Punishment learning and self-mutilation in Lesch-Nyhan disease

Description of the Lesch-Nyhan neurobehavioral disorder and its management through participant observation of three young individuals

Background

Lesch-Nyhan disease (LND; OMIM 300322), caused by virtually absent hypoxanthine-guanine phosphoribosyltransferase activity, in its classic form is characterised by hyperuricemia, variable cognitive impairment, severe motor disorder and a characteristic behavioural disorder (Lesch-Nyhan Behavior, LNB), typically described as self-injurious behavior (SIB) and "self-mutilation." This work focuses on the latter aspect with the aim of exploring and broadening it.

Methods

The participant observation method was used to follow three children diagnosed with LND individually, in different contexts of daily life, always with their usual restraints and in the presence of a caregiver.

Results

60 observational sessions, for over 90 total hours, led to the description of 292 LNBs, interfering with different aspects of life. Harmful behaviors could be classified into different categories, based on the life aspect affected and type of harm provoked. Antecedent conditions, consequent reactions, and emotions of the child and different management of the caregiver were recorded for each LNB. We confirmed that patients normally feel pain. Most common emotional reactions are regret and shock. As a consequence of a LNB, increased anxiety was always recorded, never satisfaction. Caregiver strategies most commonly used to stop the LNB and preventing recurrences are reported and discussed.

Conclusions

We are proposing a wider LNB description, beyond the classical Self-injurious behavior (SIB), stating that it is widespread and pervasive, involving every facet of the patients' life. Caregivers and operators should be aware that they might face different LNBs, and have to recognize them to find the better way to manage patients.

Scoping review of symptoms in children with rare, progressive, life-threatening disorders

BACKGROUND

Q3 conditions are progressive, metabolic, neurological or chromosomal childhood conditions without a cure. Children with these conditions face an unknown lifespan as well as unstable and uncomfortable symptoms. Clinicians and other healthcare professionals are challenged by a lack of evidence for symptom management for these conditions.

AIMS

In this scoping review, we systematically identified and mapped the existing literature on symptom management for children with Q3 conditions. We focused on the most common and distressing symptoms, namely alertness, behavioural problems, bowel incontinence, breathing difficulties, constipation, feeding difficulties, sleep disturbance, temperature regulation, tone and motor problems and urinary incontinence. For children with complex health conditions, good symptom management is pertinent to ensure the highest possible quality of life.

METHODS

Scoping review. Electronic database searches in Ovid MEDLINE, Embase and CINAHL and a comprehensive grey literature search.

RESULTS

We included 292 studies in our final synthesis. The most commonly reported conditions in the studies were Rett syndrome (n=69), followed by Cornelia de Lange syndrome (n=25) and tuberous sclerosis (n=16). Tone and motor problems were the most commonly investigated symptom (n=141), followed by behavioural problems (n=82) and sleep disturbance (n=62).

CONCLUSION

The evidence for symptom management in Q3 conditions is concentrated around a few conditions, and these studies may not be applicable to other conditions. The evidence is dispersed in the literature and difficult to access, which further challenges healthcare providers. More research needs to be done in these conditions to provide high-quality evidence for the care of these children.

Lesch-Nyhan syndrome and its variants: examining the behavioral and neurocognitive phenotype

PURPOSE OF REVIEW

Lesch-Nyhan Syndrome (LNS) is a metabolic disorder involving mutations in the HGPRT1 gene that result in hyperuricemia, intellectual disability, a dystonic movement disorder, and compulsive self-injury with self-mutilation. The aim of this review is to summarize recent research that documents the extended behavioral, neurologic, and neurocognitive phenotype in classic LNS, to describe milder variants of HGprt deficiency that do not self-injure and have less severe neurological and cognitive deficits, and to provide an update on treatment for associated psychiatric and behavioral disorders.

RECENT FINDINGS

Psychiatric management utilizes combined behavioral and pharmacological treatment in conjunction with protective equipment and dental management to avert self-injury. Pharmacological management focuses on stabilization of mood and anxiety management. S-adenosylmethionine (SAMe), a physiological intermediate in methylation and transsulfuration, has shown beneficial effects in carefully selected patients who can tolerate the drug. Deep brain stimulation is shown in several case reports and series to reduce or eliminate self-injury and aggression, and in some cases, modify dystonia.

SUMMARY

This review highlights progress in our understanding of the behavioral and neurocognitive phenotype of Lesch-Nyhan syndrome (HGprt deficiency) and its variants, describes psychiatric and behavioral management, and discusses prospects for new therapies.

Development of new forms of self-injurious behavior following total dental extraction in Lesch-Nyhan disease

We report two Lesch-Nyhan Disease (LND) patients who developed new forms of self-injurious behavior following total dental extraction. Patients 1 and 2 were submitted to total teeth extraction at the age of 13 and 8 years, respectively, due to continuous self-biting, not prevented by mouth guards. Severity of dystonia was markedly reduced and quality of life improved. After 12 and 17 months, respectively, patient 1 started rubbing one foot against other and scratching toenails with his hands, and patient 2 stuck his legs and feet against hard objects. These forms of self-injury behavior could be easily prevented with protective materials, according to the mothers.

Consequences of Delayed Dental Extraction in Lesch-Nyhan Disease

Patients with Lesch-Nyhan disease (LND) often engage in self-injurious biting. This problem requires difficult management choices, sometimes including removal of the teeth. Although many health care professionals are reluctant to remove teeth in a child because of the permanent negative cosmetic consequences of the edentulous state, disfigurement of the face and tongue from self-biting can be worse. We analyzed the records of 5 LND patients who used mouth guards to spare the teeth. Success was variable, and dental extraction ultimately was required in 4 cases. We also reviewed previously published cases on the use of dental devices to spare teeth in LND. Various devices have been recommended, but failure rates are high, and tooth extraction often is still needed. Although dental extraction is not required in all cases, it should not be delayed when biting is severe.

Working with People with Learning Difficulties Who Self-Injure: A Review of the Literature

Self-injurious behaviour in people with learning difficulties has been found to be a common and health-threatening problem. As a consequence, there is an expanding literature addressing a variety of methods of intervention that are either designed to facilitate or to enforce the reduction or extinction of such behaviour. It is not clear, however, the extent to which such interventions are successful in achieving their avowed goal. This paper critically reviews the treatment of self-injurious behaviour, including work which takes psychodynamic, psychopharmacological, developmental, self-stimulation or learned behaviour perspectives, in order to establish the current status of interventions in this area. It is concluded that no single treatment approach has been shown to be effective in facilitating a reduction in the self-injurious behaviour of all clients. Rather, individualized programmes of intervention need to be constructed, using careful causal and functional analyses of behaviour. Moreover, such programmes, which may be multi-modal in nature, need to aim for interventions that are minimally or non-aversive.

Annotation: behavioural phenotypes: a window onto the biology of behaviour

Characteristic behavioural patterns (including cognitive processes and social interactions) have been reported in a number of syndromes arising from genetic or chromosomal abnormalities, suggesting that molecular analysis of the underlying defect could reveal the biological basis of the behavioural phenotype. Because of the rarity of many of the syndromes, and the complexity of their genetic basis, there are great difficulties in establishing the validity of the association between syndrome and behavioural phenotype. Nevertheless, evidence from animal studies with relevance to human behavioural phenotypes shows that the pathway from genotype to phenotype may be accessible by careful delineation of behavioural phenotypes.

Self-injury in Lesch-Nyhan disease

Parents of 40 patients with Lesch-Nyhan disease completed a questionnaire detailing developmental history, life course, management, medication, factors influencing variability and topography of self-injury. Several conclusions were reached. Characteristics: Biting was the predominant form, perhaps only because of the difficulty of preventing it. There was considerable variability in self-injury which was strongly related to stress rather than to operant influences. Even though patients could not inhibit self-injury they could predict it and request restraints. Aggression against others was as prevalent as self-injury.

MANAGEMENT

Stress reduction, teeth extraction, and physical restraint were the most commonly used management techniques. Behavior modification was of limited efficacy. Benzodiazepines were the most commonly used medications for controlling self-injury.

OUTCOME

The severity of self-injury did not change over years. Age of onset was a predictor of outcome. The earlier the age of onset the worse the self-injury eventually became. The discussion describes research strategies, suggests dimensions along which self-injury can be classified, and highlights behavior not commonly described in patients with Lesch-Nyhan disease.

Defects of tetrahydrobiopterin synthesis and their possible relationship to a disorder of purine metabolism (the Lesch-Nyhan syndrome)

The metabolic pathways of pterin de novo synthesis, interconversion and salvage which lead to the tetrahydrobiopterin cofactor of phenylalanine 4-monooxygenase, tyrosine 2-monooxygenase and tryptophan 5-monooxygenase are reviewed and data on the enzymes which catalyze the individual steps are presented. Analogies drawn between the inborn errors of tetrahydrobiopterin production and the Lesch-Nyhan syndrome, in which purine salvage is deficient, are used as a basis for the hypothesis that the neurological manifestations of the Lesch-Nyhan syndrome are due to neurotransmitter imbalance which stems from an imbalance of the aromatic amino acid monooxygenase activities which are themselves due to impaired pterin biosynthesis. The latter arises because, in the absence of the hypoxanthine phosphoribosyltransferase catalyzed purine salvage pathway, the supply of GTP for the GTP cyclohydrolase reaction, which is the first reaction on the pterin de novo synthesis pathway, is reduced. It is proposed that the different aromatic amino acid monooxygenases are differentially affected by this constrained pterin production. The activities of those most directly related to the quantal production of the cerebral neurotransmitters dopamine, norepinephrine and 5-hydroxytryptamine are affected whereas liver phenylalanine 4-monooxygenase activity is not overtly impaired. The results of different lines of research which support this concept are cited, as is direct evidence for a selective reduction of dopamine production in the basal ganglia of patients with the Lesch-Nyhan syndrome. It is proposed that lack of GMP for functions, other than its role in pterin de novo synthesis, accounts for the features of the Lesch-Nyhan syndrome which do not occur when only tetrahydrobiopterin production is deficient as in the inborn errors of tetrahydrobiopterin synthesis.

Lesch-Nyhan disease: clinical experience with nineteen patients

The clinical phenotype in Lesch-Nyhan disease has been analyzed in 19 patients studied in hospital. In each case the diagnosis was made on the basis of inactivity of the enzyme hypoxanthine guanine phosphoribosyltransferase in erythrocyte lysates. All had hyperuricemia, and the presence of 'orange sand' in the diaper was a prominent early complaint. All had self-mutilative behavior, of which the most characteristic form was biting the fingers or lips. All had the neurological syndrome of spasticity and choreoathetoid involuntary movements. All but one had less-than-normal intelligence.

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.