most challenging patients cared for in critical care medicine are the recipients of hematopoietic stem cell transplantation (HSCT). HSCT is now widely used as a definitive therapy for the treatment of pediatric malignancies and inborn errors of metabolism. Critical care services are required for treatment of complications of HSCT. Formerly thought to have an essentially futile prognosis, outcomes from critical care of HSCT patients have demonstrated steady improvement in many areas during the past two decades. Improvements in the management of respiratory failure, sepsis, and multiple organ system failure have resulted from improvement in oncology and critical care practices. Herein, we review the methods available for outcomes prediction, recent advances in critical care of HSCT patients, and possible directions for future investigation.     

Use of hematopoietic growth factors for treatment of aplastic anemia

The recent discovery and manufacture of recombinant human hematopoietic growth factors offers a novel approach to treating patients with aplastic anemia. There are ongoing preclinical trials of a number of recombinant proteins that demonstrate remarkable hematopoietic activity in a variety of bone marrow failure states. Moreover, there are preliminary results of phase I/II trials of the administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with aplastic anemia. It appears that this factor, the first to reach the stage of actual clinical trials, effectively increases proliferation of myeloid cellular elements of the peripheral blood and bone marrow, particularly in patients with milder forms of aplastic anemia. The side effects of GM-CSF at low to moderate doses of the growth factor (less than 16 micrograms/kg/day) appear tolerable. These results suggest that GM-CSF holds promise as a therapeutic option for patients with aplastic anemia. Long-term clinical trials will be needed to assess accurately the role that GM-CSF and other promising hematopoietic growth factors can play in the treatment of this disease, relative to other therapies such as antithymocyte globulin and bone marrow transplantation.     

Autologous bone marrow transplantation in the treatment of children and adolescents with advanced malignant tumors

Nineteen patients with advanced malignant tumors, less than 20 years old were treated with intensive chemotherapy (vincristine 2 mg/m² i.v. and adriamycin 60 mg/m² i.v. on day ?7; cyclophosphamide 45 mg/kg i.v. on days ?6 to ?3), total body irradiation (TBI, 600 rads on day ?1) and autologous bone marrow transplantation (ABMT, day 0). Prior to this procedure induction of complete or partial remission by conventional therapy was attempted. Ten patients had intra-abdominal non-Hodgkin's lymphoma (NHL); three, yolk sac tumor; three, Ewing's sarcoma; and three, neuroblastoma. The supportive care included reverse isolation, immunoglobulin 400 mg/kg i.v. q 2 weeks, cotrimoxazole per os, and cell support as needed. No correlation between the bone marrow dose and the time of hematological reconstitution could be established. Five of seven patients with intraabdominal NHL stage III (transplanted in first remission) are surviving disease-free for 5 +, 5 +, 20 +, 23 +, and 35 + months after ABMT. None of three patients with intra-abdominal NHL stage IV is surviving (two of them were transplanted in second remission). One of three patients with yolk sac tumor is surviving disease-free for 27+ months. There are no survivors among the patients with Ewing's sarcoma and neuroblastoma. Only one of 19 patients was lost due to therapeutic complications, while 12 died due to tumor. Regarding treatment results for advanced intra-abdominal NHL, the procedure described here is comparable to the best conventional regimens. In vitro methods for tumor cell eradication in the collected bone marrow might further improve the results of ABMT.     

Clinical approach to inborn errors of metabolism presenting in the newborn period

Inborn errors of metabolism are individually rare, but collectively are responsible for significant levels of paediatric morbidity and mortality. More than 400 biochemically diverse inborn errors of metabolism have been identified. Recent advances in the diagnosis and treatment of these disorders have substantially improved the prognosis for many of them. Paediatricians and neonatologists play a vital role in identifying which patients need to be investigated. The diagnosis of an inborn error of metabolism often needs to be established quickly in order to prevent death or permanent neurological sequelae, and this should be carried out in collaboration with a specialized unit. The present review provides a practical approach to the recognition and investigation of neonates in whom an inborn error may be present. We also provide guidelines for the stabilization and initial management of infants at high risk of a metabolic disorder.     

Angeborene Stoffwechselstörungen

The diagnosis of inborn errors requires in addition to a thorough assessment of the medical history and clinical examination specialised diagnostic testing, including biochemical and molecular tests. Genetic counselling should be offered to all families due to the increased recurrence risk for future pregnancies. Basic diagnostic testing of blood (full blood count, electrolytes, glucose, acid-base status, creatine kinase, triglycerides, lactate and ammonium) as well as of urine (urine dipstick for glucose, protein and ketone bodies) will give a first impression as to whether an inborn error of metabolism may be likely. Importantly, additional samples should be drawn during the acute presentation prior to initiation of treatment and stored until further analysis. Some variants and atypical forms of inborn errors of metabolism may not be detected by newborn screening. If such a disorder is suspected clinically specific metabolic testing should be initiated even following a normal newborn screening result. It should also be kept in mind that newborn screening programmes only screen for a limited number of inborn errors of metabolism and that a normal screening result does not preclude the diagnosis of an inborn error of metabolism.     

Phenotypes in heteroglycanoses and sphingolipidoses (author's transl)

Sphingolipidoses and heteroglycanoses are inborn errors of the carbohydrate metabolism. Biochemically and clinically hetero-glycanoses are sub-divided into mucopolysaccharidoses, oligosaccharidoses and mucolipidoses. These disorders of complex carbohydrate metabolism are due to the inborn defect of one or more lysosomal enzymes which in turn cause an intracellular accumulation of not-degraded complex carbohydrates corresponding to a wide pattern of clinical expression and symptomatology ranging from psychomotor retardation without any dysmorphic signs to severe features of a storage disease with dwarfism, peculiar facial appearance, organomegaly and skeletal changes. Investigations of recent years revealed that there is tremendous phenotypic variation even within diseases caused by a deficiency of the same enzyme. On the other hand, clinically indistinguishable phenotypes may be caused by the defect of different enzymes.     

Vitamin B6 resistant primary hyperoxaluria type I. Report of 5 cases

Primary hyperoxaluria type I (PH I) is characterized by an excessive endogenous production and excretion of oxalic and glycolic acid. Prognosis of this "inborn error of metabolism" is not favorable due to calcium-oxalate depositions in kidney and other organs. Vitamin B6 administration and/or renal transplantation can greatly improve the prognosis, as reported in literature. In this article our experience with 5 patients with vitamin B6 resistant hyperoxaluria is reported. Symptomatology and progression of the primary disease are described. The results of treatment interfering with oxalate production and calcium-oxalate crystallization are given. Three patients underwent renal replacement therapy. In these, oxalosis developed during hemodialysis and progressed following transplantation; a disabling bone disease was the most severe complication. Outcome of transplantation was disappointing. In two out of three patients, there was recurrence of the primary disease in the graft. In only one of them long-term graft function was satisfying. However, even this good function could not prevent disabling symptoms of oxalosis. Therefore, evaluation of the results of transplantation should not only include data related to graft function and survival, but also the complications due to calcium-oxalate depositions in various organs. To prevent oxalosis, kidney transplantation should be performed before end stage renal disease is achieved in patients with vitamin B6 resistant PH I.     

Cardiac manifestations of inborn errors of metabolism

AIM: The aim of the study was to investigate the frequency and type of cardiac manifestations in a defined group of patients with inborn errors of metabolism. This paper also explores the key role of cardiac manifestations in the diagnosis of inborn errors of metabolism in daily practice. METHODS: Out of the 287 patients with the potential for inborn errors of metabolism who had been referred to the University Hospital of Heraklion (202 children and adolescents and 85 adults), 41 were found to have a variety of cardiac manifestations, including cardiomyopathy, cardiomegaly, atrioventricular conduction disorders and coronary artery disease. RESULTS: In 15 out of the 41 patients a diagnosis of inborn errors of metabolism was established, while the total number of patients with inborn errors of metabolism was 60 out of the 287. In 6 out of the 15 patients the major symptoms were from the cardiovascular system and 7 of them were adults with symptoms initiating in childhood. CONCLUSION: The cardiac findings consist of a neglected area in the diagnosis of the inborn errors of metabolism. Neurologists, pediatricians and internists should cooperate with cardiologists in managing people with unexplained cardiac symptoms and signs and be aware that several inborn errors of metabolism are associated with cardiac abnormalities and mild neurologic findings.