Clinical characteristics and treatment of two children with Lesch-Nyhan syndrome
10.3760/cma.j.cn511374-20241010-00527
- VernacularTitle:Lesch-Nyhan综合征患儿2例的临床特点及治疗分析
- Author:
Guang′e YANG
1
;
Conglei SONG
1
;
Fan HE
1
;
Kaili ZHANG
1
;
Bin YANG
1
Author Information
1. 复旦大学附属儿科医院安徽分院（安徽省儿童医院）神经内科，合肥 230052
- Publication Type:Journal Article
- Keywords:
Lesch-Nyhan syndrome;
Developmental disabilities;
Abnormal posture;
Self-injurious behavior;
Hyperuricemia;
Hypoxanthine phosphoribosyltransferase;
HPRT1 va
- From:
Chinese Journal of Medical Genetics
2025;42(6):691-699
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the clinical, genetic, and therapeutic prognostic characteristics of two pediatric cases of Lesch-Nyhan syndrome (LNS) in order to enhance understanding of this disease and investigate more effective treatment strategies.Methods:Clinical data were collected from two children clinically diagnosed with LNS who were treated at Anhui Provincial Children′s Hospital from April 2023 to January 2024. Data were collected retrospectively and included clinical manifestations (symptoms, signs, laboratory and imaging findings), treatment course, and follow-up results. Peripheral venous blood samples (2 mL each) were obtained from children 1 and his parents. Whole-exome sequencing (WES) was performed. Candidate variants were validated by Sanger sequencing to confirm the genetic etiology.Standard bioinformatic analysis of the raw WES data was conducted, including quality control, alignment, variant calling, and annotation. Candidate pathogenic variants were filtered using population frequency databases (e.g., gnomAD), disease databases (e.g., OMIM, ClinVar), and multiple in silico pathogenicity prediction tools (e.g., SIFT, PolyPhen-2, CADD). Phenotype matching was integrated using Human Phenotype Ontology (HPO) terms. Pathogenicity classification of variants was performed according to the American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Interpretation of Sequence Variants (2015). This study was approved by the Medical Ethics Committee of Anhui Children′s Hospital, Children′s Hospital of Fudan University (Approval No.: EYLL-2014-027).Results:Case 1, a 4-year-old boy presented with "developmental delay for over 3 years, accompanied by abnormal postures and involuntary lip-biting". Physical examination revealed limb dystonia, anxious expression, lower lip damage, and communication difficulties. Laboratory tests showed hyperuricemia and renal stones. Genetic testing identified a hemizygote variant in the HPRT1 gene, c. 135G>T (p.Arg45Ser), inherited from an asymptomatic carrier mother, confirming the diagnosis of LNS. This variant was absent from population databases (gnomAD, 1000 Genomes, dbSNP). Protein function prediction tools consistently indicated pathogenic or likely pathogenic variant (SIFT, PolyPhen-2, CADD, and REVEL scores all reached pathogenic thresholds). Protein structural modeling revealed that the mutation disrupts the hydrogen-bonding network, compromising tetramer stability. ACMG classification designated it as likely pathogenic (PM1 + PM2_Supporting + PM5 + PP3). The patient was treated with benhaxol hydrochloride, baclofen, and clonazepam to improve neurological symptoms, and also received treatment with febuxostat in the nephrology department to manage purine metabolism. After one year of follow-up, the patient′s abnormal posture showed slight improvement, self-injurious behavior persisted but was managed with protective gloves, blood uric acid levels normalized, and renal stones decreased. Case 2, a 13-year-old boy was hospitalized in the nephrology department due to a urinary tract infection. Following successful infection treatment, his limb dystonia worsened, leading to his transfer to the neurology ward. The patient had a history of delayed motor and language development, abnormal postures, and lip-biting self-injurious behavior, with elevated blood uric acid levels, leading to an LNS diagnosis. The parents declined genetic testing due to financial constraints. Following discharge, the patient did not adhere to the prescribed medication regimen or attend scheduled outpatient visits. The patient had died by the time of the 4-month follow-up contact. Conclusion:HPRT1 gene variants are the genetic cause of LNS in children, and the HPRT1 gene is the only known pathogenic gene for LNS. Early genetic diagnosis, strict adherence to multidisciplinary comprehensive treatment, and intensive intervention for self-injurious behaviors are crucial for improving the quality of life and prolonging survival in children with LNS.
