Lesch-Nyhan Research Articles

LESCH NYHAN SYNDROME- UNUSUAL PRESENTATION- A CASE REPORT

Lesch Nyhan Syndrome (LNS) is a rare hereditary disorder with an incidence of 1 in 380,000. It is a condition characterized by neurological and behavioral abnormalities and uric acid over production in the body. The authors here report a case where developmental delay, a common presentation was complicated by presence of pathological jaundice in neonatal period. It was further complicated by parents shifting to another country and lost to follow up. By the time case was diagnosed and parental counseling was done, mother was already pregnant and 20 weeks into her 2nd pregnancy and abortions were prohibited by law in that country. It is unfortunate that 2nd child is also a male child who is affected.

An electrochemical biosensor based on multi-wall carbon nanotube–modified screen-printed electrode immobilized by uricase for the detection of salivary uric acid

The amounts of uric acid (UA) in non-invasive biological samples, such as saliva, are critical for diagnosis and therapy of gout, hyperuricemia, Lesch-Nyhan syndrome, and several other diseases. Here, disposable UA biosensors were fabricated with the screen printing technique on the substrate of flexible PET. The working electrode was modified with carbon nanotubes followed by uricase for UA detection with excellent selectivity. The biosensor showed good electrocatalytic activity toward UA with high sensitivity, low detection limit, and wide linear range, which covers the full range of UA levels in human saliva. We demonstrate that UA can be directly detected in human saliva with the biosensor and the experimental data were consistent with the clinical analysis. This study indicated that the non-invasive biosensor is an attractive and possible approach for the monitoring of salivary UA. Graphical abstract A disposable uric acid biosensor modified with carbon nanotubes followed by uricase was fabricated on flexible PET and applied for the monitoring of salivary uric acid in human saliva.

Lesch-Nyhan Syndrome: Evaluation of a Modified Bite Device to Prevent Bite Injuries

Lesch-Nyhan syndrome (LNS) is a serious form of hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency, a hereditary purine metabolism disorder. The prevalence reported in the literature is 1/380,000 to 235,000 births. Males are affected and females are heterozygous carriers. LNS patients present a combination of hypotonia, spasticity, and neurological and behavioral disorders. They also show an obsessive-compulsive self-injurious behavior with bites and injuries to the lips, tongue, cheeks and fingers. The literature offers little scientific contribution related to the management of this problem. The authors describe their experience with a 4-year-old LNS patient and present a viable solution to control and avoid bite injuries, namely a specifically modified bite. The patient was treated at the Pediatric Dentistry Department of “Sapienza” University of Rome with a modified bite with the internal surface, in contact with the teeth, realized in 2-mm-thick soft silicone, and the exterior part consisting of a transparent resin shell with front and rear shields to separate lips and cheeks from the dental arches. At a 12-month follow-up visit, compliance was excellent: the child wore the device with regularity and without discomfort, even during soft-food feeding. No intraoral bite injuries were found, with a general improvement of the young patient’s quality of life.

Physiological levels of folic acid reveal purine alterations in Lesch-Nyhan disease

Lesch-Nyhan disease (LND), caused by a deficient salvage purine pathway, is characterized by severe neurological manifestations and uric acid overproduction. However, uric acid is not responsible for brain dysfunction, and it has been suggested that purine nucleotide depletion, or accumulation of other toxic purine intermediates, could be more relevant. Here we show that purine alterations in LND fibroblasts depend on the level of folic acid in the culture media. Thus, physiological levels of folic acid induce accumulation of 5-aminoimidazole-4-carboxamide riboside 5'-monophosphate (ZMP), an intermediary of de novo purine biosynthetic pathway, and depletion of ATP. Additionally, Z-nucleotide derivatives (AICAr, AICA) are detected at high levels in the urine of patients with LND and its variants (hypoxanthine-guanine phosphoribosyltransferase [HGprt]-related neurological dysfunction and HGprt-related hyperuricemia), and the ratio of AICAr/AICA is significantly increased in patients with neurological problems (LND and HGprt-related neurological dysfunction). Moreover, AICAr is present in the cerebrospinal fluid of patients with LND, but not in control individuals. We hypothesize that purine alterations detected in LND fibroblasts may also occur in the brain of patients with LND.

Lesch-Nyhan disease: I. Construction of expression vectors for hypoxanthine-guanine phosphoribosyltransferase (HGprt) enzyme and amyloid precursor protein (APP)

Lesch-Nyhan disease (LND) is a rare X-linked inherited neurogenetic disorder of purine metabolism in which the enzyme, hypoxanthine-guanine phosphoribosyltransferase (HGprt) is defective. Despite having been characterized over 50 years ago, it remains unclear precisely how deficits in HGprt enzyme activity can lead to the neurological syndrome, especially the self-injury of LND. Several studies have proposed different hypotheses regarding the etiology of this disease, and several treatments have been tried in patients. However, up to now, there is no satisfactory explanation of the disease and for many LND patients, efficacious treatment for persistent self-injurious behavior remains unreachable. A role for epistasis between mutated hypoxanthine phosphoribosyltransferase 1 (HPRT1) and amyloid precursor protein (APP) genes has been recently suggested. This finding may provide new directions not only for investigating the role of APP in neuropathology associated with HGprt-deficiency in LND but also for the research in neurodevelopmental and neurodegenerative disorders in which the APP gene is involved in the pathogenesis of diseases and may pave the way for new strategies applicable to rational antisense drugs design. It is therefore necessary to study the HGprt enzyme and APP using expression vectors for exploring their impacts on LND as well as other human diseases, especially the ones related to APP such as Alzheimer’s disease in which the physiologic function and the structure of the entire APP remain largely unclear until now. For such a purpose, we report here the construction of expression vectors as the first step (Part I) of our investigation.

Nwd1 Regulates Neuronal Differentiation and Migration through Purinosome Formation in the Developing Cerebral Cortex.

SummaryEngagement of neural stem/progenitor cells (NSPCs) into proper neuronal differentiation requires the spatiotemporally regulated generation of metabolites. Purines are essential building blocks for many signaling molecules. Enzymes that catalyze de novo purine synthesis are assembled as a huge multienzyme complex called “purinosome.” However, there is no evidence of the formation or physiological function of the purinosome in the brain. Here, we showed that a signal transduction ATPases with numerous domains (STAND) protein, NACHT and WD repeat domain-containing 1 (Nwd1), interacted with Paics, a purine-synthesizing enzyme, to regulate purinosome assembly in NSPCs. Altered Nwd1 expression affected purinosome formation and induced the mitotic exit and premature differentiation of NSPCs, repressing neuronal migration and periventricular heterotopia. Overexpression/knockdown of Paics or Fgams, other purinosome enzymes, in the developing brain resulted in a phenocopy of Nwd1 defects. These findings indicate that strict regulation of purinosome assembly/disassembly is crucial for maintaining NSPCs and corticogenesis.

SUN-462 Lesch-Nyhan syndrome: A Case Report

Lesch-Nyhan syndrome, a rare inborn error of metabolism, characterized by Hyperuricemia, Spectrum of neurological dysfunctions, and Cognitive and behavioral disturbances, is a rare anomaly caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyl transferase-1 (HGPRT-1), produced by mutations in the HPRT gene located on the X-chromosom leading to the overproduction of purine and accumulation of uric acid. There is no medical treatment to alleviate the symptoms of self-mutilation except dental intervention. The disease affects mainly male child, and females are asymptomatic carriers. We report a case of a 13 year old male child from Ethiopia, Who presented with Worsening of self-injurious behavior and failure to pass urine of 03 days duration. Initially presented with rigidity of the extremities at the age of 4 months and later neck rigidity with intermittent arching of the back. Family noticed passage of whitish grit like material in urine. He had poor appetite, irritability and poor weight gain. For the above complains he was diagnosed to have CP and advised to have physiotherapy. For lack of improvement, family discontinued follow-up. At the age of 3 years, he started to experience a self-injurious behavior by biting initially his lips and subsequently his hands and upper arms with ulceration of the lips and loss of finger nails and later developed head banging and rubbing of the extremities against the floor and nearby object. He developed aggression to his family with biting and pinching. Subsequently started on Clonazepam and Trihexyphenidyl with the diagnosis of dystonic CP, which showed slight improvement. Resperidone was started for the self-injurious behavior, On current presentation, he had poor feeding, low grade intermittent fever, worsening of passage of whitish stone via urine and worsening of self-injurious behavior. He has had recurrent chest and urinary tract infections. His mom and uncle have knee pain and she is taking Allopurinol. There is no history consanguinity in the family. The delivery was in hospital at term, and had uneventful perinatal history. He is the 2nd child to the family, fully vaccinated with adequate nutritional history. Brothers are 17 and 7 years old, grade 10 and 3 students, both apparently healthy. On examination, he is chronically sick looking, irritable. He is severely wasted, stunted and BMI was 17.1. He has ulcerated lips with tissue loss, ulcerated tongue (anterior 2/3 tongue and ulcerated and sloughed nail beds. On CNS he is conscious with intact Cranial nerves; Motor shows wasted muscle bulk but comparable on both sides. Power was 3/5 and had increased tone in all extremities. The DTR was 2/4 in ankle and knee. Plantar reflex was equivocal and there was no clonus or meningeal signs. Sensation to pain and touch was intact. He was admitted and bilateral percutaneous nephrostomy was inserted to relieve ureteric obstruction and medically managed for UTI, multiple electrolyte abnormality due to GI and urinary loss. The AKI resolved with standing ESKD due to obstructive uropathy following nephrolithiasis. In pediatric patients, self-mutilation is seen in genetic syndromes like LNS, Cornelia de Lange, Gilles de la Tourette syndrome, mental retardation, encephalitis, congenital malformation. A careful evaluation is, essential toward making the appropriate diagnosis of LNS.

Неспецифический остеомиелит позвоночника (НОП) у пациента с первичной подагрой на фоне синдрома Леша–Найхана (СЛН): описание клинического случая и обзор литературы

Неспецифический остеомиелит позвоночника (НОП) у пациента с первичной подагрой на фоне синдрома Леша–Найхана (СЛН): описание клинического случая и обзор литературы

Semi-Fixed Lip Bumper in Lesch-Nyhan Syndrome: An Interim Treatment Modality

Lesch-Nyhan syndrome is a rare X-linked, recessively inherited disorder of purine metabolism, caused by complete absence of the enzyme hypoxanthine-guanine phosphoribosyl transferase. This syndrome is characterized by 3 major features: neurological dysfunction, hyperuricemia, and cognitive and behavioral disturbances (e.g., self-mutilation, which begins at 2 to 3 years of age). Uncontrollable self-mutilation begins with biting of the perioral tissues and extends into patterns such as finger biting and head hitting. This report describes the case of a 31-month-old boy who was diagnosed with Lesch-Nyhan syndrome with severe lip injuries caused by self-mutilative behaviors. The behaviors were blocked with a semi-fixed lip bumper for a short period. The device was applied to the patient on the day of the visit without the requirement for an oral impression. It was easy to manage oral hygiene and adjust the device because it was detachable by clinicians and guardians. Therefore, a semi-fixed lip bumper may be useful as an interim appliance to block self-mutilative behaviors in children with Lesch-Nyhan syndrome.

Rescuing compounds for Lesch-Nyhan disease identified using stem cell–based phenotypic screening

Lesch-Nyhan disease (LND) is a rare monogenic disease caused by deficiency of the salvage pathway enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). LND is characterized by severe neuropsychiatric symptoms that currently cannot be treated. Predictive in vivo models are lacking for screening and evaluating candidate drugs because LND-associated neurological symptoms are not recapitulated in HGPRT-deficient animals. Here, we used human neural stem cells and neurons derived from induced pluripotent stem cells (iPSCs) of children affected with LND to identify neural phenotypes of interest associated with HGPRT deficiency to develop a target-agnostic-based drug screening system. We screened more than 3000 molecules and identified 6 pharmacological compounds, all possessing an adenosine moiety, that corrected HGPRT deficiency-associated neuronal phenotypes by promoting metabolism compensations in an HGPRT-independent manner. This included S-adenosylmethionine, a compound that had already been used as a compassionate approach to ease the neuropsychiatric symptoms in LND. Interestingly, these compounds compensate abnormal metabolism in a manner complementary to the gold standard allopurinol and can be provided to patients with LND via simple food supplementation. This experimental paradigm can be easily adapted to other metabolic disorders affecting normal brain development and functioning in the absence of a relevant animal model.

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

BackgroundLesch‐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.MethodsThe 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.Results60 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.ConclusionsWe 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.

Chromosome Transplantation: A Possible Approach to Treat Human X-linked Disorders

Many human genetic diseases are associated with gross mutations such as aneuploidies, deletions, duplications, or inversions. For these “structural” disorders, conventional gene therapy, based on viral vectors and/or on programmable nuclease-mediated homologous recombination, is still unsatisfactory. To correct such disorders, chromosome transplantation (CT), defined as the perfect substitution of an endogenous defective chromosome with an exogenous normal one, could be applied. CT re-establishes a normal diploid cell, leaving no marker of the procedure, as we have recently shown in mouse pluripotent stem cells. To prove the feasibility of the CT approach in human cells, we used human induced pluripotent stem cells (hiPSCs) reprogrammed from Lesch-Nyhan (LN) disease patients, taking advantage of their mutation in the X-linked HPRT gene, making the LN cells selectable and distinguishable from the resistant corrected normal cells. In this study, we demonstrate, for the first time, that CT is feasible in hiPSCs: the normal exogenous X chromosome was first transferred using an improved chromosome transfer system, and the extra sex chromosome was spontaneously lost. These CT cells were functionally corrected and maintained their pluripotency and differentiation capability. By inactivation of the autologous HPRT gene, CT paves the way to the correction of hiPSCs from several X-linked disorders.

Lesch-Nyhan syndrome. Case report and review of literature

Lesch-Nyhan syndrome. Case report and review of literature

A Case of Applying a Mouthguard with Lower Lip Exclusion to Prevent Self-injurious Behavior to the Lower Lip for a Patient with Lesch-Nyhan Syndrome

A Case of Applying a Mouthguard with Lower Lip Exclusion to Prevent Self-injurious Behavior to the Lower Lip for a Patient with Lesch-Nyhan Syndrome

Animal Model Contributions to Congenital Metabolic Disease.

Genetic model systems allow researchers to probe and decipher aspects of human disease, and animal models of disease are frequently specifically engineered and have been identified serendipitously as well. Animal models are useful for probing the etiology and pathophysiology of disease and are critical for effective discovery and development of novel therapeutics for rare diseases. Here we review the impact of animal model organism research in three examples of congenital metabolic disorders to highlight distinct advantages of model system research. First, we discuss phenylketonuria research where a wide variety of research fields and models came together to make impressive progress and where a nearly ideal mouse model has been central to therapeutic advancements. Second, we review advancements in Lesch-Nyhan syndrome research to illustrate the role of models that do not perfectly recapitulate human disease as well as the need for multiple models of the same disease to fully investigate human disease aspects. Finally, we highlight research on the GM2 gangliosidoses Tay-Sachs and Sandhoff disease to illustrate the important role of both engineered traditional laboratory animal models and serendipitously identified atypical models in congenital metabolic disorder research. We close with perspectives for the future for animal model research in congenital metabolic disorders.

Clinical outcome of prenatally suspected cardiac rhabdomyomas of the fetus.

Background The main objective of this retrospective analysis in a large tertiary center was the clinical outcome of prenatally diagnosed cardiac rhabdomyomas as well as the identification of factors influencing fetal prognosis. Methods A total of 45 cases of fetuses with prenatally suspected rhabdomyoma and their clinical outcome were analyzed retrospectively. A review of the literature was also performed. Results In five cases, after a tuberous sclerosis complex (TSC) mutation had been confirmed, termination of pregnancy was chosen. In 30 cases postnatal data were available. In 93% TSC was confirmed clinically or by mutational analysis. Two thirds of fetuses presented with multiple tumor while one third presented with a solitary tumor. In two fetuses mild pericardial effusions were observed. Another three fetuses presented with extrasystoles prenatally. No hydrops fetalis or fetal perinatal demise were observed. After birth 41% of the children suffered from arrhythmia including supra- and ventricular tachycardia, Wolff-Parkinson-White syndrome and atrioventricular block. One child received a Fontan procedure with Glenn anastomosis. Another child with a dilatative cardiomyopathy and a left ventricular ejection fraction of 15% died. Fifty-two percent of the children with TSC suffered from epilepsy ranging from absence epilepsy and West syndrome to generalized seizures with a frequency of up to 40 per day. Two children underwent neurosurgery to remove the epileptogenic focus. One child suffered from TSC and Lesch-Nyhan disease. In another case Beckwith-Wiedemann syndrome was identified as the causative disorder. Conclusion Rhabdomyoma are rare, benign tumors. There is an association with TSC. In the majority of cases rhabdomyoma are not hemodynamically relevant and do not increase in size. The quality of life of affected patients is impaired particularly due to epilepsy and psychomotor retardation.

223 Lesch-Nyhan syndrome: from patient to mouse model

Abstract Introduction. HPRT1 is a Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) coding gene, mutations of which cause, among other diseases, Lesch-Nyhan syndrome. LNS is a severe X-linked recessive neurological disorder. Alignment shows 98.6% homology of human and murine protein sequences. Objectives. We assume that murine model of this human disease should be developed. So, our purpose is to create a transgenic mouse model of Lesch-Nyhan syndrome by CRISPR/Cas9 genome editing system. Methods. The BLAST was used to find homologous mutation in murine HPRT1 gene comparing to Human one. X-ray crystallographic structural model of the HPRT1 was used as template for M4T Raptor algorithm to generate predicted structure of mutated protein. Models were visualized in PyMol (Schrodinger, Portland, OR). Lack of enzymatic activity of the HGPRT could be caused via troubled homodimerization. Absence of the aliphatic Valine could be the reason of the hindered monomers interaction. Genetic construction based on the px330 plasmid was brought using microinjection method in mouse fertilized ovum for producing primary transgenic organisms. Results. The CRISPR/Cas9 system was specifically designed to carry out mutations in HPRT. The resulting genetic construct was introduced into the fertilized mouse ovum to obtain primary transgenic organisms. This mouse was obtained at the Institute of Biology of the Russian Academy of Sciences. Conclusion. Homologous mutation in human and murine HPRT1 gene resulting into comparable conformational change in the protein model structure was revealed, so murine personalized model of the Lesch-Nyhan syndrome could be developed. Structural changes can be further studied to provide treatment strategy for people suffering from Lesch-Nyhan syndrome. This study was supported by Russian Science Foundation (Grant #17-75-20249).

Generation of cell strains containing point mutations in HPRT1 by CRISPR/Cas9

Mutations in Hypoxanthine-guanine Phosphoribosyltransferase1 (HPRT1) gene can lead to metabolic disorder of hypoxanthine and guanine metabolism, and other severe symptoms such as hypophrenia, gout, and kidney stones, called the Lesch-Nyhan disease (LND). Although the mutations are widely distributed throughout the HPRT1 gene, there are some isolated hot spots. In this study, we aim to introduce two previously reported hot spots, c.508 C>T and c.151 C>T, which could lead to premature translational termination in HPRT1 gene. Through CRISPR/Cas9 mediated homology-directed repair (HDR) by using single-stranded oligo-deoxyribonucleotides (ssODN) as donor template, we obtained cell clones containing these two mutations in HEK293T or HeLa cells. Targeted mutation of c.508 C>T and c.151 C>T reached to 16.3% and 10%, respectively. We further detect HPRT1 protein levels with Western blot and enzyme activity with 6-TG in 5 different cell clones. HPRT1 protein and its enzymatic activity both was hardly detected in homozygous mutant cells, while reduced HPRT1 protein expression and enzymatic activity was detected in heterozygous mutant cells. Our study will be beneficial to those who working on generation of cell or animal models of HRPT1 mutations, and provides a basis for further investigations on the genetic mechanism of Lesch-Nyhan disease.

Clinical features and genetic analysis of Lesch-Nyhan syndrome caused by HPRT1 gene mutation in one child

对北京儿童医院神经内科诊断的1例HPRT1基因突变致Lesch-Nyhan综合征患儿的临床资料进行回顾性分析。患儿，男，1岁2个月，因自幼发育落后就诊。体质量9.2 kg，头围44.0 cm，身长75.0 cm，兴奋时易全身用力，上下肢不自主舞动，面部表情刻板，流涎，竖头不稳，右上肢屈曲，手握拳，主动取物手指伸展困难，动作僵硬，1岁4个月出现频繁不自主咬手指，尿有机酸分析示尿酸增高(2.431 mmol/mmolCrn)。患儿及其父母外周血DNA进行全外显子组测序，结果示患儿携带X染色体HPRT1基因c.134G>A(p.Arg45Lys)半合子变异，经Sanger验证发现该变异遗传自患儿母亲。予低嘌呤饮食，加用别嘌呤醇片每次1/8片，每日2次，口服10 d后复查血尿酸降至正常水平。提示临床上如有发育落后、肌张力障碍并尿酸升高、自伤症状的患儿，应考虑Lesch-Nyhan综合征的可能。

Reduced Graphene Oxide-based Covalent Hybrid Film Electrode Self-assembled with Gold Nanoparticles for the Enzyme-Free Amperometric Sensing of Serum Uric Acid.

Purine metabolism in the human body leads to the production of uric acid (UA) at the end. But an abnormal level of UA in the human body creates health problems. The sensing and quantification of UA is essentially required to prevent and diagnose hypertension, arthritis, gout, hyperuricemia or Lesch-Nyhan syndrome, etc. Herein, the development of a sensing platform for the measurement of UA using Au nanoparticle-based hybrid self-assembly is described. The self-assembling of a thiol-terminated silicate network functionalized graphene oxide hybrid on a polycrystalline Au surface yields a three-dimensional assembly. The oxygen functionalities of the self-assembly were partially reduced by an NaBH4 treatment. The free -SH groups of the self-assembly were successfully used for the immobilization of Au nanoparticles by chemisorption. The nanoparticle-based hybrid self-assembly is highly sensitive toward UA, and shows a wide linear response with a detection limit of 40 nM UA (S/N = 7) without interference from co-exiting ascorbic acid. Its practical application was demonstrated using human serum samples.