Case series of patients under biweekly treatment with laronidase: a report of a single center experience / Série de casos de pacientes em tratamento com laronidase quinzenal: relato da experiência de um centro

ABSTRACT Objective: To report the stabilization of urinary glycosaminoglicans (GAG) excretion and clinical improvements in patients with mucopolysaccharidosis type I (MPS I) under an alternative dose regimen of laronidase of 1.2 mg/kg every other week. Methods: We participated in a dose-optimization trial for laronidase in MPS-I patients using four alternative regimens: 0.58 mg/kg every week, 1.2 mg/kg every two weeks, 1.2 mg/kg every week and 1.8 mg/kg every other week (EOW). After the trial ended, the patients resumed the recommended dose and regimen of 0.58 mg/kg every week. Under this regimen, some patients presented difficulties in venous access and were unable to commute weekly to the treatment center. Therefore, we used an alternative regimen that consisted of 1.2 mg/kg EOW in eight patients. A retrospective study of medical records of MPS-I patients who underwent both enzyme replacement therapy (ERT) regimens, of 0.58 mg/kg every week and 1.2 mg/kg EOW, was done. Results: Patients remained clinically stable under the alternative regimen, did not present elevation of urinary GAG nor any adverse event. Conclusions: The switch of dose regimen to 1.2 mg/kg EOW of laronidase was safe, and did not cause any clinical worsening in patients who had been previously under standard dose ERT.

RESUMO Objetivo: Descrever a manutenção dos níveis de glicosaminoglicano (GAG) excretados na urina e da estabilização clínica em pacientes com mucopolissacaridose do tipo I (MPS I) com o uso da laronidase num regime de dose alternativo de 1,2 mg/kg a cada duas semanas. Método: Alguns pacientes do nosso serviço participaram de um estudo de otimização de dose da laronidase para o tratamento da MPS I no qual foram comparados quatro esquemas terapêuticos: 0,58 mg/kg/semana, 1,2 mg/kg a cada duas semanas, 1,2 mg/kg/semana e 1,8 mg/kg a cada duas semanas. Após o término do estudo, todos os pacientes passaram a receber a terapia de reposição enzimática (TRE) na dose padrão de bula, que é de 0,58 mg/kg/semana, e nesse regime alguns pais se queixaram da dificuldade em comparecer ao centro todas as semanas, além da dificuldade de se obter acesso para punção venosa. Com base nessas queixas, oito pacientes passaram a receber a TRE no regime alternativo de 1,2 mg/kg a cada duas semanas. Foi feito o estudo retrospectivo de dados de prontuário de pacientes com MPS I que fizeram TRE com laronidase nas doses 0,58 mg/kg/semana e 1,2 mg/kg a cada duas semanas. Resultados: Os pacientes mantiveram-se clinicamente estáveis, não apresentaram aumento dos níveis de GAG urinários nem eventos adversos durante o regime alternativo de dose. Conclusões: A mudança para o esquema de 1,2 mg/kg de laronidase a cada duas semanas foi segura e não acarretou piora clínica nos pacientes que já estavam em TRE na dose padrão.

Laronidase como terapia de reposição enzimática na mucopolissacaridose tipo I / Laronidase as enzyme replacement therapy in mucopolysaccharidosis type I

CONTEXTO: A mucopolissacaridose tipo I (MPS I) é uma doença lisossômica (DL) crônica, progressiva, causada pela atividade deficiente da alfa-L-iduronidase (IDUA). A IDUA é responsável pela clivagem dos resíduos de ácido idurônico dos glicosaminoglicanos (GAGs) heparan e dermatan sulfato. Na MPS I, ocorre o acúmulo desses GAGs parcialmente degradados no interior dos lisossomos e o aumento da sua excreção na urina. Em consequência, os pacientes apresentam comprometimento dos sistemas respiratório, nervoso, musculoesquelético, gastrointestinal (fígado e baço), cardiovascular, dentre outros. A MPS I é herdada de forma autossômica recessiva, sendo uma doença rara. A sua incidência mundial é bastante variável, sendo estimada entre 0,69 e 1,66 por 100.000 pessoas. Está associada a três formas clássicas, que diferem entre si com base na presença de comprometimento neurológico, na velocidade de progressão da doença e na gravidade do acometimento dos órgãos-alvo. Não existe tratamento curativo para a MPS I. O manejo clínico dos pacientes envolve equipe multidisciplinar e inclui intervenções realizadas no nível do fenótipo clínico (como cirurgias para correção de hérnias) e no nível da proteína mutante (transplante de células hematopoiéticas (TCTH) e terapia de reposição enzimática (TRE), conduzida com laronidase, enzima produzida por tecnologia de DNA recombinante). TECNOLOGIA: Laronidase. INDICAÇÃO: Reposição enzimática na mucopolissacaridose tipo I. PERGUNTA: O uso da laronidase como TRE em pacientes com MPS tipo I é eficaz e seguro na melhora clínica e da qualidade de vida dos pacientes? EVIDÊNCIAS CIENTÍFICAS: Foram realizadas buscas nas seguintes bases de dados: PubMed, Embase, Lilacs, Cochrane e ClinicalTrials.gov. Treze estudos foram incluídos nesse relatório, sendo nove ensaios clínicos controlados e randomizados, 4 revisões sistemáticas, os quais foram avaliados pelos desfechos, classificados, por sua vez, como de maior ou menor relevância clínica no tratamento da doença. Dentre os quatro desfechos considerados de maior relevância avaliados, o tratamento com laronidase trouxe benefício clinicamente significativo na capacidade de flexão do ombro que reflete um efeito positivo nas doenças osteoarticulares. Para os outros desfechos avaliados, qualidade de vida, manifestações cardiológicas e doença ocular não foi possível determinar com precisão a existência de benefício. Entre os desfechos de menor relevância, o uso de laronidase demonstrou ter impacto benéfico na diminuição da excreção de GAGs urinários e diminuição do crescimento hepático, mas com efeito incerto na capacidade respiratória, e no crescimento e estado nutricional. O uso de laronidase foi considerado seguro, não se relatando efeitos adversos importantes que pudessem comprometer o tratamento. Em estudos não controlados ou randomizados observaram-se maior probabilidade de sobrevida e menor impacto em órgãosalvo em participantes que fizeram o tratamento de reposição enzimática, principalmente quando se iniciava o tratamento de forma mais precoce. Recomendam-se que sejam implementadas políticas de saúde e educacionais no Brasil, que permitam o diagnóstico precoce dos pacientes, a fim de possibilitar a realização de TCTH, quando indicado, o início precoce da TRE e o aconselhamento genético. Da mesma forma, Protocolo Clínico e Diretrizes Terapêuticas deve estabelecer os critérios para início e interrupção do tratamento. ANÁLISE DE IMPACTO ORÇAMENTÁRIO: A estimativa de impacto orçamentário decorrente da incorporação de laronidase estaria entre R$ 29 milhões a R$ 44 milhões no primeiro ano de incorporação. RECOMENDAÇÃO INICIAL: A CONITEC recomendou preliminarmente a incorporação no SUS da laronidase para reposição enzimática em pacientes com mucopolissacaridose tipo I. CONSULTA PÚBLICA: Foram recebidas 348 contribuições, sendo 340 pelo formulário de experiência ou opinião e 8 pelo formulário técnico-científico. No que diz respeito às características das 340 contribuições pelo formulário de experiência ou opinião analisadas, 337 contribuições foram de pessoa física e 3 de pessoa jurídica. O percentual de concordância com a recomendação da CONITEC foi de 100%. Dos 08 formulários técnico-cientifico enviados e analisados, 7 foram de pessoa física (4 de profissionais de saúde, 2 interessados e 1 familiar) e 1 de pessoa jurídica. Todas as 8 contribuiçoes recebidas pelo formulário técnico-científico se declaravam favoráveis à recomendação da CONITEC e apenas 1 apresentou argumentos ciêntíficos. DELIBERAÇÃO FINAL: Os membros presentes na 57ª reunião do Plenário da CONITEC, nos dias 5 e 6 de julho, deliberaram por unanimidade recomendar a incorporação da laronidase para reposição enzimática em pacientes com mucopolissacaridose tipo I. Foi assinado o Registro de Deliberação nº 275/2017.(AU)

IDUA gene mutation analysis and prenatal diagnosis of two families affected with mucopolysaccharidosis type I / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze mutations of IDUA gene in two pedigrees affected with mucopolysaccharidosis type I and provide prenatal diagnosis for them.</p><p><b>METHODS</b>The 14 exons of the IDUA gene were subjected to PCR amplification and Sanger sequencing.</p><p><b>RESULTS</b>For pedigree 1, the proband was found to harbor compound heterozygous mutations c.46-57delTCGCTCCTGGCC (p.Ser16_Ala19del) of exon 1 and c.1147delC (p.Arg383Alafs*57) of exon 8 of the IDUA gene, which were inherited from his father and mother, respectively. The latter was unreported previously. Prenatal diagnosis suggested that the fetus has carried a heterozygous c.46-57delTCGCTCCTGGCC mutation. For family 2, the proband was also found to carry compound mutations of the IDUA gene, namely c.721T to C (p.Cys241Arg) of exon 6 and c.1491delG (p.Thr497fs27) of exon 8, which were inherited from her mother and father, respectively. Neither mutation was reported previously. Prenatal diagnosis suggested that the fetus has carried a heterozygous c.721T to C mutation.</p><p><b>CONCLUSION</b>Mutations of the IDUA gene probably underlie the MPS-I in both pedigrees. Above results have enriched the spectrum of IDUA gene mutations and facilitated prenatal diagnosis for both families.</p>

Long-term restoration of alpha-L-iduronidase activity in fibroblasts from patients with mucopolysaccharidosis type I after non-viral gene transfer

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder caused by deficiency of alpha-L-iduronidase (IDUA). Limitations such as the need for weekly injections, high morbidity and mortality, and high cost of current treatments show that new approaches to treat this disease are required. In this study, we aimed to correct fibroblasts from a patient with MPS I using non-viral gene therapy. Using a plasmid encoding the human IDUA cDNA, we achieved stable high IDUA levels in transfected fibroblasts up to 6 months of treatment. These results serve as proof of concept that a non-viral approach can correct the enzyme deficiency in cells of patients with lysosomal storage disorders, which can be used as a research tool for a series of disease aspects. Future studies should focus on showing if this approach can be useful in small animals and clinical trials (AU)

The impact of laronidase treatment in otolaryngological manifestations of patients with mucopolysaccharidosis / Impacto do tratamento com laronidase nas manifestações otorrinolaringológicas de pacientes com mucopolissacaridose

ABSTRACT INTRODUCTION: Mucopolysaccharidosis (MPS) is a lysosomal storage disease caused by deficiency of a-l-iduronidase. The otolaryngological findings include hearing loss, otorrhea, recurrent otitis, hypertrophy of tonsils and adenoid, recurrent rhinosinusitis, speech disorders, snoring, oral breathing and nasal obstruction. OBJECTIVE: To evaluate the impact of enzymatic replacement therapy with laronidase (Aldurazyme(r)) in patients with mucopolysaccharidosis (MPS I), regarding sleep and hearing disorders, and clinical manifestations in the upper respiratory tract (URT). METHODS: Nine patients with MPS I (8 Hurler-Scheie, and 1 Scheie phenotypes) of both sexes, ages ranging between 3 and 20 years, were included in this study. Patients were evaluated between seven and 11 months before the treatment and between 16 and 22 months after the onset of the enzymatic replacement. They were all submitted to a clinical and otolaryngological evaluation, including nasofibroscopical, polysomnographic and audiologic exams. RESULTS: The results' data showed decreasing of the frequency of ear, nose and throat infections, with improvement of the rhinorrhea and respiratory quality. No remarkable changes were observed regarding macroglossia and tonsil and adenoid hypertrophy. Audiometric and polysomnographic evaluations did not show statistical significance. CONCLUSION: Enzymatic replacement therapy in patients with mucopolysaccharidosis I provides control of recurrent URT infections, rhinorrhea and respiratory quality, however it is does not seem to improve audiologic and polisomnographic parameters, with no effect on adenoid and tonsils hypertrophy and macroglossia.

Resumo Introdução: Mucopolissacaridose (MPS) é uma doença de depósito lisossômico causada pela deficiência de a-l-iduronidase. Os achados otorrinolaringológicos incluem perda auditiva, otorreia, otites de repetição, hipertrofia adenotonsilar, rinossinusite recorrente, distúrbios da fala, roncos, respiração bucal e obstrução nasal. Objetivo: Avaliar o impacto da terapia de reposição enzimática com laronidase (Aldurazyme(r)) em pacientes com mucopolissacaridose I (MPS I) em relação ao sono, distúrbios auditivos e manifestações clínicas do trato respiratório superior (TRS). Método: Nove pacientes com MPS I (oito com fenótipo Hurler-Scheie e um com fenótipo Scheie), de ambos os sexos, com idades variando entre 3 e 20 anos, foram incluídos neste estudo. Os pacientes foram avaliados entre 7 e 11 meses antes do tratamento e entre 16 e 22 meses após o início da substituição enzimática. Todos foram submetidos a uma avaliação clínica e otorrinolaringológica, incluindo nasofibroscopia, polissonografia e exames radiológicos. Resultados: Os dados dos resultados mostraram diminuição da frequência de infecções de orelha, nariz e garganta, com melhora da rinorreia e da qualidade respiratória. Mudanças significativas não foram observadas em relação à macroglossia e à hipertrofia adenotonsilar. Avaliações audiométricas e polissonográficas não apresentaram significância estatística. Conclusão: A terapia de reposição enzimática em pacientes com mucopolissacaridose I fornece controle de infecções recorrentes do TRS, rinorreia e qualidade respiratória, porém, não parece melhorar os parâmetros audiológicos e polissonográficos, ou exercer efeito sobre a hipertrofia adenotonsilar e macroglossia.

Tratamiento de mucopolisacaridosis tipo I con trasplante de células madre de sangre de cordón umbilical de donante no emparentado: informe del primer caso exitoso en Colombia / Treatment of mucopolysaccharidosis I with cord blood stem cell transplantation of unrelated donor: report of first successful case in Colombia

Resumen: se presenta el primer caso exitoso en Colombia de trasplante de células madre de sangre de cordón umbilical no relacionadas, en un niño de 30 meses de edad con diagnóstico de mucopolisacaridosis tipo I. El paciente fue recibido a los seis meses de edad por presentar signos y síntomas típicos de la enfermedad, por lo que se realizó confirmación diagnóstica por bioquímica y se determinó la mutación genética. Se inició terapia de reemplazo enzimático con laronidasa a los 13 meses de edad y se llevó a cabo un trasplante de sangre de cordón umbilical de un donante no emparentado a los 30 meses, alcanzando una sobrevida superior a los tres años con mejoría en el neurodesarrollo y cambios fenotípicos marcados, sin evidencia de cifosis, macrocefalia y macroglosia, entre otros. El control ecocardiográfico actual es normal, sin manejo farmacológico, evidencia de cifosis, macrocefalia o macroglosia. Como se reporta en la literatura, el trasplante de células madre de sangre de cordón umbilical de donante no emparentado es una alternativa efectiva y segura en el tratamiento de esta enfermedad.

Abstract: here we present the first successful case in Colombia of transplantation of unrelated cord blood stem cell transplantation in a 30-month-old boy diagnosed with mucopolysaccharidosis type I. Patient was received at the age of six months showing typical signs and symptoms of the disease. Biochemical diagnosis was confirmed and the genetic mutation was determined. Patient began enzymereplacement therapy with laronidase at the age of 13 months and, at the age of 30 months he underwent cord blood stem cell transplantation. The boy reaching more than three years of survival with neurologic progression with marked phenotypic changes, decrease of coarse facies, active, walking without help, with normal echocardiography results without medication, no evidence of kyphosis, macrocephaly and macroglossia. In this case, it is evident that transplantation of unrelated hematopoietic stem cells from cord blood is an effective and safe alternative in treating Hurler syndrome.

A Simple and Rapid Method Based on Liquid Chromatography-Tandem Mass Spectrometry for the Measurement of alpha-L-Iduronidase Activity in Dried Blood Spots: An Application to Mucopolysaccharidosis I (Hurler) Screening

BACKGROUND: We developed an analytical method to measure alpha-L-iduronidase (IDUA) activity in dried blood spots. This was achieved by using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with electrospray ionization in the positive ion mode. METHODS: Chromatographic separation was completed using mobile phase involving water-formic acid and acetonitrile-formic acid over 2.8 min of run time on a column with a Kinetex XB-C18 (Phenomenex, USA). The detection of column effluent was performed using a Xevo TQ-S triple quadrupole mass spectrometer (Waters, USA) in the multiple-reaction monitoring mode. This method was verified with blank and control samples at four activity levels: base, low, medium, and high. Control materials were provided from Centers for Disease Control and Prevention (CDC). RESULTS: Intra- and inter-day precisions were between 2.6% and 16.5% and between 7.9% and 17.0%, respectively. A correlative regression study on the IDUA activity in CDC-control samples performed to assess the validity of the developed method showed a highly significant linear association (r2=0.9976) between the calculated and CDC-reported values and an obvious difference in activity among the four levels. This reliable analytical method was applied to mucopolysaccharidosis I (Hurler) screening of patients under treatment (n=4) and in normal controls (n=129). IDUA activity ranged from 8.98 to 77.12 micromol/hr/L) in normal controls, and patients undergoing medical treatment showed low IDUA activity. CONCLUSIONS: This method had advantages of simplicity, rapid sample preparation, and liquid chromatographic separation, which efficiently inhibited ionization suppression induced by matrix effects in mass spectrometric detection.

Mutation c.1190-1delG/N in intron 8 and c.1708G>C/N in exon 12 not reported in the IDUA gene developed a clinical phenotype of Scheie syndrome / Mutación c.1190-1delG/N en el intrón 8 y c.1708G>C/N en el exón 12 no reportada en el gen de IDUA desarrolló un fenotipo clínico de síndrome de Scheie

Mucopolysaccharidoses are a group of lysosomal storage disorders caused by deficiency of enzymes catalyzing the degradation of glycosaminoglycans. Mucopoly-saccharidosis I can present a wide range of phenotypic characteristics with three major recognized clinical entities: Hurler and Scheie syndromes represent phenotypes at the severe and mild ends of the clinical spectrum, respectively, and the Hurler-Scheie syndrome is intermediate in phenotypic expression. These are caused by the deficiency or absence of α-L-iduronidase, essential to the metabolism of both dermatan and heparan sulfate, and it is encoded by the IDUA gene. We report the case of a 34-year-old male patient with enzymatic deficiency of α-L-iduronidase, accumulation of its substrate and a previously unreported mutation in the IDUA gene that developed a phenotype of Scheie syndrome.

Las mucopolisacaridosis son un grupo de trastornos de almacenamiento lisosomal causada por la deficiencia de enzimas que catalizan la degradación de glicosaminoglicanos. La mucopolisacaridosis tipo I puede presentar un amplio rango de características fenotípicas englobadas en tres entidades clínicas reconocidas: los síndromes de Hurler y Scheie representan los fenotipos graves y leves del espectro clínico, respectivamente y el síndrome de Hurler-Scheie intermedio en la expresión fenotípica. Estos son causados por la deficiencia o ausencia de la α-L-iduronidasa esencial para el metabolismo del dermatán y el heparán sulfato y es codificada por el gen IDUA. Se presenta el caso de paciente masculino de 34 años de edad con deficiencia enzimática de α-L-iduronidasa, acumulación de su sustrato y una mutación en el gen IDUA, no reportada previamente, que desarrolló un fenotipo del síndrome de Scheie.

A terapia de reposição enzimática pode mudar a frequência de intervenções médicas na mucopolissacaridose tipo I? Um estudo retrospectivo e exploratório / Can enzyme replacement therapy change the frequency of medical interventions in mucopolysaccharidosis type I? An exploratory retrospective study

Introdução: A mucopolissacaridose tipo I (MPS I) é uma doença lisossômica (DL) para a qual está disponível a terapia de reposição enzimática (TRE) com laronidase. Objetivo: caracterizar o efeito da TRE em pacientes com MPS I avaliados por um único centro de referências para DL a partir da análise da frequência de intervenções médicas. Métodos: Estudo retrospectivo e exploratório com comparações pré e pós-intervenção. O número/ano/paciente de consultas, medicamentos usados, internações, cirurgias e exames realizados, foi obtido por meio de revisão de prontuário médico. Essas variáveis foram, então, comparadas entre dois períodos: pré-TRE e pós-TRE. Resultados: Nove pacientes (graves=3, atenuados=6) foram incluídos no estudo. A mediana de idade de início da TRE foi 9 anos e a mediana de duração da TRE foi 4 anos. Em média, os pacientes realizaram 90% das infusões previstas para o período. Somente o número de cirurgias/ano/paciente foi dependente do tempo de doença (p=0,0004) e da gravidade do fenótipo (p=0,014). Com relação às comparações pré e pós-TRE, as variáveis que apresentaram diferença significativa (média do número/ano/paciente) foram: exames (pré-TRE=10,2±2,7; pós-TRE=22,5±2,1; p=0,005) e internações (pré-TRE=0,05±0,04; pós-TRE=0,30±0,11; p=0,013). Conclusão: Nossos dados sugerem que a TRE não alterou a história natural da MPS I em relação aos desfechos analisados. Este achado pode ser devido à idade relativamente avançada de início do tratamento no nosso centro.

Background: Mucopolysaccharidosis type I (MPSI) is a lysosomal disorder (LSD) which can be treated with enzyme replacement therapy (ERT) with laronidase. Aim: To describe the effect of ERT on MPSI patients evaluated at a single referral center for LSD by assessing the frequency of medical interventions. Methods: An exploratory, retrospective study with pre- and post-intervention assessments. We reviewed medical records to collect data on the number of medical appointments/year/patient, medications used, hospital admissions, surgeries, and exams performed. These variables were then compared between the pre- and the post-ERT periods.Results: Nine patients (severe=3; attenuated=6) were included in the study.The median age for the start of ERT was 9 years, and the median time on ERT was 4 years. On average, patients received 90% of the infusions predicted for the study period. Only the number of surgeries/year/patient was found to be dependent on length of disease (p=0.0004) and on severity of phenotype (p=0.014). Regarding pre- and post-ERT comparisons, there was a significant difference (mean number/year/patient in exams (pre-ERT, 10.2±2.7; post-ERT, 22.5±2.1; p=0.005) and hospital admissions (pre-ERT, 0.05±0.04; post-ERT, 0.30±0.11; p=0.013). Conclusion: Our data suggest ERT didn’t alter the natural history of MPSI the outcomes assessed in this study. This may be due to the relatively advanced age of patients when they started treatment at our Center.

Enzymatic diagnosis and clinical characteristics of 52 children with mucopolysaccharidosis / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To explore the incidence of various types of mucopolysaccharidosis (MPS) and their clinical characteristics.</p><p><b>METHODS</b>A total of 75 children highly suspected as having MPS underwent quantitative and electrophoretic analysis of urinary glycosaminoglycans (GAGs) and enzymatic analysis of seven types of MPS from January 2009 to December 2011. Fluorescence assay was used to measure the activities of α-L-iduronidase, iduronate-2-sulfatase, α-N-acetylglucosaminidase, galactosamine-6-sulfatase, β-galactosidase, arylsulfatase B and β-glucuronidase in the white blood cells.</p><p><b>RESULTS</b>A total of 52 cases were confirmed with MPS based on clinical, radiological, and enzymatic examinations. The 52 cases, with a mean age of 4.0 ± 2.2 years, included 5 cases of MPS I (10%), 20 cases of MPS II (38%), 20 cases of MPS IVA (38%), 6 cases of MPS VI (12%) and 1 case of MPS VII (2%). No MPS IV B cases or MPS IIIB cases were found. Compared with healthy children of the same age, the GAG/Cr ratio was significantly elevated in 50 confirmed cases of MPS (two MPS IVA cases having no increased ratio). All children with increased urinary GAGs had a confirmed diagnosis of MPS. The age of onset was between 1 and 2 years after birth in most cases, and often complicated by hernia and valvular heart disease. Children with MPS I, MPS II, and MPS VI presented with ugly and unsmooth face, short stature, joint stiffness, and limitation of motion, while children with MPS IVA presented with short stature, skeletal dysplasia, and joint laxity.</p><p><b>CONCLUSIONS</b>Type IVA and type II are the most common in MPS cases, followed by type VI and type I. MPS children are characterized by special appearances including ugly and unsmooth facial appearance, short stature and skeletal dysplasia. Quantitative analysis of urinary GAG, as a simple, rapid, and reliable method, is recommended for screening of MPS.</p>

Mutation analysis of 11 Chinese patients with attenuated mucopolysaccharidosis type / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disease resulting from the deficiency in the lysosomal enzyme alpha-L-iduronidase (IDUA). The present study was conducted to identify IDUA gene mutations in attenuated (MPS I H/S and MPS I S) patients with MPS I in northern China.</p><p><b>METHODS</b>Fourteen exons with adjacent intronic sequences of the IDUA gene in 11 MPS I patients were amplified by polymerase chain reaction (PCR), and the PCR products were sequenced directly and origin analysis was conducted.</p><p><b>RESULTS</b>Seven mutations were detected in the 11 MPS I patients, i.e., c.236 C to T (p. A79V), c.266 G to A (p.R89Q), c.265 C to T (p.R89W), c.532G to A (p.E178K), c.589G to A (p.G197S), c.1037T to G (p.L346R), and c.1877 G to A (p.W626X). All of them were known mutations. Six patients were homozygotes and 1 was heterozygote with nonsense mutation. In addition, 9 reported single nucleotide polymorphism (SNP) were detected, i.e., p.A8, p.A20, p.H33Q, p.R105Q, p.A314, p. A361T, p.T388, p.T410 and p.V454I.</p><p><b>CONCLUSION</b>The mutation spectrum of the IDUA gene in attenuated MPS I Chinese patients may be different from that in patients from other countries.</p>

Mutation analysis and prenatal diagnosis of 2 cases with mucopolysaccharidosis type I / 中华儿科杂志

<p><b>OBJECTIVE</b>Mucopolysaccharidosis type I (MPS I; MIM# 252800) is an autosomal recessive disease that results from the deficiency in the lysosomal enzyme α-L-iduronidase(IDUA). IDUA is one of the enzymes involved in degradation of glycosaminoglycans heparan sulphate and dermatan sulphate. The deficiency of IDUA leads to widespread accumulation of partially degraded mucopolysaccharides inside lysosomes, resulting in progressive cellular and multiorgan dysfunction. Up to now there is no definitely effective treatment for this disorder, therefore it is important to provide an accurate genetic diagnosis and prenatal diagnosis for the MPSI families. This study was conducted to detect IDUA gene mutation in patients with MPSIand make a definite diagnosis of homozygote or heterozygote and make first trimester prenatal diagnosis.</p><p><b>METHOD</b>The 2 male probands included in this study were diagnosed as MPSI patients in Peking Union Medical College Hospital, case 1 was 2 years old and case 2 was 5 years old. Genomic DNA was extracted from leucocytes in the 2 patients and 2 mothers' cultured amniocytes. IDUA gene DNA sequence was amplified by polymerase chain reaction (PCR) and the PCR products were sequenced directly. Novel mutations were analyzed in 100 normal chromosomes.</p><p><b>RESULT</b>The genotype of case 1 was p.L238R/c.883InsC, while of case 2 was c.531InsT/p.L346R. The fetal case 1 did not inherit the same pathogenic mutations as proband 1, the activity of the IDUA in amniocytes was 9.0 nmol/(h·mg pr). The fetal case 2 inherited the same pathogenic mutations with the proband, the genotype of fetal 2 was c.531InsT/p.L346R, the activity of the IDUA in amniocytes was 0.5 nmol/(h·mg pr).</p><p><b>CONCLUSION</b>Of the 4 mutations found in 2 MPS I patients, p. L238R, c.883InsC, c.531InsT were novel. The fetal case 1 was diagnosed as normal fetus while the fetus 2 was diagnosed as affected. The results of the two kinds of prenatal diagnostic methods were correspondent with each other.</p>

A novel mutation of the alpha-L-iduronidase gene in a patient with mucopolysaccharidosis type I / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the molecular genetic mechanism of a Chinese patient with mucopolysaccharidosis type I (MPS I).</p><p><b>METHODS</b>PCR-sequencing analysis was applied to detect the mutations in exons in alpha-L-iduronidase gene (IDUA) of the patient. Restriction fragment length polymorphism (RFLP) and allele-specific oligonucleotide hybridization (ASO) were used to confirm the identified mutations. PCR amplified DNA samples from 50 normal individuals were sequenced to demonstrate that the newly identified mutation was not polymorphism.</p><p><b>RESULTS</b>The patient was compound heterozygous for a previously reported nonsense mutation Q60X (178C > T) in exon 2, inherited from the mother, and a newly detected missense mutation D203N (607G > A) in exon 6 from the father. The newly identified mutation D203N was not found in PCR amplified products from 50 normal individuals, indicating that it was not polymorphism.</p><p><b>CONCLUSION</b>The two identified mutations may be the cause resulting in patient's clinical phenotype.</p>

Mucopolysaccharidosis type I: clinical and biochemical study

Of 1240 outpatients referred to the Human Genetics Clinic between 1997 and 1998, 248 [20%] had inborn errors of metabolism, 36 [14%] of which were diagnosed as mucopolysaccharidoses. Parental consanguinity was present in 82% of these patients. Deficiency of alpha-L-iduronidase [IDUA] enzyme in leukocytes and increased urinary mucopolysaccharides excretion were detected in 17 patients. The urinary spot test for glucosaminoglycans was inconclusive in 4 of the 17 cases. Results showed a correlation between the biochemical enzyme activity in leukocytes, the amount of excreted mucopolysaccharides and the subtype and course of mucopolysaccharidosis type I. We conclude that estimation of IDUA enzyme activity in leukocytes can differentiate between clinically overlapping cases of MPS I and MPS II and given the clinical manifestations of MPS I is a definitive and unequivocal method of diagnosis while the urinary spot test is inconclusive

Estudio bioquímico de un paciente con enfermedad lisosomal heredometabólica / Biochemical study of a patient with lysosomal inherited metabolic disease

Se reporta el caso de una niña de 18 meses de edad que presenta características fenotípicas de tipo "hurleroide, a la cual se le realizó la determinación de las enzimas relacionadas con el metabolismo de los mucopolisacáridos (MPS), así como la caracterización cinética de la enzima denominada alfa-L-iduronidasa, cuya deficiencia condujo al diagnóstico de dicha enfermedad