Perioperative management of patients with Mucolipidosis II and III: Lessons from a case series.

Mucolipidosis (ML) II and III are complex lysosomal storage disorders characterized by progressive multisystem pathology which can pose challenges to the anesthetist and increase the risks associated with general anesthesia. We sought to review the management of patients with ML II and III undergoing anesthesia in our institution in order to better define recommendations for the preoperative assessment and optimization of these children. We further elected to analyze the conduct of anesthesia, intraoperative management, and perioperative complications that our patients had experienced in order to allow improved informed consent and anesthetic planning. We performed a retrospective examination of the medical notes of those patients who had undergone anesthesia in our institution to identify their clinical features, anesthetic technique, airway management, and perioperative complications. Five children underwent 11 episodes of anesthesia. Fiber-optic or videolaryngoscopy was utilized in six out of seven intubations, with four out of seven requiring a change from the method initially chosen to enable intubation. Four of the five patients had an abnormal echocardiogram. Three patients had radiological evaluation of their cervical spine, with two demonstrating abnormalities. One patient had changes suggesting instability at the atlantoaxial junction. Children and babies with ML II and III present multisystem challenges to the anesthetist. Multidisciplinary planning and assessment, followed by a discussion of risk, should proceed any elective surgery. These complex children should undergo elective anesthesia delivered by an experienced (pediatric) anesthetist in an appropriate tertiary center with on-site pediatric ENT and critical care support.

Molecular Pathways and Respiratory Involvement in Lysosomal Storage Diseases.

Lysosomal storage diseases (LSD) include a wide range of different disorders with variable degrees of respiratory system involvement. The purpose of this narrative review is to treat the different types of respiratory manifestations in LSD, with particular attention being paid to the main molecular pathways known so far to be involved in the pathogenesis of the disease. A literature search was conducted using the Medline/PubMed and EMBASE databases to identify studies, from 1968 through to November 2018, that investigated the respiratory manifestations and molecular pathways affected in LSD. Pulmonary involvement includes interstitial lung disease in Gaucher's disease and Niemann-Pick disease, obstructive airway disease in Fabry disease and ventilatory disorders with chronic respiratory failure in Pompe disease due to diaphragmatic and abdominal wall muscle weakness. In mucopolysaccharidosis and mucolipidoses, respiratory symptoms usually manifest early in life and are secondary to anatomical malformations, particularly of the trachea and chest wall, and to accumulation of glycosaminoglycans in the upper and lower airways, causing, for example, obstructive sleep apnea syndrome. Although the molecular pathways involved vary, ranging from lipid to glycogen and glycosaminoglycans accumulation, some clinical manifestations and therapeutic approaches are common among diseases, suggesting that lysosomal storage and subsequent cellular toxicity are the common endpoints.

Glycosaminoglycan levels in dried blood spots of patients with mucopolysaccharidoses and mucolipidoses.

Mucopolysaccharidoses (MPSs) and mucolipidoses (ML) are groups of lysosomal storage disorders in which lysosomal hydrolases are deficient leading to accumulation of undegraded glycosaminoglycans (GAGs), throughout the body, subsequently resulting in progressive damage to multiple tissues and organs. Assays using tandem mass spectrometry (MS/MS) have been established to measure GAGs in serum or plasma from MPS and ML patients, but few studies were performed to determine whether these assays are sufficiently robust to measure GAG levels in dried blood spots (DBS) of patients with MPS and ML. MATERIAL AND METHODS: In this study, we evaluated GAG levels in DBS samples from 124 MPS and ML patients (MPS I=16; MPS II=21; MPS III=40; MPS IV=32; MPS VI=10; MPS VII=1; ML=4), and compared them with 115 age-matched controls. Disaccharides were produced from polymer GAGs by digestion with chondroitinase B, heparitinase, and keratanase II. Subsequently, dermatan sulfate (DS), heparan sulfate (HS-0S, HS-NS), and keratan sulfate (mono-sulfated KS, di-sulfated KS, and ratio of di-sulfated KS in total KS) were measured by MS/MS. RESULTS: Untreated patients with MPS I, II, VI, and ML had higher levels of DS compared to control samples. Untreated patients with MPS I, II, III, VI, and ML had higher levels of HS-0S; and untreated patients with MPS II, III and VI and ML had higher levels of HS-NS. Levels of KS were age dependent, so although levels of both mono-sulfated KS and di-sulfated KS were generally higher in patients, particularly for MPS II and MPS IV, age group numbers were not sufficient to determine significance of such changes. However, the ratio of di-sulfated KS in total KS was significantly higher in all MPS patients younger than 5years old, compared to age-matched controls. MPS I and VI patients treated with HSCT had normal levels of DS, and MPS I, VI, and VII treated with ERT or HSCT had normal levels of HS-0S and HS-NS, indicating that both treatments are effective in decreasing blood GAG levels. CONCLUSION: Measurement of GAG levels in DBS is useful for diagnosis and potentially for monitoring the therapeutic efficacy in MPS.

Carpal tunnel syndrome and finger deformities in children with mucopolysaccharidoses and mucolipidoses: a retrospective review of 52 patients.

This single-centre retrospective study reports our management of carpal tunnel syndrome in 52 children (103 hands) with mucopolysaccharidoses and mucolipidoses. All except one were bilateral. The median age at surgery was 4 years (range 1.5 to 12). The diagnosis of carpal tunnel syndrome was confirmed by an electromyogram (EMG) in all patients; 38% of these presented without any clinical signs. Surgical neurolysis was performed in all hands, combined with epineurotomy in 52 hands (50%) and flexor tenosynovectomy in 75 hands (73%). Surgery was bilateral in 98% of children (102 hands). The mean follow-up was 12 years (range 1 to 19) and the EMG was normalized in 78% of hands. Ten patients suffered recurrence, eight of whom required further surgery. Screening for carpal tunnel syndrome is essential for the management of children mucopolysaccharidoses and mucolipidoses. Surgical treatment should be carried out early with follow-up by EMG to detect recurrence.Level of evidence: IV.

Genome editing in mucopolysaccharidoses and mucolipidoses.

Mucopolysaccharidoses (MPS) and mucolipidoses (ML) are disorders that alter lysosome function. While MPS are caused by mutation in enzymes that degrade glycosaminoglycans, the ML are disorders characterized by reduced function in the phosphotransferase enzyme. Multiple clinical features are associated with these diseases and the exact mechanisms that could explain such different clinical manifestations in patients are still unknown. Furthermore, there are no curative treatment for any of MPS and ML conditions so far. Gene editing holds promise as a tool for the creation of cell and animal models to help explain disease pathogenesis, as well as a platform for gene therapy. In this chapter, we discuss the main studies involving genome editing for MPS and the prospect applications for ML.

Clinical outcomes of laminoplasty for patients with lysosomal storage disease including mucopolysaccharidosis and mucolipidoses: a retrospective cohort study.

BACKGROUND: Although the clinical efficacy of laminoplasty in adult cervical spondylotic myelopathy or ossification of posterior longitudinal ligament has been frequently reported, there are only few reports of laminoplasty for patients with lysosome storage diseases (LSDs). Therefore, this study aimed to report the midterm clinical and radiological outcomes of patients with LSDs after cervical laminoplasty. METHODS: Six patients with LSD who underwent laminoplasty with/without C1 laminectomy for cervical myelopathy were enrolled. Clinical evaluations, including the cervical Japanese Orthopedic Association (cJOA) score and visual analog scale (VAS) scores for upper extremity numbness, and radiographic parameters, including C2-C7 lordotic angle, atlanto-dens interval (ADI), and ⊿ADI, were evaluated preoperatively, at 2 years postoperatively, and at the final follow-up. RESULTS: Five patients had mucopolysaccharidoses (type I: n = 1, II: n = 3, VII: n = 1) and one patient had mucolipidoses type III. The mean age of patients at surgery was 27.5 years, and the mean postoperative follow-up period was 61 months. All mucopolysaccharidoses cases required C1 posterior arch resection with C2-C7 laminoplasty. No critical complications were observed postoperatively. There were no significant differences in C2-C7 angle (p = 0.724) and ⊿ADI (p = 0.592) between the preoperative and final follow-ups. The cJOA score and VAS for numbness significantly improved at the final follow-up (p = 0.004 and p = 0.007, respectively). CONCLUSIONS: The cervical myelopathy in patients with LSD could be safely and effectively treated with laminoplasty with/without C1 posterior arch resection after excluding patients with atlantoaxial instability. Atlantoaxial stability and symptom improvement could be maintained at an average of 5 years postoperatively.

Compound heterozygous mutations in the neuraminidase 1 gene in type 1 sialidosis: A case report and review of literature.

BACKGROUND: Type 1 sialidosis, also known as cherry-red spot-myoclonus syndrome, is a rare autosomal recessive lysosomal storage disorder presenting in the second decade of life. The most common symptoms are myoclonus, ataxia and seizure. It is rarely encountered in the Chinese mainland. CASE SUMMARY: A 22-year-old male presented with complaints of progressive myoclonus, ataxia and slurred speech, without visual symptoms; the presenting symptoms began at the age of 15-year-old. Whole exome sequencing revealed two pathogenic heterozygous missense variants [c.239C>T (p.P80L) and c.544A>G (p.S182G) in the neuraminidase 1 (NEU1) gene], both of which have been identified previously in Asian patients with type 1 sialidosis. All three patients identified in Mainland China come from three unrelated families, but all three show the NEU1 mutations p.S182G and p.P80L pathogenic variants. Increasing sialidase activity through chaperones is a promising therapeutic target in sialidosis. CONCLUSION: Through retrospective analysis and summarizing the clinical and genetic characteristics of type 1 sialidosis, we hope to raise awareness of lysosomal storage disorders among clinicians and minimize the delay in diagnosis.

[Clinical and genetic analysis of mucolipidosis in 3 pedigrees and literature review].

Objective: To investigate the clinical and genetic characteristics of 3 patients with mucolipidosis and to perform literature review. Methods: A retrospective analysis was made on the clinical data and genetic test results of 3 pedigrees with mucolipidosis. The patients were followed up at the Genetic and Prenatal Diagnosis Center of the First Affiliated Hospital of Zhengzhou University from February 2016 to August 2018. A neonatal inherited metabolic diseases gene panel including GNPTAB, GNPTG, MCOLN1, etc. was used for next-generation sequencing (NGS) based testing. Sanger sequencing was subsequently used to confirm the suspected pathological variants in the patients and their family members. Original papers on mucolipidosis published up to December 2018 were retrieved from PubMed, CNKI and WanFang databases by using the key words "mucolipidosis" AND "Chinese" . Results: The onset ages ranged from (9-90) days. The common clinical characteristics of the 3 patients are developmental delay and skeletal abnormalities. Targeted NGS revealed 5 different variations all in GNPTAB including p.Arg364Ter, p.Ser385Leu, p.Try404Ter, p. Arg587Ter, c.1284+1G>T. Two variants p.Ser385Leu and c.1284+1G>T were novel. Twenty-six cases of mucolipidosis have been reported in Chinese from 8 papers, which included 11 type ML Ⅱα/ß, 11 type ML Ⅲ α/ß and 4 type ML Ⅲ γ. c.2715+1G>A and p.Arg364Ter variants are likely the hot variants in Chinese ML patients. Conclusions: Mucolipidosis is a rare autosomal recessive disorder characterized by developmental delay and skeletal abnormalities. NGS plus Sanger sequencing detection is effective and accurate for making genetic diagnosis. p.Ser385Leu and c.1284+1G>T of GNPTAB gene are identified as novel pathogenic variants. GNPTAB gene is the main disease causing gene among Chinese ML patients, and c.2715+1G>A and p.Arg364Ter are the most common variants.

A novel spot mutation leading to sialidosis type 1-myoclonus syndrome and optical coherence tomography findings / Uma nova mutação pontual levando à sialidose tipo 1 - síndrome mioclônica e seus achados na tomografia de coerência óptica

ABSTRACT This report presents the optical coherence tomography findings and a new NEU1 mutation in bilateral macular cherry-red spot syndrome associated with sialidosis type 1. A 19-year-old patient with a macular cherry-red spot underwent metabolic and genetic analyses supported by spectral-domain optical coherence tomography. Fundus examination revealed bilateral macular cherry-red spot. Spectral-domain optical coherence tomography revealed increased hyperreflectivity in the retinal inner layers and the photoreceptor layer in the foveal region. The genetic analysis detected a new NEU1 mutation, which caused type I sialidosis. In cases with a macular cherry-red spot, sialidosis should be included in the differential diagnosis, and NEU1 mutation should be screened. Spectral-domain optical coherence tomography alone is not sufficient in the differential diagnosis because childhood metabolic diseases may exhibit similar signs.

RESUMO Neste artigo, objetivamos apresentar os achados da tomografia de coerência óptica em uma nova mutação detectada no gene NEU1 em um caso de síndrome macular vermelho-cereja bilateral associada à sialidose tipo 1. Um paciente de 19 anos com um achado de mancha macular vermelho-cereja foi submetido a análises metabólicas e genéticas, apoiadas por imagens de tomografia de coerência óptica de domínio espectral (SD-OCT). Ao exame de fundo de olho, foi observada uma mancha macular vermelho-cereja bilateral. Nas imagens de SD-OCT, observou-se hiper-refletividade nas camadas internas da retina e na camada fotorreceptora na região foveal. Foi realizada uma análise genética e uma nova mutação foi detectada no gene NEU1, resultando em sialidose tipo 1. Nos casos em que é detectada uma mancha vermelho-cereja na mácula, o diagnóstico diferencial de sialidose deve ser feito e mutações do gene NEU1 devem ser rastreadas. A SD-OCT por si só não é suficiente para o diagnóstico diferencial, porque achados de aparência semelhante podem se manifestar em casos de doenças metabólicas da infância.

A case of nephrosialidosis caused by mutation of neuraminidase 1 gene / 中华肾脏病杂志

The child was a 9-year-old girl, and sought medical advice due to "proteinuria for over a month". Renal biopsy result showed focal segmental glomerulosclerosis with diffuse vacuolization of glomerular podocytes and tubular epithelial cells. The child was diagnosed as type Ⅱ sialidosis with a compound heterozygote mutation in neuraminidase 1 gene for c.239C>T(p.Pro80Leu), c.220G>C(p.Val74Leu) and c.205A>G(p.Arg69Gly). Her father was proved to carry the first mutation, and her mother carried the other two, respectively. The report aims to improve the clinician's understanding of the rare disease. Early diagnosis can help avoid overuse of immunosuppressants, guide treatment reasonably and improve prognosis.

Type Ⅰ sialidosis:four case reports / 中国神经精神疾病杂志

Sialidosis is a rare autosomal recessive disorder which is classified into type Ⅰ and Ⅱ according to the age of onset and severity of the disease.Type I,also known as mucolipidosis,is often manifested as myoclonus,ataxia,general tonic clonic seizure,and bilateral cherry-red spots in eye examination.Four cases of type Ⅰ sialidosis were reported in order to improve the diagnosis and treatment of this disease.Patients were mainly manifested as myoclonus and ataxia.Whole exon gene sequencing of the four patients all showed the mutation c.544A＞G in the NEU1 gene.Meanwhile,the new mutation c.596G＞A carried was found in case 2 and its pathogenicity was also analyzed.Finally,we summarized the clinical characteristics of type Ⅰ patients in China,noting that most patients develop all the core symptoms as the disease progresses.

Microvillus inclusion disease: a case report and literature review / 中华围产医学杂志

Objective:To investigate the clinical features and genetic mutations of microvillus inclusion disease (MVID).Methods:Clinical features and gene sequencing results of a neonate with MVID in Children's Hospital of Chongqing Medical University in August 2019 were retrospectively analyzed. Literature was retrieved up to October 2021, with the terms of microvillus inclusion disease, congenital microvilli atrophy, MVID, MYO5B, STX3, and STXBP2 in China National Knowledge Infrastructure, Wanfang Database, VIP database, and PubMed. Clinical features, diagnosis, and treatment of the reported MVID cases were reviewed. Results:(1) Case report: A male infant presented with jaundice two days after birth and was admitted to our hospital. Clinical features included intractable diarrhea, intermittent abdominal distension, uncorrectable dehydration, and weight loss. Laboratory test results indicated metabolic acidosis, electrolyte disorder, and cholestasis. Whole exome sequencing confirmed the diagnosis of MVID in this baby boy with compound heterozygous mutations of c.1021C>T(p.Q341*) and c.1125G>A(p.W375*) in the MYO5B gene, which were inherited from the father and the mother, respectively. (2) Literature review: Except for the present case, 31 patients from 20 articles were reviewed, and the typical clinical manifestations were intractable diarrhea, accompanied by dehydration, metabolic acidosis, electrolyte disorder, etc. Some patients also developed extra-gastrointestinal symptoms, including feeding difficulties and malnutrition (8/18), respiratory distress syndrome (4/18) and jaundice/cholestasis (4/18) in patients with MYO5B mutations; feeding difficulties and malnutrition (2/5), respiratory distress syndrome (1/5), and sepsis (1/5) in patients with STX3 mutations; feeding difficulties (2/9), respiratory distress syndrome (1/9), jaundice/cholestasis (1/9), sepsis (1/9), and hypoglycemia (1/9) in patients with STXBP2 mutations. In terms of the demographic data and prenatal examination, preterm birth (8/18), fetal bowel dilatation (5/18), polyhydramnios (5/18), parental consanguinity (2/18), and meconium-stained amniotic fluid (2/18) occurred among patients with MYO5B mutations. In those with STX3 mutations, parental consanguinity (3/5), fetal bowel dilatation (1/5), polyhydramnios (1/5), and meconium-stained amniotic fluid (1/5) occurred. Of nine patients with STXBP2 mutations, parental consanguinity (3/9), preterm birth (2/9), and polyhydramnios (2/9) occurred. Conclusions:MVID has atypical clinical features and a high mortality, resulting in difficulty in the diagnosis and treatment. The possibility of MVID should be considered when an infant presents with intractable diarrhea, dehydration, metabolic acidosis, and electrolyte disorder accompanied by multiple extra-gastrointestinal symptoms. Early identification of MYO5B, STX3, and STXBP2 mutations will benefit prompt intervention, prognosis evaluation, and genetic counseling.

Clinical and genetic analysis of mucolipidosis in 3 pedigrees and literature review / 中华儿科杂志

Objective@#To investigate the clinical and genetic characteristics of 3 patients with mucolipidosis and to perform literature review.@*Methods@#A retrospective analysis was made on the clinical data and genetic test results of 3 pedigrees with mucolipidosis. The patients were followed up at the Genetic and Prenatal Diagnosis Center of the First Affiliated Hospital of Zhengzhou University from February 2016 to August 2018. A neonatal inherited metabolic diseases gene panel including GNPTAB, GNPTG, MCOLN1, etc. was used for next-generation sequencing (NGS) based testing. Sanger sequencing was subsequently used to confirm the suspected pathological variants in the patients and their family members. Original papers on mucolipidosis published up to December 2018 were retrieved from PubMed, CNKI and WanFang databases by using the key words "mucolipidosis" AND "Chinese" .@*Results@#The onset ages ranged from (9-90) days. The common clinical characteristics of the 3 patients are developmental delay and skeletal abnormalities. Targeted NGS revealed 5 different variations all in GNPTAB including p.Arg364Ter, p.Ser385Leu, p.Try404Ter, p. Arg587Ter, c.1284+1G>T. Two variants p.Ser385Leu and c.1284+1G>T were novel. Twenty-six cases of mucolipidosis have been reported in Chinese from 8 papers, which included 11 type ML Ⅱα/β, 11 type ML Ⅲ α/β and 4 type ML Ⅲ γ. c.2715+1G>A and p.Arg364Ter variants are likely the hot variants in Chinese ML patients.@*Conclusions@#Mucolipidosis is a rare autosomal recessive disorder characterized by developmental delay and skeletal abnormalities. NGS plus Sanger sequencing detection is effective and accurate for making genetic diagnosis. p.Ser385Leu and c.1284+1G>T of GNPTAB gene are identified as novel pathogenic variants. GNPTAB gene is the main disease causing gene among Chinese ML patients, and c.2715+1G>A and p.Arg364Ter are the most common variants.

Síndrome de Kinsbourne manifestando-se com quadro de encefalite pós-viral / Kinsbourne syndrome manifesting with signs of post-viral encephalitis

OBJETIVO: Descrever um caso de síndrome de Kinsbourne manifestando-se com quadro de encefalite pós-viral e rever a da literatura. DESCRIÇÃO DO CASO: Criança do sexo feminino, dois anos e seis meses, encaminhada de outro serviço com história de ataxia, irritabilidade e dificuldades articulatórias na fala após episódio prodrômico de febre, lesões de pele e mucosa. Com hipótese de encefalite pós-viral, a avaliação clínica evidenciou quadro de síndrome opsoclônus-mioclonia-ataxia ou síndrome de Kinsbourne. Foi afastada a associação de neuroðblastoma oculto e iniciada terapêutica com corticosteroide. Durante internação e acompanhamento ambulatorial, houve regressão progressiva e normalização do quadro clínico e neurológico inicial. COMENTÁRIOS: Apesar de se tratar de uma doença rara, o diagnóstico de síndrome de Kinsbourne deve ser reconhecido pelos pediatras e intensivistas, com objetivo de instituir traðtamento específico precoce, embora com resultados variáveis, sendo fundamental a exclusão de neuroblastoma oculto.

OBJECTIVE: To describe a case of Kinsbourne syndrome manifesting with signs of post-viral encephalitis, and to review the literature. CASE DESCRIPTION: Female child, aged two years and six months. She was referred from another hospital with a history of ataxia, irritability, and dysphasia after a prodromal episode of fever, skin and mucosa lesions. Referred with suspected post-viral encephalitis, the child was diagnosed with the opsoclonus-myoclonus-ataxia syndrome (Kinsbourne syndrome). The association of occult neuroblastoma was dismissed and therapy with corticosteroids was initiated. During hospitalization and outpatient treatment, there was a progressive regression and normalization of the clinical and neurological original condition. COMMENTS: Albeit a rare disease, the diagnosis of Kinsðbourne syndrome should be recognized by pediatricians and intensivists in order to start an early specific treatment, being important to exclude occult neuroblastomas. The results of the treatment are variable.

"Cherry red spot" in a patient with Tay-Sachs disease: case report / "Mácula em cereja" em paciente com doença de Tay-Sachs: relato de caso

Tay-Sachs disease is an autosomal recessive disorder of sphingolipid metabolism, caused by enzime hexosaminidase A deficiency that leads to an accumulation of GM2 in neurocytes which results in progressive loss of neurological function. The accumulation of lipid in retinal ganglion cells that leads to a chalk-white appearance of the fundus called "cherry red spot" is the hallmark of Tay-Sachs disease. It is also seen in others neurometabolic diseases as well as in central retinal artery occlusion. This case reports a child with Tay-Sachs disease in a family with four previous similar deaths without diagnostic.

Tay-Sachs é uma doença autossômica recessiva, caracterizada pela deficiência da enzima hexosaminidase A levando ao acúmulo de esfingolipídios (GM2) em células neuronais que resulta em uma perda progressiva da função neurológica. O acúmulo de lipídios em células ganglionais da retina leva a uma aparência de mácula em cereja, característica do fundo de olho de pessoas acometidas. "Mácula em cereja" também pode ser vista em outras doenças neurometabólicas e em oclusão da artéria central da retina. Este trabalho relata o caso de um paciente com doença de Tay-Sachs em uma família com história de quatro óbitos por causas semelhantes sem diagnóstico.

Mucolipidosis tipo IV en una paciente con ancestros mapuches: caso clínico / Mucolipidoses type IV in a patient with Mapuche ancestry

We report a 7 year-old girl with mapuche ancestors, diagnosed as a cerebral palsy since infancy and on active rehabilitation. She acquired motor and cognitive skills at 3 years of age. At 5 years of age, a slow neurological deterioration started, associated to visual impairment. Optic atrophy was added to the typical neurological exam ofataxic cerebral palsy and the diagnosis was re-considered. Neuroimaging showed a slow and progressive atrophy of intracerebral structures and ultramicroscopy revealed intracytoplasmatic inclusions in conjunctiva and skin, compatible with mucolipidoses type IV (ML-IV). ML-IV must be included in the differencial diagnosis of cerebral palsy associated with loss of acquired skills and progressive visual impairment. Electrón microscopy of skin or conjunctiva is a useful diagnostic test. Suspicion of ML-IV must not be restricted to Ashkenazi Jewish population.

Lysosomal storage disorders / 北京大学学报(医学版)

Lysosomal storage disorders (LSDs) are genetic defects caused by lysosomal hydrolase deficiencies. These deficiencies lead to substrate accumulation affecting cells, tissues and organs. Detecting abnormal compound excretion and deficient enzymes assist diagnosis of these disorders for treatment and prevention. This mini review summarizes clinical presentations and diagnostic workup of LSDs and updates the new development in the area.

Biochemical Characteristics of a Korean Patient with Mucolipidosis III (Pseudo-Hurler Polydystrophy)

We performed a biochemical study on the patient with mucolipidosis III (ML-III, pseudo-Hurler polydystrophy) in Korea. Confluent fibroblasts from the patient and from normal controls were cultured for 4, 12, 24, 48, and 72 hr, respectively. Lysosomal enzyme activities in culture media after different incubation times and in plasma, leukocytes, and fibroblasts were determined. Most of the leukocyte lysosomal enzymes were within normal limits or slightly lowered; however, plasma lysosomal enzyme activities such as those of hexosaminidase and arylsulfatase A were markedly increased. Numerous phase-dense inclusions were present in the cytoplasm of cultured fibroblasts. Lysosomal enzyme activities of fibroblasts were markedly decreased except for beta-glucosidase. The rates of increase of the lysosomal enzyme activities with incubation time were greater in the culture medium of the patient than in normal control, whereas no difference in the beta-glucosidase activity of the culture media of the patient and the control was found. This study describes the first case of ML-III in Korea, with its typical biochemical characteristics, i.e., a problem with targeting and transporting of lysosomal enzymes which results in a marked increase in plasma lysosomal enzyme activities and a high ratio of extracellular to intracellular lysosomal enzyme activities in cultured fibroblasts.