Leucodistrofia metacromática del adulto: reporte de caso / Adult-onset metachromatic leukodystrophy

RESUMEN INTRODUCCIÓN: La leucodistrofia metacromática (LDM) es una enfermedad poco frecuente que se caracteriza por desmielinización progresiva a nivel del sistema nervioso central y periférico. En la mayoría de los casos, es causada por una actividad deficiente de la enzima arilsulfatasa-A. Pertenece al grupo de las leucodistrofias, que son trastornos hereditarios de la sustancia blanca asociados con una variabilidad fenotípica y una heterogeneidad genética importante. El fenotipo de la LDM suele relacionarse con la edad de presentación, que puede variar desde la infancia hasta la adultez. Cuando se presenta en la edad adulta, puede debutar con manifestaciones neuropsiquiátricas, lo que lleva con frecuencia a diagnósticos erróneos. REPORTE DE CASO: Se presenta el caso de una paciente adulta que debutó con un cuadro clínico caracterizado por cambios comportamentales progresivos, con posterior inicio de manifestaciones clínicas motoras. El diagnóstico de LDM se sospechó a partir de la clínica y los hallazgos típicos en la resonancia magnética (RM) cerebral, y se confirmó con la detección de actividad deficiente de la arilsulfatasa-A (ARSA) y la secuenciación del gen ARSA que confirmó la mutación en estado homocigoto, compatible con este diagnóstico. DISCUSIÓN: Destacamos en este caso la importancia de la sospecha clínica, el reconocimiento temprano y el manejo multidisciplinario como factores pronósticos del curso de la enfermedad, ya que en la actualidad no hay tratamiento definitivo para la enfermedad.

ABSTRACT INTRODUCTION: Metachromatic leukodystrophy (MLD) is an infrequent disease characterized by progressive demyelination of the central and peripheral nervous system. In most cases, it is caused by deficient activity of arylsulfatase-A. It belongs to the group of leukodystrophies, which are inherited white matter disorders that can be associated with significant phenotypic variability and genetic heterogeneity. The phenotype in MLD is usually related to the age of onset, which can vary from childhood to adulthood. Adult-onset MLD can debut with neuropsychiatry symptoms, which can often lead to misdiagnosis. CASE REPORT: We report the case of an adult female patient who presented with progressive behavioral changes, followed by motor manifestations. MLD was initially suspected based on the clinical presentation and the characteristic findings on brain magnetic resonance imaging (MRI), with subsequent confirmation by detection of deficient arylsulfatase-A (ARSA) activity and ARSA gene sequencing, which demonstrated homozygosity, compatible with this diagnosis. DISCUSSION: We highlight the importance of clinical suspicion, early recognition and multidisciplinary management as a prognostic factor for the course of the disease, since there is currently no definitive treatment for the disease.

Analysis of ARSA gene variant in an infant with late infantile metachromatic leukodystrophy / 中华医学遗传学杂志

OBJECTIVE@#To detect pathogenic variant of ARSA gene in an infant with late infantile metachromatic leukodystrophy (MLD).@*METHODS@#The male proband had an onset of walking dysfunction and seizure at 28 months. Arylsulfatase A activity of his peripheral blood leucocytes was 26.9 nmol/mg.17h, and cranial MRI showed wild symmetrical demyelination. With genomic DNA extracted from his peripheral blood sample, all coding exons and splicing sites of the ARSA gene were subjected to Sanger sequencing. PubMed Protein BLAST system was employed to analyze cross-species conservation of the mutant amino acid. Ucsf chimera software was used to analyze the impact of candidate variants on the secondary structure of the protein product. Impact of potential variants was also analyzed with software including PolyPhen-2, Mutation Taster, SIFT and PROVEAN. Whole-exome sequencing was carried out to identify additional variants which may explain the patient's condition.@*RESULTS@#The proband was found to harbor compound heterozygous variants of the ARSA gene [c.467G>A (p.Gly156Asp) and c.960G>A (p.Trp320*)], neither of which was reported previously. As predicted by Ucsf chimera software, the c.960G>A (p.Trp320*) variant may demolish important secondary structures including α-helix, β-strand and coil of the ARSA protein, causing serious damage to its structure and loss of function. The c.467G>A (p.Gly156Asp) variant was predicted to be "probably damaging" by PolyPhen-2, Mutation Taster and SIFT software.@*CONCLUSION@#The patient's condition may be attributed to the compound heterozygous c.467G>A (p.Gly156Asp) and c.960G>A (p.Trp320*) variants of the ARSA gene. Above results have facilitated genetic counseling and prenatal diagnosis for this family.

Leucodistrofia metacromática infantil tardía: Presentación de un caso / Late infantile metachromatic leukodystrophy: case report

La leucodistrofia metacromática es una enfermedad autosómi-ca recesiva poco común ocasionada por el déficit de la enzima lisosomal arilsulfatasa A, el cual provoca una desmielinización progresiva con manifestaciones neurológicas subsecuentes. Dentro de sus formas de manifestación, la infantil tardía es la de peor pronóstico. La resonancia magnética juega un papel importante en la caracterización de anormalidades subyacentes, lo que permite descartar otras afecciones clínicas y aproximar un diagnóstico, que, posteriormente, es confirmado mediante los análisis moleculares apropiados. Dado el escaso conocimiento de esta enfermedad, sumado a un curso clínico generalmente fatal, se hace fundamental una identificación temprana y precisa con el fin de iniciar un manejo paliativo y asesoría genética. Se presenta a una paciente femenina de 24 meses de edad con historia de retardo psicomotor y hallazgos imagenológicos compatibles con leucodistrofia. Los estudios enzimáticos y moleculares confirmaron el diagnóstico de leu-codistrofia metacromática infantil tardía.

Metachromatic leukodystrophy is an uncommon autosomal recessive disease caused by the deficiency of the arylsulfatase A lysosomal enzyme, which causes a progressive demyelin-ation with subsequent neurological manifestations. Between its manifestation forms, the one presenting in late childhood has the worst prognosis. Magnetic resonance plays an important role in the characterization of underlying abnormalities, which makes it possible to rule out other clinical conditions and approximate a diagnosis that is later confirmed by the appropriate molecular studies. Given the limited knowledge of the condition, coupled with a generally fatal clinical course, an early and accurate identification is fundamental in order to start palliative management and genetic counseling. A 24 months old female patient with psychomotor retardation history and imaging findings compatible with leukodystrophy is presented. Enzymatic and molecular studies confirmed a diagnosis of late childhood metachromatic leukodystrophy.

Metachromatic leukodystrophy. Case presentation / Leucodistrofia metacromática. Presentación de caso

ABSTRACT Metachromatic leukodystrophy (MLD) is a rare demyelinating disease (prevalence 1:40,000), also called arylsulfatase A deficiency (ARS-A), which may present with neurological and psychiatric symptoms. Clinical assessment may be difficult, due to unspecific signs and symptoms. A case is presented of a 16 year-old female patient seen in psychiatry due to behavioural changes, psychosis, and with impaired overall performance. She was ini tially diagnosed with schizophrenia, but the Nuclear Magnetic Resonance (NMR) scan and laboratory tests lead to the diagnosis of MLD.

RESUMEN La leucodistofia metacromática (LDM) es una enfermedad desmielinizante rara (prevalencia, 1:40.000), también llamada deficiencia de arilsulfatasa A (ARS-A), que puede presentarse con síntomas neurológicos y psiquiátricos y cuyo diagnóstico puede plantear dificultades para el clínico, dado lo inespecífico de los signos y síntomas. Se presenta el caso de una paciente de 16 arios atendida por psiquiatría por cambios conductuales, psicosis y deterioro general del funcionamiento. Inicialmente diagnosticada como esquizofrenia, se documentaron por resonancia magnética y pruebas de laboratorio en la evolución cambios que llevaron al diagnóstico de leucodistrofia metacromática.

A Korean Patient with Early Juvenile Form of Metachromatic Leukodystrophy: Biochemical and Molecular Genetic Investigation

Metachromatic leukodystrophy is an inherited lysosomal storage disorder caused by the deficiency of arylsulfatase A activity. The patient in this study, a 5-yr-old girl, presented with progressive psychomotor regression. An MRI image of her brain showed bilateral symmetrical demyelination. The arylsulfatase A activity in her leukocytes was decreased to 8.0 nmol/hr/mg protein (reference range, 25-80 nmol/hr/mg protein). Mutation analysis of ARSA, using PCR and direct sequencing, showed two heterozygote pathogenic variations of c.449C>T (p.Pro150Leu) and c.640G>A (p.Ala214Thr). In summary, we report a Korean patient with an early juvenile form of metachromatic leukodystrophy, who was diagnosed based on her clinical symptoms as well as by using biochemical, radiological, and molecular genetic investigations.

Biochemical and Genetic Analysis of Seven Korean Individuals With Suspected Metachromatic Leukodystrophy

Metachromatic leukodystrophy (MLD) is an autosomal recessive disease caused by a deficiency in arylsulfatase A (ARSA). However, decreased ARSA activity is also observed in pseudodeficiency (PD). To distinguish between MLD and PD, we performed gene mutation and sulfatide analyses by using dried blood spots (DBSs) from seven Korean individuals who underwent an analysis of ARSA activity. DNA was extracted from DBSs, and PCR-direct sequencing of ARSA was performed. The cDNA obtained was analyzed to confirm a novel mutation. Of the seven subjects, three were confirmed as having MLD, one was confirmed as having MLD-PD, one was confirmed as having PD, and the remaining two were obligate heterozygotes. We verified the novel pathogenic variant c.1107+1delG by performing familial and cDNA analyses. Sulfatide concentrations in DBSs were analyzed and were quantified by using ultra-performance liquid chromatography and tandem mass spectrometry, respectively. Total sulfatide concentration was inversely correlated with ARSA activity (Spearman's coefficient of rank correlation, P=0.929, P=0.0025). The results of this mutational and biochemical study on MLD will increase our understanding of the genetic characteristics of MLD in Koreans.

Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry Measurement of Leukocyte Arylsulfatase A Activity Using a Natural Substrate

No abstract available.

Analysis of phenotype and genotype in a family with late infantile metachromatic leukodystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study genotype-phenotype correlation of a family with late infantile metachromatic leukodystrophy(MLD).</p><p><b>METHODS</b>Clinical data were collected and ARSA gene was tested by PCR and sequencing in a pedigree.</p><p><b>RESULTS</b>The male proband onset with walking dysfunction at 19 months, arylsulfatase A activity of leucocyte from his peripheral blood was 20.2 nmol/mg.17h, and his cranial MRI showed wildly symmetrical demyelination. Homozygosis for novel c.622delC (p.His208Metfs46X) in exon 3 of ARSA gene was identified in proband, and heterozygous for the same mutation in parents and grandma of the proband.</p><p><b>CONCLUSION</b>Late infantile metachromatic leukodystrophy is characterized by rapid and progressive regression of neuropsychiatric and motor development. There is a significant correlation between the mutation of c.622delC(p.His208Metfs*46) in the ARSA gene and the phenotype presenting as O/O patients.</p>

Can endometrial arylsulfatase A activity predict the onset of endometrial polyps over the years? / A atividade da arilsulfatase endometrial A pode prever a aparição de pólipos endometriais ao longo dos anos?

PURPOSE: To assess if arylsulfatase A activity (ASA) and sulfatide (SL) concentration in the human endometrium can be predictive of the development of endometrial polyps over the years, since ASA activity reflects the endometrial sensitivity to hormones. METHODS: ASA activity and SL concentration were determined by biochemical procedures on endometrial samples collected between 1990 and 1994 in non-menopausal women. These women underwent a new endometrial sampling following the clinical indication some years after the first endometrial sampling. The histological assessment of the second endometrial specimens found four patients with normal endometrial pattern and 10 patients with one or more endometrial polyps. ASA activity/years elapsed and SL concentration/years elapsed were compared using two tailed Mann-Whitney test for unpaired data between patients with normal pattern and patients with endometrial polyps. RESULTS: Median ASA activities were 2.62 (normal pattern) versus 1.85 (endometrial polyps) nmol hydrolized substrate/min. Median activity/years elapsed is higher in patients with second endometrial sample presenting normal pattern (p=0.006) and median SL concentration/years elapsed does not differ significantly among groups, even if median SL concentration seems to be higher in patients who subsequently developed polyps (1031 µg/g of fresh tissue versus 341,5 µg/g of fresh tissue). CONCLUSIONS: ASA activity can predict the onset of endometrial polyps over the years.

OBJETIVO: Avaliar se a atividade da arilsulfatase A (ASA) e a concentração de sulfatida (SL) no endométrio humano pode ser preditivo em relação ao desenvolvimento de pólipos endometriais ao longo dos anos, posto que atividade da ASA reflete a sensibilidade do endométrio aos hormônios. MÉTODOS: A atividade da ASA, assim como a concentração de SL, foi determinada por meio de procedimentos bioquímicos em amostras de endométrio coletadas entre 1990 e 1994, em mulheres que não se encontravam na menopausa. Essas mulheres foram submetidas a uma nova amostragem endometrial após indicação clínica alguns anos depois da primeira amostragem endometrial. A avaliação histológica dos segundos espécimes endometriais permitiu identificar quatro pacientes com padrão endometrial normal e 10 com um ou mais pólipos endometriais. A atividade da ASA/anos depois e a concentração de SL/anos depois foram comparadas, utilizando o teste bilateral U de Mann-Whitney para dados não pareados entre as pacientes com padrão normal e as pacientes com pólipos endometriais. RESULTADOS: A ativitade da ASA foi 2,62 (padrão normal) em comparação com 1,85 (endometrial pólipos) de substrato hidrolisado/min. A atividade da ASA/anos depois é maior em pacientes com segunda amostra endometrial a apresentarem um padrão normal (p=0,006), e a concentração mediana de SL/anos depois não difere de forma significativa entre os grupos, apesar de a concentração mediana de SL parecer maior em pacientes que posteriormente desenvolveram pólipos (1031 µg/g de tecido fresco em comparação com 341,5 µg/g de tecido fresco). CONCLUSÕES: A atividade da ASA pode prever a aparição de pólipos endometriais ao longo dos anos.

A Case of Metachromatic Leukodystrophy Confirmed by Molecular Genetic Analysis

Metachromatic leukodystrophy (MLD) is the rare neurometabolic disease caused by the deficiency of the enzyme arylsulfatase A resulting in a deficiency of sulfatide degradation and the target gene is ARSA gene. We report a case of the late infantile form of MLD that was confirmed by means of enzyme assay and gene analysis with typical brain MRI and MR spectroscopy finding.

Estudio de las enzimas lisosomales N-acetil-a-D-glucosaminidasa y arilsulfatasa A en adultos cubanos / Assay of lysosomal N-acetyl-a-D-glucosaminidase and arylsulfatase A activities in Cuban adults

El objetivo de este estudio fue determinar, en una muestra de individuos cubanos, un rango preliminar de valores normales de actividad específica de N-acetil- a-D-glucosaminidasa y arilsulfatasa A, enzimas deficientes en la mucopolisacaridosis tipo III B y la leucodistrofia metacromática, respectivamente. Se realizó una investigación de corte transversal, en muestras de sangre de 38 individuos adultos. Se realizó la extracción de los leucocitos y se determinó la actividad específica de las enzimas por métodos espectrofotométricos. Todos los participantes fueron caracterizados desde el punto de vista clínico como sanos para ambas enfermedades. Se obtuvieron valores medios de actividad específica de N-acetil-a-D-glucosaminidasa y arilsulfatasa A de 1,52±0,30 y 121,37±20,14 nmol/mg/h, respectivamente. No se encontraron diferencias significativas en relación a las características étnicas para ninguna de las dos enzimas (p<0,05). Este constituye el primer estudio cubano en el cual se publican rangos de actividad específica para estas enzimas en individuos cuya condición de sanos y no relacionados familiarmente con la enfermedad ha sido clínicamente demostrada. El análisis de un mayor número de muestras permitirá establecer los puntos de corte que dotarán al diagnóstico bioquímico de estas enfermedades de una mayor confiabilidad.

The aim of this study was to determine, in a sample of Cuban individuals, a preliminary range of normal values of N-acetyl-a-D-glucosaminidase and arylsulfatase A activity, enzymes that are deficient in mucopolysaccharidosis type III B and metachromatic leukodystrophy, respectively. A cross-sectional research was conducted. Blood samples were obtained out of 38 adult individuals. The leucocytes were extracted and the specific enzymatic activity was assayed by spectrophotometric methods. All participants were characterized from the clinical point of view as healthy for both diseases. Average values of N-acetyl-a-D-glucosaminidase and arylsulfatase A specific activities of 1.52 ± 0.30 and 121.37 ± 20.14 nmol/mg/h, respectively were obtained. There were no significant differences related to ethnicity for any of the two enzymes (p <0.05). This is the first Cuban study in which ranges of activity for these enzymes have been reported in healthy individuals whose healthy and non-familiarly related with the disease status have been clinically demonstrated. The analysis of more samples will establish the cutoff points that will increase the reliability of the biochemical diagnosis of these diseases.

A Case of 22q13 Deletion Syndrome

The deletion 22q13 syndrome (Phelan-McDermid syndrome) is a rare microdeletion syndrome characterized by prominent neurobehavioral deficits including neonatal hypotonia, developmental delay, language delay, autism, and minor dysmorphic features. Due to nonspecific facial features and difficulties in detection in routine chromosome analysis, this chromosome deletion syndrome has gone under-diagnosed. Fluorescence in situ hybridization (FISH) is required to confirm the presence of this deletion. Here we report the first case of 22q13 deletion syndrome in Korea. An 18-month-old girl was admitted to a pediatric clinic due to severe developmental delay and hypotonia from the neonatal period. She was diagnosed as 22q13 deletion syndrome through a chromosomal analysis and FISH using arylsulfatase A probe.

Identification of a Novel Splicing Mutation in the ARSA Gene in a Patient with Late-infantile Form of Metachromatic Leukodystrophy / 대한진단검사의학회지

Metachromatic leukodystrophy (MLD; MIM 250100), a severe neurodegenerative disorder inherited as an autosomal recessive trait, is caused by mutations in the arylsulfatase A (ARSA) gene. Although several germ line ARSA mutations have been identified in patients with MLD of various ethnic backgrounds elsewhere in the world, no genetically confirmed cases of MLD have been reported in Korea. Recently, we identified a mutation in the ARSA gene of a Korean male with MLD. A male infant with late-infantile form of MLD had been admitted to our hospital for further examination. His neuromuscular symptoms, which included inability to walk at the age of 12 months, gradually worsened, even after allograft bone marrow transplantation; he died at the age of 9 yr. His elder brother had also been diagnosed with MLD. To confirm the presence of a genetic abnormality, all the coding exons of the ARSA gene and the flanking introns were amplified by PCR. A molecular analysis of the ARSA gene revealed both a novel heterozygous splicing mutation (c.1101+1G>T) in intron 6 and a heterozygous missense mutation in exon 2 (c.296G>A; Gly99Asp). The patient's elder brother who had MLD is believed to have had the same mutation, which may be correlated with a rapidly deteriorating clinical course. This study identified a novel mutation in the ARSA gene, related to a late-infantile form of MLD with a lethal clinical course and suggested that molecular diagnosis of patients may be useful in early diagnosis and for deciding intervention measures for their family members.

Characterization of arylsulphatase A in a 70 kDa protein isolated from goat spermatozoa having Na+, K+-ATPase inhibitory activity.

A protein having inhibitory effect on Na+, K+-ATPase as well as showing arylsulphatase A activity (ASA) was isolated from the cytosolic fraction of goat spermatozoa and characterized biochemically. The molecular mass of the protein was found to be 70 kDa (P70) on 10% SDS-PAGE after 35% ammonium sulphate precipitation, followed by hydroxyapatite column chromatographic separation. The isoelectric point (pI) of the protein was found to be 4.9. The sequencing results of first ten N-terminal amino acid residues of protein showed 100%, 90%, and 80% homology with N-terminal 18-27 amino acid residues of mice, pig and human testicular ASA, respectively. The optimum pH, temperature and incubation time for maximum ASA activity of the protein was 5.5, 37°C and 30 min respectively. The ASA activity of protein and AS from a commercial source was studied with respect to the sensitivity to different metal ions, vanadate, carbonyl compounds and ascorbate. Inhibition of AS activity of P70 by silver nitrate suggested that it was related to ASA. Comparable effects of different polyunsaturated fatty acids (eicosapentaenoic and docosahexaenoic acids) and purified anti P70-antibody on P70 and AS from commercial source were observed. The findings suggested that protein was novel in nature, having both regulatory and catalytic functions and showed similarities with the ASA reported from different sources.

Contaminación por monóxido de carbono: un problema de salud ambiental / Carbon monoxide contamination: an environmental health problem

El monóxido de carbono es considerado uno de los mayores contaminantes de la atmósfera terrestre. Sus principales fuentes productoras responsables de aproximadamente 80 por ciento de las emisiones, son los vehículos automotores que utilizan como combustible gasolina o diesel y los procesos industriales que utilizan compuestos del carbono. Esta sustancia es bien conocida por su toxicidad para el ser humano. Sus efectos tóxicos agudos incluida la muerte han sido estudiados ampliamente; sin embargo, sus potenciales efectos adversos a largo plazo son poco conocidos. En los últimos años, los estudios de investigación experimentales en animales y epidemiológicos en humanos han evidenciado relación entre población expuesta en forma crónica a niveles medios y bajos de monóxido de carbono en aire respirable y la aparición de efectos adversos en la salud humana especialmente en órganos de alto consumo de oxígeno como cerebro y corazón. Se han documentado efectos nocivos cardiovasculares y neuropsicológicos en presencia de concentraciones de monóxido de carbono en aire inferiores a 25 partes por millón y a niveles de carboxihemoglobina en sangre inferiores a 10 por ciento. Las alteraciones cardiovasculares que se han descrito son hipertensión arterial, aparición de arritmias y signos electrocardiográficos de isquemia. Déficit en memoria, atención, concentración y alteraciones del movimiento tipo parkinsonismo, son los cambios neuropsicológicos con mayor frecuencia asociados a exposición crónica a bajos niveles de monóxido de carbono y carboxihemoglobina.

Carbon monoxide is considered to be a major factor contaminating earths atmosphere. The main sources producing this contamination are cars using gasoline or diesel fuel and industrial processes using carbon compounds; these two are responsible for 80 percent of carbon monoxide being emitted to the atmosphere. This substance has a well-known toxic effect on human beings and its acute poisonous effects (including death) have been widely studied; however, its long-term chronic effects are still not known. During the last few years, experimental research on animals and studies of human epidemiology have established the relationship between chronic exposure to low and middle levels of carbon monoxide in breathable air and adverse effects on human health, especially on organs consuming large amounts of oxygen such as the heart and brain. Harmful cardiovascular and neuropsychological effects have been documented in carbon monoxide concentration in air of less than 25 ppm and in carboxyhaemoglobin levels in blood of less than 10 percent. The main cardiac damage described to date has been high blood pressure, cardiac arrhythm and electrocardiograph signs of ischemia. Lack of memory, attention, concentration and Parkinson-type altered movement are the neuropsychological changes most frequently associated with chronic exposure to low levels of carbon monoxide and carboxyhaemoglobin.

A Case of Adult-onset Metachromatic Leukodystrophy with Normal Nerve Conduction Studies

Adult-onset metachromatic leukodystrophy (MLD) is very rare with a combination of cognitive and behavioral symptoms and peripheral polyneuropathy. A 47-year-old man was admitted due to memory impairment, gait disturbance, dysarthria and personality changes for a period of 3 years. The arylsulfatase A level in his leukocytes was decreased. A brain MRI showed bilateral symmetrical demyelination but nerve conduction velocities (NCV) were normal. We report a very rare case of adult-onset MLD with normal NCV.

Analysis of ARSA mutations in a Chinese family with metachromatic leukodystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify arylsulftase A gene (ARSA) mutations in a Chinese family with MLD.</p><p><b>METHODS</b>There were two MLD patients in the investigated family. The proband, an 11-year-old girl, was well until the age of 5 years, when she began to experience difficult walking and mental regression. Magnetic resonance imaging (MRI) of her brain showed widespread demyelination, nerve conduction velocity reduced, and ASA activity measured in white blood cells was zero. So, the child was diagnosed having MLD. The proband's young brother also got the same phenotype except clinical symptom being milder than hers. Their parents and elder sister all had normal phenotypes. Genomic DNA samples were extracted from peripheral bloods of the proband and all her family members. All 8 exons and exon-intron boundaries of ARSA gene were amplified by polymerase chain reaction (PCR) and followed by direct DNA sequencing.</p><p><b>RESULTS</b>Two heterozygous mutations of ARSA, which were named as, G251A (R84Q) and G296T (G99V) were identified in the proband. The two mutations were located in exon 2. The same genotype was found in the proband's young brother, but these mutations were not detected in proband's elder sister. The proband's mother had the heterozygous mutations G296T (G99V), and her father had the heterozygous mutation G251A (R84Q).</p><p><b>CONCLUSION</b>These two MLD patients are with both compound heterozygous mutations, which mean one allele with the G296T (G99V) mutation was from their mother, and the other allele with the G251A (R84Q) mutation got from their father. The parents are both carrier with normal phenotype.</p>

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.

Effect of collection, transport, processing and storage of blood specimens on the activity of lysosomal enzymes in plasma and leukocytes

This study was designed to evaluate the effect of different conditions of collection, transport and storage on the quality of blood samples from normal individuals in terms of the activity of the enzymes Beta-glucuronidase, total hexosaminidase, hexosaminidase A, arylsulfatase A and Beta-galactosidase. The enzyme activities were not affected by the different materials used for collection (plastic syringes or vacuum glass tubes). In the evaluation of different heparin concentrations (10 percent heparin, 5 percent heparin, and heparinized syringe) in the syringes, it was observed that higher doses resulted in an increase of at least 1-fold in the activities of Beta-galactosidase, total hexosaminidase and hexosaminidase A in leukocytes, and Beta-glucuronidase in plasma. When the effects of time and means of transportation were studied, samples that had been kept at room temperature showed higher deterioration with time (72 and 96 h) before processing, and in this case it was impossible to isolate leukocytes from most samples. Comparison of heparin and acid citrate-dextrose (ACD) as anticoagulants revealed that Beta-glucuronidase and hexosaminidase activities in plasma reached levels near the lower normal limits when ACD was used. In conclusion, we observed that heparin should be used as the preferable anticoagulant when measuring these lysosomal enzyme activities, and we recommend that, when transport time is more than 24 h, samples should be shipped by air in a styrofoam box containing wet ice

Hepatic arylsulfatases A and B activities in streptozocin - induced diabetic rats

Reduction of sulfated glycosaminoglycans [GAG] in the liver and kidney of streptozocin-induced diabetic rats has been attributed to lowered synthesis and perhaps higher degradation of such compounds in these organs. To measure hepatic lysosomal arylsulfatases A and B, [the enzymes responsible for the removal of sulfate groups from GAG], in starved and streptozocin-induced diabetic rats. Diabetes was induced by streptozocin injection [40 mg per kg body weight] through the caudal vein in rats. After two weeks, the livers were removed and homogenized. Activities of arylsulfatases A and B were measured and compared with those of the liver homogenates from healthy and starved rats. The activity of liver arylsulfatase A in starved diabetic rats increased 2.15 fold as compared with normal starved animals, while that of fed diabetic rats was 3.16 fold higher than their respective control group. Increases of 1.70 and 1.94 fold in specific activities of arylsulfatase B was noticeable in the livers of diabetic animals under fed and starved conditions, respectively. It appears that increased hydrolysis of sulfated GAG by liver lysosomal arylsulfatases A and B in streptozocin-induced diabetic rats may be among the contributing factors in the reduction of such sulfated compounds in this tissue