Sudden death in Lesch-Nyhan disease

Management of neurological symptoms in Lesch-Nyhan disease: A systematic review

Lesch-Nyhan Disease (LND) is an X-linked recessive genetic disorder arising from hypoxanthine phosphoribosyltransferase 1 gene mutations, leading to a complete deficiency. LND presents a complex neurological profile characterized by generalized dystonia, motor dysfunctions and self-injurious behavior, which management is challenging. We conducted a systematic review of studies assessing the efficacy of pharmacological and non-pharmacological interventions in management of neurological symptoms in LND (PROSPERO registration number:CRD42023446513). Among 34 reviewed full-text papers; 22 studies were rated as having a high risk of bias. Considerable heterogeneity was found in studies regarding the timing of treatment implementation, adjunctive treatments and outcome assessment. Single-patient studies and clinical trials often showed contradictory results, while therapeutic failures were underreported. S-Adenosylmethionine and Deep Brain Stimulation were the most studied treatment methods and require further research to address inconsistencies. The evidence from levodopa studies underlines that optimal timing of treatment implementation should be thoroughly investigated. Standardized study design and reducing publication bias are crucial to overcome current limitations of assessing intervention efficacy in LND.

Delayed emergence from propofol anesthesia in a patient with Lesch-Nyhan syndrome: A case report

RATIONALE

Lesch-Nyhan syndrome (LNS) is an X-linked recessive disorder presenting with uric acid overproduction, neurocognitive disability, and behavioral disturbances. Inhalational anesthesia has been frequently used in LNS patients undergoing surgery. Characteristic compulsive self-injurious behavior and high risk of emesis may hinder inhalational induction. Propofol may be beneficial for these patients because of its easy and rapid titration for anesthetic depth during induction, early recovery from anesthesia, and antiemetic effect as well as uricosuric effect.

PATIENT CONCERNS

A 16-year-old male adolescent was scheduled for percutaneous nephrolithotomy. He exhibited poorly controlled muscle, self-injurious behaviors and intellectual disability.

DIAGNOSIS

The patient presented with neurodevelopmental delay in the first year of life, and was diagnosed with LNS, with a substitution of phenylalanine to leucine in hypoxanthine-guanine phosphoribosyltransferase (HPRT) 1 gene on the X-chromosome at 3 years of age.

INTERVENTIONS

Total intravenous anesthesia was used for induction and maintenance of anesthesia with propofol and remifentanil using target-controlled infusion.

OUTCOMES

Time to recovery of consciousness was prolonged after uneventful surgery. Serum uric acid levels gradually increased during postoperative period.

LESSONS

Propofol anesthesia using target-controlled infusion does not provide significant clinical advantages in rapid emergence from anesthesia and management of hyperuricemia in LNS patients undergoing urological surgery.

Phenotypic and molecular spectrum of Korean patients with Lesch-Nyhan syndrome and attenuated clinical variants

Lesch-Nyhan syndrome (LNS) is an X-linked recessive disorder caused by mutations in the HPRT1 gene. The clinical features and mutation spectrum of 26 Korean LNS patients from 23 unrelated families were retrospectively reviewed. The HPRT1 gene was analyzed by direct sequencing of genomic DNA. The median age at diagnosis was 2.3 years (range, 4 months-22.6 years) and the initial presenting features included developmental delay, orange colored urine, and self-injurious behaviors. Most patients were wheelchair-bound and suffered from urinary complications and neurologic problems such as self-mutilation and developmental delay. Twenty different mutations in HPRT1 were identified among 23 independent pedigrees, including six novel mutations. The most common mutation type was truncating mutations including nonsense and frameshift mutations (45%). Large deletions in the HPRT1 gene were identified in exon 1, exons 5-6, exons 1-9, and at chr X:134,459,540-134,467,241 (7702 bp) including the 5'-untranslated region, exon 1, and a portion of intron 1. In conclusion, this study describes the phenotypic spectrum of LNS and has identified 20 mutations from 23 Korean families, including six novel mutations in Korean patients with LNS.

Clinical, biochemical and genetic characteristics of a cohort of 101 French and Italian patients with HPRT deficiency

BACKGROUND

HPRT deficiency is a rare disorder of purine metabolism whose natural history is not fully understood. No optimal management recommendations exist. The objective of the present study is to characterize a large cohort of patients with HPRT deficiency, comparing Lesch-Nyhan Disease (LND) and its attenuated variants, with the purpose of helping clinicians in disease management and prognostic definition.

METHODS

Genetic and clinical features of French and Italian patients with a confirmed diagnosis of HPRT deficiency were collected.

RESULTS

A hundred and one patients were studied, including 66 LND, 22 HND (HPRT-related Neurological Dysfunction) and 13 HRH (HPRT-Related Hyperuricemia) patients. The clinical manifestations at onset were not specific, but associated with an orange coloration of diapers in 22% of patients. The overall neurological involvement was more severe in LND than in HND patients. Behavioural disturbances were not limited to self-injuries and were not exclusive of LND. Median age of involuntary movements and self-injuries appearance in LND was 1.0 and 3 years, respectively. Renal manifestations (66.3% of patients) occurred at any age with a median onset age of 1.1 years, while gout (25.7% of patients) appeared later in disease course (median onset age 18 years) and was more frequent in attenuated variants than in LND. HPRT activity and genotype showed a significant correlation with the severity of the neurological disease. On the contrary, there were no significant differences in the development of nephropathy or gout. For the treatment of neurological aspects, botulinum toxin injections, oral or intrathecal baclofen and gabapentin were partially efficacious and well tolerated, while deep brain stimulation was associated to a worsening of patients' condition.

CONCLUSIONS

The present study improves the knowledge of the natural history of HPRT deficiency and could represent a starting point for the development of future management guidelines.

Lesch-Nyhan disease: A rare disorder with many unresolved aspects

Lesch-Nyhan Disease (LND) is a rare X-linked recessive metabolic and neurological syndrome due to the deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT). Besides its well known “housekeeping” function this purine salvage enzyme has revealed an unexpected role in neurodevelopment, unveiled by the peculiar neurological symptoms flanking hyperuricemia in LND: dystonia, choreoathetosis, compulsive self-injurious behaviour. Several lines of research have tried to find the molecular basis for the neurological phenotype after the disease was first described in 1964. Dopaminergic deficit was then found to underlie the neurologic symptoms but the aetiology for such alteration seemed inexplicable. A number of detailed studies in the last 50 years addressed the genetic, metabolic, cognitive, behavioral and anatomical features of this disease. Initial investigations seeked for accumulation of toxic metabolites or depletion of essential molecules to disclose potential connections between purine recycling and neuronal dysfunction. In the last two decades sophisticated biotechnological methods were used for a deeper insight in the genetic and molecular aspects, unveiling a network of combined gene dysregulations in neuronal development and differentiation producing neurotransmission defects. These studies, conducted with several different approaches, allowed consistent steps forward, demonstrating transcriptional aberrations affecting different metabolic pathways in HPRT deficiency, yet leaving many questions still unsolved.

Lesch-Nyhan syndrome: The saga of metabolic abnormalities and self-injurious behavior

Lesch-Nyhan syndrome (LNS) is an X-linked recessive disorder of purine metabolism caused by a mutation in Xq26.2-q26.3 (OMIM 308000.0004). The presence of the diagnostic triad, i.e. signs of self-injurious behavior (SIB) and results of pedigree analysis and novel molecular biology & genetic testing, confirms the diagnosis of LNS. With a level of hypoxanthine guanine phosphoribosyl-transferase 1 (HPRT1) enzyme activity < 2%, patients develop neurological, neurocognitive, and neuromotor symptoms along with SIB. Described here is a case of 4-year-old boy who was diagnosed with LNS. The boy displayed SIB, i.e. biting of the lips and fingers, and he had cerebral venous sinus thrombosis caused by LNS.

Severe Respiratory Acidosis in Status Epilepticus as a Possible Etiology of Sudden Death in Lesch-Nyhan Disease: A Case Report and Review of the Literature

INTRODUCTION

Lesch-Nyhan disease (LND) is an X-linked disorder of purine metabolism, associated with self-mutilation, dystonia, and chorea. Seizures are uncommon in LND. Patients with LND are at risk for sudden and unexpected death. The etiology of this is unknown, but appears to occur from a respiratory process. We propose that respiratory failure secondary to subclinical seizure may lead to sudden death in these patients.

CASE

We report a case of an 11-year-old boy with LND who had two episodes of nocturnal gasping. The second event was immediately followed by a 10 min generalized seizure. Upon arrival at the hospital, an arterial blood gas test revealed a severe respiratory acidosis. Following aggressive treatment of his seizures, this patient did well, and was discharged home on oxcarbazepine with rectal diazepam. No further seizures have been noted in 1 year of follow-up.

CONCLUSIONS

In this case report and review, we hypothesize that sudden death from respiratory failure in Lesch-Nyhan disease may in some cases be due to seizure-induced respiratory failure, akin to sudden unexpected death in epilepsy (SUDEP). We suggest screening for paroxysmal respiratory events; consideration of electroencephalography for patients with LND presenting in respiratory distress or failure; and consideration of more aggressive treatment of seizures in these patients. Brief Summary:We present an 11-year-old boy with Lesch-Nyhan disease (LND) who developed respiratory failure and severe respiratory acidosis from his first known seizure, which evolved to subclinical status epilepticus. We propose that patients with LND have a predisposition to respiratory failure and sudden death, which in some cases may be provoked by seizure (sudden unexpected death in epilepsy, or SUDEP).

Lesch-Nyhan Syndrome: Disorder of Self-mutilating Behavior

Lesch-Nyhan syndrome (LNS), a rare inborn error of metabolism, is characterized by self-injurious behavior, which results in partial or total destruction of oral and perioral tissues and/ or fingers. Persistent self-injurious behavior (biting the fingers, hands, lips, and cheeks; banging the head or limbs) is a hallmark of the disease. Prevention of self-mutilation raises significant difficulties. A case of a 10-month-old boy with aggressive behavior and severe lower lip injuries is presented. How to cite this article: Jathar P, Panse AM, Jathar M, Gawali PN. Lesch-Nyhan Syndrome: Disorder of Self-mutilating Behavior. Int J Clin Pediatr Dent 2016;9(2):139-142.

The Effect of S-Adenosylmethionine on Self-Mutilation in a Patient with Lesch-Nyhan Disease

BACKGROUND

Lesch-Nyhan disease (LND) is an X-chromosomal disorder of purine metabolism characterized by hyperuricemia, dystonia, and self-mutilation, leading to an extremely high burden of disease in affected patients and families. Although allopurinol therapy can control hyperuricemia, it has no effect on self-mutilation and neurological symptoms. Single reports describe a beneficial effect of S-adenosylmethionine (SAM) on the neurological symptoms, which motivated us to evaluate this alternative treatment.

METHODS

We performed a double-blind placebo-controlled trial to analyze the effects of SAM on self-mutilation attempts in a male patient affected by LND. The trial lasted for 282 days and comprised three alternating verum and placebo periods of 50 days each. The mother of the patient recorded attempts of self-mutilation during the entire trial.

RESULTS

While verum and placebo were both well tolerated, a total of 1,762 events of self-mutilation were recorded, of which 1,281 events were in the placebo period and 481 in the verum period. The daily mean of events was 8.6 with placebo and 4.5 with SAM corresponding to a 50 % decrease in self-mutilation events under SAM treatment (p < 0.05).

CONCLUSION

The results of this double-blind placebo-controlled single-case trial suggest that SAM can have a beneficial effect on self-mutilation in patients with LND, possibly by replenishing the purine pool in affected brain cells.

Small Duplication of HPRT 1 Gene May Be Causative For Lesh-Nyhan Disease in Iranian Patients

Deficiency of hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is a rare inborn error of purine metabolism and is characterized by uric acid overproduction along with a variety of neurological manifestations that depend on a degree of the enzymatic deficiency. Inheritance of HPRT deficiency is X-linked recessive; thus, males are generally more affected and heterozygous females are carriers (usually asymptomatic). Human HPRT is encoded by a single structural gene on the long arm of the X chromosome at Xq26. More than 300 mutations in the HPRT1 gene have been detected. Diagnosis can be based on clinical and biochemical findings as well as enzymatic and molecular testing. Molecular diagnosis is the best way as it allows for faster and more accurate carrier and prenatal diagnosis. In this report, a new small duplication in the HPRT1 gene was found by sequencing, which has yet to be reported.

Fuzzy optimization for detecting enzyme targets of human uric acid metabolism

MOTIVATION

Mathematical modeling and optimization have been used for detecting enzyme targets in human metabolic disorders. Such optimal drug design methods are generally differentiated as two stages, identification and decision-making, to find optimal targets. We developed a unified method named fuzzy equal metabolic adjustment to formulate an optimal enzyme target design problem for drug discovery. The optimization framework combines the identification of enzyme targets and a decision-making strategy simultaneously. The objectives of this algorithm include evaluations of the therapeutic effect of target enzymes, the adverse effects of drugs and the minimum effective dose (MED).

RESULTS

An existing generalized mass action system model of human uric acid (UA) metabolism was used to formulate the fuzzy optimization method for detecting two types of enzymopathies: hyperuricemia caused by phosphoribosylpyrophosphate synthetase (PRPPS) overactivity and Lesch-Nyhan syndrome. The fuzzy objectives were set so that the concentrations of the metabolites were as close as possible to the healthy levels. The target design included a diet control of ribose-5-phospahate (R5P). The diet control of R5P served as an extra remedy to reduce phosphate uptake entering the purine metabolic pathway, so that we could obtain a more satisfactory treatment than obtained for those without a diet control. Moreover, enhancing UA excretion resulted in an effective treatment of hyperuricemia caused by PRPPS overactivity. This result correlates with using probenecid and benbromazone, which are uricosuric agents present in current clinical medications. By contrast, the Lesch-Nyhan syndrome required at least three enzyme targets to cure hyperuricemia.

A population study of Lesch-Nyhan disease in the UK

AIM

The aims of this study were to identify all people with Lesch-Nyhan disease (LND) born in the UK between 1988 and 2008, and to obtain a clinical profile including age at diagnosis, genetic background, family history, neurological signs, and medications.

METHOD

Potential participants were contacted through the British Paediatric Neurology Surveillance Unit. Questionnaires were sent to each child's paediatric neurologist or primary consultant. Two purine laboratories provided metabolic information.

RESULTS

Twenty-three live males with LND in the 0- to 20-year age band and eight live males over the age of 20 years were identified. Thirty-one live people with LND were identified in the UK in 2008, giving a prevalence of 1 in 2 million people. Over the 20 years of study, there was a mean incidence rate of 0.18 per 100 000 live births, range 0 to 0.5.

INTERPRETATION

To our knowledge, this study is the first to provide details of the prevalence and incidence of LND in the UK. The data highlight that clinical profiles, at the time of diagnosis, and management of the disease are variable. There is the need for ongoing monitoring of allopurinol dosage and metabolic screening.

Hypoxanthine-guanine phosophoribosyltransferase (HPRT) deficiency: Lesch-Nyhan syndrome

Deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity is an inborn error of purine metabolism associated with uric acid overproduction and a continuum spectrum of neurological manifestations depending on the degree of the enzymatic deficiency. The prevalence is estimated at 1/380,000 live births in Canada, and 1/235,000 live births in Spain. Uric acid overproduction is present inall HPRT-deficient patients and is associated with lithiasis and gout. Neurological manifestations include severe action dystonia, choreoathetosis, ballismus, cognitive and attention deficit, and self-injurious behaviour. The most severe forms are known as Lesch-Nyhan syndrome (patients are normal at birth and diagnosis can be accomplished when psychomotor delay becomes apparent). Partial HPRT-deficient patients present these symptoms with a different intensity, and in the least severe forms symptoms may be unapparent. Megaloblastic anaemia is also associated with the disease. Inheritance of HPRT deficiency is X-linked recessive, thus males are generally affected and heterozygous female are carriers (usually asymptomatic). Human HPRT is encoded by a single structural gene on the long arm of the X chromosome at Xq26. To date, more than 300 disease-associated mutations in the HPRT1 gene have been identified. The diagnosis is based on clinical and biochemical findings (hyperuricemia and hyperuricosuria associated with psychomotor delay), and enzymatic (HPRT activity determination in haemolysate, intact erythrocytes or fibroblasts) and molecular tests. Molecular diagnosis allows faster and more accurate carrier and prenatal diagnosis. Prenatal diagnosis can be performed with amniotic cells obtained by amniocentesis at about 15–18 weeks' gestation, or chorionic villus cells obtained at about 10–12 weeks' gestation. Uric acid overproduction can be managed by allopurinol treatment. Doses must be carefully adjusted to avoid xanthine lithiasis. The lack of precise understanding of the neurological dysfunction has precluded development of useful therapies. Spasticity, when present, and dystonia can be managed with benzodiazepines and gamma-aminobutyric acid inhibitors such as baclofen. Physical rehabilitation, including management of dysarthria and dysphagia, special devices to enable hand control, appropriate walking aids, and a programme of posture management to prevent deformities are recommended. Self-injurious behaviour must be managed by a combination of physical restraints, behavioural and pharmaceutical treatments.