Deep brain stimulation in Lesch-Nyhan syndrome: a systematic review

Given the good results of deep brain stimulation (DBS) in the treatment of movement disorders, DBS was initially tried to treat Lesch-Nyhan syndrome (LNS) with the aim to alleviate LNS-related dystonia. Some cases have reported clinical results of DBS in LNS thus far. This systematic review was conducted to comprehensively summarize cases of LNS treated with DBS and evaluate the efficacy and safety of DBS in LNS. Eight publications covering 12 LNS patients were included in this review. DBS improved dystonia of the LNS to varying degrees. All the included cases achieved partial or complete control of self-injurious behavior (SIB). Overall, DBS is a promising treatment for both motor and behavior disorders of LNS patients, but the results reported thus far have varied widely, especially for motor outcomes. The ultimate clinical benefits in LNS patients were still unpredictable. DBS-related complications were rather common, which raised questions about the safety of the procedure in LNS. More research is needed to further clarify the safety and effectiveness of this treatment.

[Treatment of self-injurious behaviors in Lesch-Nyhan syndrome with S-adenosylmethionine]

An 11-year-old boy with Lesch-Nyhan syndrome (LNS) had persistently injured himself by biting his lips and buccal mucosa since infancy. Risperidone was only partially effective in suppressing this behavior. Oral administration of S-adenosylmethionine (SAMe), involving increasing the dose from 400 mg to 1 g, resulted in the amelioration of self-injurious behavior and anxiety as well as marked improvement in his self-esteem, performance at school, and friendships. No adverse effects were noted. SAMe may have a favorable effect on symptoms of LNS by activating monoaminergic pathways and/or increasing the adenosine pool in the salvage pathway of guanosine monophosphate synthesis. Defects in these pathways have been essentially implicated in the neurological pathophysiology of LNS.

Genotypic and phenotypic spectrum in attenuated variants of Lesch-Nyhan disease

Lesch-Nyhan disease and its attenuated variants are caused by deficiency of the purine salvage enzyme, hypoxanthine-guanine phosphoribosyltransferase (HGprt). All patients exhibit excessive production of uric acid, which increases the risk for nephrolithiasis, renal failure, gouty arthritis and tophi. The mildest phenotype includes only problems related to overproduction of uric acid. The most severe clinical phenotype includes prominent neurological abnormalities and the universal feature is self-injurious behavior. In between the mildest and most severe syndromes is a broad spectrum of phenotypes with varying degrees of neurological, neurocognitive and behavioral abnormalities. The effect of HPRT1 gene mutations on residual HGprt enzyme activity is the most relevant factor contributing to disease phenotype. Attenuated clinical phenotypes are associated with residual enzyme function, whereas the most severe phenotype is usually associated with null activity. In cases of gouty arthritis with urate overproduction, a careful evaluation for motor impairments or neurocognitive abnormalities may help to identify attenuated variants of Lesch-Nyhan disease for better management.

The 50th anniversary of gene therapy: beginnings and present realities

Applying my experience in microbial genetics, especially in the genetic transformation/transduction of Bacilus subtilis bacteria, I decided around 1956 to develop a similar system for eukaryotic, especially human cell cultures. I believed it would permit the development of clinical applications for replacing defective genes to treat or cure some of the genetic diseases.

Successful unrelated umbilical cord blood transplantation in Lesch-Nyhan syndrome

Lesch-Nyhan syndrome (LNS) is a chronic, progressive neurodevelopmental disorder causing motor and behavioral dysfunction due to decreased synthesis of the enzyme hypoxantine-guanine phosphoribosyltransferase (HPRT). Affected boys have mental retardation, delayed development, extrapyramidal motor disturbances and self-injuring behavior. As hematopoietic stem cell transplantation (HSCT) has been shown to be effective in several neurodevelopmental inborn errors, we hypothesized that it could be favorable in LNS as well. Following a myeloablative conditioning regimen (busulphan 3.2 mg/kg/day for 4 days, cyclophosphamide 60 mg/kg/day for 2 days with ATG Thymoglobin 2.5 mg/kg/day for 4 days) an unrelated umbilical cord blood unit was transfused at the age of 2 years. The graft was a 6/6 HLA-matched at HLA-A, B loci by antigen level, and at DRB1 by allelic level typing. Infused total nucleated cell dose was 3.6 × 10e7 per kilogram body weight. Serum HPRT levels reached normal values by the end of the sixth month post transplant. Slow neurodevelopmental improvement seen during the three-year follow-up and the missing self-injuring behavior can be considered as a proof for the presence of enzyme-competent cells behind the blood-brain barrier.

Opposite effects of internal globus pallidus stimulation on pallidal neurones activity

Besides clinical efficacy, the mechanisms of action of deep brain stimulation (DBS) are still debated. To shed light on this complex issue, we have taken the opportunity to record the response of globus pallidus internus (GPi) neurones to 100 Hz stimulations in a case of Lesch-Nyhan syndrome (LNS) where four pallidal electrodes were implanted. Three types of response were observed, 2/19 neurones were unaffected by DBS. About 7/19 neurones were inhibited during DBS stimulation and 10/19 neurones were excited during DBS stimulation. Both effects ceased when DBS was turned off. Inhibited neurones were situated lower that exited ones on the trajectory (1.25 and 4.65 mm above the center of GPi respectively). These observations suggest that locally DBS induces a reversible inhibition of neurone firing rate while at the same time distantly exciting the main afferents to and/or efferents from the GPi. Both actions would result in a strong GPi inhibition that does not preclude increased outflow from the GPi.

Dramatic reduction in self-injury in Lesch-Nyhan disease following S-adenosylmethionine administration

A man with Lesch-Nyhan disease (LND; OMIM 300322) experienced significantly reduced self-injury and improved comfort while receiving S-adenosylmethionine.

Medical diagnosis, management and treatment of Lesch Nyhan disease

The aim of this presentation is to inform about Lesch Nyhan Disease from the point of view of the affected boys and their families living with the condition from day to day and also to show the importance of research in treating and managing the disease (In Caring for Children with Lesch Nyhan Disease--A Guide for Parents and Professionals; McCarthy, G.T., Ed.; PUMPA and Chailey Heritage Clinical Services: East Sussex, UK, 2002).

Hyperuricemia and bone marrow transplantation

Blood uric acid levels and purine metabolism are affected in many ways after bone marrow transplantation (BMT). Although BMT is usually performed when patients have a low residual disease burden, a proportion of them are still at risk of tumor lysis syndrome, even with limited disease or after nonmyeloablative conditioning regimens; moreover, an alteration in uric acid turnover can also be observed in patients with persistently normal uric acid blood levels. Apart from this obvious complication, multiple physiopathological events occurring after transplantation may derange uric acid homeostasis. Although there is only indirect evidence (derived from obstetric eclampsia and experimental gout arthritis), a transplant-related increase in cytokine production (particularly TNF, IL-1 and IL-6) may activate xanthine oxidase which, in turn, may be responsible for a further cytokine bout: deranged cytokine homeostasis is involved in the pathogenesis of some of the main acute post-BMT complications, such as hepatic veno-occlusive disease (VOD) and acute graft-versus-host disease (aGVHD). Hyperuricemia is also a well-known side effect of cyclosporine A, the reference drug for the prevention of post-BMT GVHD, which may affect uric acid turnover by reducing glomerular filtration and/or affecting tubular handling; the available evidence favors the former explanation. Hyperuricemia is found in long-term transplanted patients as part of a metabolic pattern reminiscent of the so-called 'X' or 'metabolic'syndrome related to insulin resistance: there is still no precise interpretation of this post-transplant complication nor any definite data concerning its real incidence and outcome. Hyperuricemia is frequently regarded as a marginal finding in the context of X syndrome, but it is pathogenetically linked to the other component of the syndrome and has proved to be autonomously responsible for tissue and vessel damage. Finally, BMT is a possible therapeutic strategy for some inherited forms of hyperuricemia, particularly Lesch- Nyhan disease, although there is still some perplexity concerning the possibility of preventing the development of neurological impairment.

Disappearance of self-mutilating behavior in a patient with lesch-nyhan syndrome after bilateral chronic stimulation of the globus pallidus internus. Case report

Lesch-Nyhan syndrome (LNS) is an X-linked hereditary disorder caused by a deficiency of hypoxanthine-guanine phosphoribosyltransferase. Patients with this syndrome are characterized by hyperuricemia, self-mutilation, developmental retardation, and movement disorders such as spasticity and dystonia. The authors performed bilateral chronic stimulation of the globus pallidus internus for control of dystonic movements in a 19-year-old man with LNS. His self-mutilating behavior unexpectedly disappeared after chronic stimulation. This is the first case of LNS that has been successfully treated with deep brain stimulation. The findings indicate that neurobehavioral features of this syndrome are either mediated in the basal ganglia pathways or secondary to the dystonia.

End-of-life care for a man with developmental disabilities

BACKGROUND

Science can artificially maintain many essential life functions. Does such care prolong life or dying?

METHODS

A case is described of a patient with developmental disability with unknown health care choices who was hospitalized for drug-resistant urosepsis. He developed aspiration pneumonia, deep vein thrombosis, and respiratory arrest. He required gastrostomy, tracheostomy, artificial ventilation, parenteral nutrition, hemodialysis, multiple anti-infective agents, and blood transfusions. On day 58, a bioethics committee recommended against cardiopulmonary resuscitation. On day 66, the patient's conservator concurred but required continuation of artificial ventilation. To the dismay of some caretakers, the patient continued to receive intrusive care until his death on day 104. The hospital charge was $709,206.

RESULTS AND CONCLUSION

Hospital care of patients with mental incapacity can be clinically and ethically challenging. End-of-life decisions can be facilitated when the patient's legal representative and physician actively advocate the patient's best interests and communicate frequently and openly. Suggestions are made for such exigencies.

[Treatment of Lesch-Nyhan syndrome]

AIM

We have reviewed the treatments employed to alleviate the different manifestations of the Lesch Nyhan syndrome, the adverse reactions related to these treatments, and the prospectives of future therapeutic approaches now under active research.

DEVELOPMENT

Lesch Nyhan syndrome is an X linked inherited disorder of purine metabolism caused by the deficiency of the enzyme hypoxanthine guanine phosphoribosyltransferase (HPRT). Clinical features include overproduction of uric acid and a neurologic syndrome related to the severity of the enzyme defect.

CONCLUSIONS

Treatment with xanthine oxidase inhibitors is effective for the control of the elevated renal excretion of uric acid, but there is no specific treatment for the neurologic symptoms. Due to the low frequency of the syndrome and to the incomplete understanding of the pathophysiologic mechanisms underlying the neurologic manifestations, the treatments employed are merely symptomatic.

Partial hypoxanthine-Guanine phosphoribosyltransferase deficiency as the unsuspected cause of renal disease spanning three generations: a cautionary tale

Hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency is an X-linked defect of purine metabolism. Clinical manifestations are usually related to the degree of enzyme deficiency: complete HPRT deficiency (Lesch-Nyhan syndrome) presenting with severe neurologic or renal symptoms, or partial HPRT deficiency (Kelley-Seegmiller syndrome) manifesting as a gout-urolithiasis syndrome. A 3-generation kindred is described in which the recognition of partial HPRT deficiency in 2 adolescent male siblings presenting with uric acid lithiasis led to the diagnosis in 2 maternal uncles already in renal failure of unknown cause. This report highlights the importance of clinical awareness leading to early diagnosis, appropriate diagnostic methodology, and therapy of a treatable inherited disorder of purine metabolism for the prevention of renal failure.

[The Lesch-Nyhan syndrome]

Deficiency of hypoxanthine phosphoribosyltransferase (HPRT) has a broad spectrum of clinical manifestations, from the complete enzyme defect, the Lesch-Nyhan syndrome with severe neurological deficiency to the partial defect associated only with uric acid overproduction and its consequences. We present a 5-year old boy with Lesch-Nyhan syndrome. He came to our hospital because of abdominal pain, vomiting and gross haematuria. At the age of 8 months he was categorized as a "cerebral palsy" patient due to involuntary movements and high degree of spastically and tonic spasms. He remained incapable of sitting or standing alone. The patient's brother and two uncles were also categorized as "cerebral palsy" cases and died at the age of 8-14 years. Clinical examination revealed hyperuricaemia and hyperuricosuria, radiolucent renal and urinary bladder stones. HPRT enzyme activity was totally absent, while adenine phosphoribosyl transferase activity was increased compared to control. The patient was treated with allopurinol, urinary alkalization, low-purine diet and adequate hydration while he was in hospital. However, his parents refused further treatment and follow-up. The most important issue is whether the healthy sisters of the patients are heterozygotes for HPRT deficiency. This DNA analysis is now in progress.

A review of behavioral treatments used for Lesch-Nyhan syndrome

Lesch-Nyhan syndrome is a genetic disorder resulting in hyperuricemia, choreoathetosis, mental retardation, and self-mutilation. The most salient feature of this disorder is the self-injurious behavior (SIB). Although the utility of behavioral interventions with SIB has been well documented, behavioral interventions with Lesch-Nyhan syndrome have been limited in number and long-term success. This article reviews the behavioral treatments that have been used in treating individuals with Lesch-Nyhan syndrome and discusses the strengths and weaknesses of these methods. Suggestions for future directions in the use of behavioral interventions for controlling SIB in Lesch-Nyhan syndrome are provided.

Adenoviruses encoding HPRT correct biochemical abnormalities of HPRT-deficient cells and allow their survival in negative selection medium

The Lesch-Nyhan syndrome is an X-linked disorder caused by a virtually complete absence of the key enzyme of purine recycling, hypoxanthine-guanine phosphoribosyltransferase (HPRT). It is characterized by uric acid overproduction and severe neurological dysfunction. No treatment is yet available for the latter symptoms. A possible long-term solution is gene therapy, and recombinant adenoviruses have been proposed as vectors for gene transfer into postmitotic neuronal cells. We have constructed an adenoviral vector expressing the human HPRT cDNA under the transcriptional control of a short human cytomegalovirus major immediate early promoter (RAd-HPRT). Here we show that infection of human 1306, HPRT-negative cells with RAd-HPRT, expressed high enough levels of HPRT enzyme activity, as to reverse their abnormal biochemical phenotype, thus enhancing hypoxanthine incorporation and restoring purine recycling, increasing GTP levels, decreasing adenine incorporation, and allowing cell survival in HAT medium in which only cells expressing high levels of HPRT can survive. Infection of murine STO cells, increased hypoxanthine incorporation and restored purine recycling, thus allowing cell survival in HAT medium, and reduced de novo purine synthesis. Although both cells were able to survive in HAT medium post infection with RAd-HPRT, some of the biochemical consequences differed. In summary, even though adenoviral vectors do not integrate into the genome of target HPRT-deficient human or murine cells, RAd-HPRT mediated enzyme replacement corrects abnormal purine metabolism, increases intracellular GTP levels, and allows cells to survive in a negative selection medium.

Gene therapy and the brain

In this article we describe the application of the emerging concepts of gene therapy to 4 different neurologic disorders. The first of these is Lesch-Nyhan disease, a genetically-determined neurodevelopmental disorder caused by a defect in the gene which encodes the purine salvage enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). Two additional disorders, Parkinsonism and Alzheimer's disease, are both neurodegenerative diseases of unknown etiology which affect the elderly. The final disorder involves malignant brain tumors. In each of these disorders, basic research with in vitro systems and animal models has suggested that the tools of gene transfer may provide a novel and potentially effective treatment strategy.

Lesch-Nyhan syndrome: successful prevention of lower lip ulceration caused by self-mutilation by use of mouth guard

Lesch-Nyhan syndrome (LNS) is a disorder caused by congenital absence of a purine metabolic enzyme, hypoxanthine guanine phosphoribosyl-transferase (HGPRT). This syndrome is characterized clinically by hyperuricemia and neurologic features including choreoathetoid spasticity, self-mutilation, and mental retardation. We report on a patient in whom self-mutilation of the lower lip was suppressed with the help of a mouth guard made from soft resin.

Cognitive abilities of patients with Lesch-Nyhan disease

Parents of 42 patients with Lesch-Nyhan disease completed a questionnaire systematizing caregiver observations of the subject's behavior during a wide variety of daily events. Responses were grouped in nine categories reflecting different aspects of cognitive skills. Only 1 boy appears to have any significant generalized cognitive impairment. The patients' memory for both recent and past events is excellent, their emotional life has a normal range of reactions and is appropriate; they have good concentration, are capable of abstract reasoning, have good self-awareness, and are highly social. However, they are behind in academic ability, with only 15% at grade level for math and reading. Implications for designing educational activities, parenting or caregiver strategies, and research methodology are discussed.

Approaches to gene therapy in disorders of purine metabolism

Model studies with gene transfer technology using retroviral vectors expressing the cloned human genes for adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), and hypoxanthine guanine phosphoribosyltransferase (HPRT) indicate that these disorders may eventually be treated by the introduction of the normal gene into defective cells. The autologous transplantation of bone marrow infected in vitro with retroviral vectors is the most developed approach at this time. The potential usefulness of this and other approaches for each of these three disorders of purine metabolism are discussed.

Glial cells metabolically cooperate: a potential requirement for gene replacement therapy

Immunofluorescently labeled glial cells are shown by radioautography to metabolically cooperate with hypoxanthine phosphoribosyltransferase-deficient fibroblasts. The observations of cooperation without cell contact and of incorporation gradients around the glial cells suggest that cooperation occurs through extracellular transport of radiolabeled purine compounds. The transfer of radiolabeled adenine, adenosine, or methylthioadeninosine is supported by the quantitative loss of cooperation when the recipient cell is also deficient in enzymes required for adenine or adenosine salvage. The demonstration of glial cell cooperation provides impetus for current research toward gene replacement therapy for the neurologic symptoms of the Lesch-Nyhan syndrome.

Human gene therapy: scientific and ethical considerations

The term "gene therapy" encompasses at least four types of application of genetic engineering for the insertion of genes into humans. The scientific requirements and the ethical issues associated with each type are discussed. Somatic cell gene therapy is technically the simplest and ethically the least controversial. The first clinical trials will probably be undertaken within the next year. Germ line gene therapy will require major advances in our present knowledge and it raises ethical issues that are now being debated. In order to provide guidelines for determining when germ line gene therapy would be ethical, the author presents three criteria which should be satisfied prior to the time that a clinical protocol is attempted in humans. Enhancement genetic engineering presents significant, and troubling, ethical concerns. Except where this type of therapy can be justified on the grounds of preventive medicine, enhancement engineering should not be performed. The fourth type, eugenic genetic engineering, is impossible at present and will probably remain so for the foreseeable future, despite the widespread media attention it has received. There are four potential levels of the application of genetic engineering for the insertion of gene into a human being. Somatic cell therapy: this would result in correcting a genetic defect in the somatic (i.e.,body) cells of a patient. Germ line gene therapy: this would require the insertion of the gene into the reproductive tissue of the patient in such a way that the disorder in his or her offspring would also be corrected. Enhancement genetic engineering: this would involve the insertion of a gene to try to "enhance" a known characteristic; for example, the placing of an additional growth hormone gene into a normal child. Eugenic genetic engineering: this is defined as the attempt to alter or "improve" complex human traits each of which is coded by a large number of genes; for example, personality, intelligence, character, formation of body organs, and so on.

Treatment package to reduce SIB in a Lesch-Nyhan patient

Self-destructive behaviour in LNS children results in a tremendous burden to parents, teachers, staff members, and other responsible for their care. As constant vigilance is not always feasible, developing alternate methods of managing SIB becomes imperative. This report presents our efforts to improve the care of an LNS child and to ease the burden on staff members and parents by obtaining special devices (e.g. the custom-made mouthguard and the gloves) to prevent him from injuring himself. Others (e.g. Letts & Hobson, 1975) have likewise reported success in fabricating custom-designed chairs and devices in an effort to manage SIB in LNS children. Their devices were, however, more elaborate and much more expensive than the ones used in this report. The cost of obtaining a mouthguard similar to the one used with K. is estimated at between $20-$30 (US), while the gloves cost only $14.00. The major advantages of using such devices are that they safely allow employment of the extinction procedure along with allowing the child to participate more fully in activities of daily living. It is recognized that K. was in some ways an atypical Lesch-Nyhan child in that he possessed low normal receptive intelligence and scored fairly high (relative to most LNS children) on a test of verbal intelligence. His cognitive and verbal abilities made him a unique case in that he responded favourably to therapeutic instructions regarding relaxation and self-control tactics. The therapists were able to rely on K.'s verbalizations and feelings about his biting in structuring the treatment approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of a retrovirus encoding human HPRT in mice

Transmissible retroviruses encoding human hypoxanthine phosphoribosyltransferase (HPRT) were used to infect mouse bone marrow cells in vitro, and the infected cells were transplanted into mice. Both active human HPRT-protein and chronic HPRT-virus production were detected in hematopoietic tissue of the mice, showing transfer of the gene. These results indicate the possible use of retroviruses for somatic cell therapy.

Problems in the behavioural treatment of self-injury in the Lesch-Nyhan syndrome

The results are described of a behavioural programme designed to modify self-injurious behaviour of a child with Lesch-Nyhan syndrome. The treatment combined extinction of the injurious behaviour and reinforcement of alternative behaviour, and was successful in the controlled hospital environment. However, an attempt to teach the parents to continue the treatment at home failed. The results are discussed in terms of the possible relationship between organic and environmental factors in maintaining the injurious behaviour, and the importance of analysing both the behaviour itself and the factors (including familial) maintaining it. It is suggested that parents should be advised about management of behavioural problems at an early age.

Behavior therapy for a child with Lesch-Nyhan syndrome

The behavioural symptoms in a 10-year-old boy with Lesch-Nyhan syndrome were effectively ameliorated by the behavior therapy techniques of systematic desensitization and extinction. Therapy was undertaken in a highly controlled environment. The hypothesis that the self-destructive behaviours in this syndrome were voluntary and maintained through continuous reinforcement was confirmed. Characteristic biting and other maladaptive behaviours were extinguished. Over a period of time it was possible to remove all the physical restraints previously used to prevent the boy injuring himself. During treatment his anxiety, associated with phobic reaction to being unrestrained, was reduced by nitrous oxide. At 1 1/2 years follow-up the boy continues to be symptom-free. He attends a special class at school and is learning to walk with crutches. It is emphasied that a trained and experienced therapist and a controlled environment are essential for the success of this form of behaviour therapy, and the dangers inherent in this method of treatment are discussed.