Galactosialidosis: nueva mutación de novo en el gen CTSA en un paciente afecto de la forma infantil tardía / Galactosialidosis: a new "de novo" mutation in CTSA gene in a patient with late infantile galactosialidosis

La galactosialidosis (OMIM #256540) es una enfermedad metabólica lisosomal causada por mutaciones en el gen CTSA, que codifica la proteína protectora catepsina A. La pérdida de función de dicha proteína causa, secundariamente, un déficit combinado de dos enzimas, beta-galactosidasa y neuraminidasa. Se expone el caso de un paciente que presentó manifestaciones clínicas compatibles con el subtipo infantil tardío de galactosialidosis. El análisis bioquímico mostró déficits de las dos enzimas implicadas, mientras que el estudio molecular reveló dos mutaciones: una nueva mutación nunca antes descrita, p.His475Pro (c.1424 A>C), y una mutación previamente reportada, p.Arg441Cys (c.1321C>T), localizadas en los exones 15 y 14, respectivamente.

Galactosialidosis (OMIM #256540) is an autosomal recessive lysosomal storage disorder caused by mutations in the CTSAgene, which encodes the protective protein cathepsin A. The loss of function of this protein causes a secondarily deficiency of beta-galactosidase and N-acetyl-α-neuraminidase enzymes activities. We describe the clinical, biochemical and molecular analysis of a case report with a phenotype compatible with the late infantile form. The biochemical analysis reveled deficiencies of beta-galactosidase and neuraminidase activities in dried blood spot and fibroblasts and the molecular study showed two missense mutations in the CTSA gene: a previously reported mutation, p.Arg441Cys (c.1321C>T), and a novel mutation, p.His475Pro (c.1424 A>C), located in exons 14 and 15, respectively.

Informe de evaluación científica basada en la evidencia disponible: examen genético molecular / Scientific evaluation report based on available evidence: molecular genetic examination

INTRODUCCIÓN: Las enfermedades de depósito lisosomal son un grupo heterogéneo de errores metabólicos poco frecuentes, congénitos, de origen genético, caracterizados por la deficiencia funcional de los lisosomas y por la acumulación intralisosomal de sustratos. Se han caracterizado cerca de 50 desórdenes metabólicos de este origen, causados por alteraciones genéticas a nivel enzimático, de receptores, proteínas activadoras, de membrana o transportadora, causando la acumulación lisosomal de sustratos, específicos para cada enfermedad. La acumulación es progresiva, causando finalmente el deterioro funcional celular y tisular. Varios de estos desórdenes afectan el sistema nervioso central, y la mayoría de los pacientes tienen disminución de la esperanza de vida y morbilidad asociada. Para efectos del presente informe de evaluación se consideraron las patologías Mucopolisacaridosis I; Mucopolisacaridosis II; Mucopolisacaridosis VI; Enfermedad de Gaucher y Enfermedad de Fabry. TECNOLOGÍAS SANITARIAS EVALUADAS: Examen genético molecular: secuenciación y/o genotipificación. EFICACIA DE LAS INTERVENCIONES: La intervención es eficaz, cumpliendo con lo dispuesto en la letra a), del artículo 2, del decreto supremo N°13, de 2017, del Ministerio de Salud, que aprueba Reglamento que Establece el Proceso destinado a determinar los Diagnósticos y Tratamientos de Alto Costo con Sistema de Protección Financiera, según lo establecido en los artículos 7° Y 8° de la ley N° 20.850. ANÁLISIS ECONÓMICO: El costo total de implementación de los exámenes es de $ 2.037.565 anuales en el año 2018 y hasta $ 6.883.384 en el 2022. CONCLUSIÓN: Para dar cumplimiento al artículo 28° del Reglamento que establece el proceso destinado a determinar los diagnósticos y tratamientos de alto costo con Sistema de Protección Financiera, según lo establecido en los artículos 7°y 8° de la ley N°20.850, aprobado por el decreto N°13 del Ministerio de Salud, se concluye que el presente informe de evaluación se considera no favorable, de acuerdo a lo establecido en el Título III. de las Evaluaciones Favorables de la Norma Técnica N° 0192 de este mismo ministerio.

Las enfermedades de depósito lisosomal: ¿por qué los pacientes consultan al reumatólogo? / Lysosomal storage diseases: why do patients consult the rheumatologist?

The lysosomal storage diseases (LSD) are a group of approximately 50 hereditary diseases affecting the activity of several enzymes that degrade macromolecules within lysosomes. As consequence, incompletely degraded substrates are accumulated, causing cell damage and progressive multisystem diseases. Although they are considered part of the so called “rare diseases”, the LSD have become relevant since the availability for several of them of a specific treatment, through the periodic infusion of recombinant forms of the deficient enzymes. This enzyme replacement therapy can significantly improve the prognosis and the quality of life of patients. Several of the LSD affect the osteoarticular system, given symptoms that lead patients to consult first to the rheumatologist. The aim of this review is to highlight the clinical aspects of LSD, giving raise to the differential diagnosis with the rheumatic diseases...

Las enfermedades de depósito lisosomal (EDL) son un grupo de aproximadamente 50 patologías hereditarias que afectan la actividad de las enzimas que degradan diversas macromoléculas dentro de los lisosomas. Como consecuencia, se acumulan sustratos incompletamente degradados, produciendo daño celular y un cuadro clínico multisistémico y progresivo. Aunque se les considera parte de las llamadas “enfermedades raras”, las EDL han adquirido relevancia, pues desde hace pocos años es posible el tratamiento específico de varias de ellas a través de la infusión periódica de formas recombinantes de las enzimas deficientes, lo que puede mejorar significativamente el pronóstico vital y la calidad de vida de los pacientes. Dado que varias de las EDL comprometen al sistema osteoarticular, no es infrecuente que los pacientes consulten en primera instancia al reumatólogo. El objetivo de esta revisión es destacar los aspectos clínicos de aquellas EDL en las que se puede plantear el diagnóstico diferencial con patologías reumatológicas...

Diagnosing lysosomal storage diseases in a Brazilian non-newborn population by tandem mass spectrometry

OBJECTIVES: High-throughput mass spectrometry methods have been developed to screen newborns for lysosomal storage disorders, allowing the implementation of newborn screening pilot studies in North America and Europe. It is currently feasible to diagnose Pompe, Fabry, Gaucher, Krabbe, and Niemann-Pick A/B diseases, as well as mucopolysaccharidosis I, by tandem mass spectrometry in dried blood spots, which offers considerable technical advantages compared with standard methodologies. We aimed to investigate whether the mass spectrometry methodology for lysosomal storage disease screening, originally developed for newborns, can also discriminate between affected patients and controls of various ages. METHODS: A total of 205 control individuals were grouped according to age and subjected to mass spectrometry quantification of lysosomal α-glucosidase, β-glucocerebrosidase, α-galactosidase, acid sphingomyelinase, galactocerebrosidase, and α−L-iduronidase activities. Additionally, 13 affected patients were analyzed. RESULTS: The median activities for each enzyme and each age group were determined. Enzyme activities were significantly lower in individuals aged older than 18 years compared with those in newborns. Affected patients presented enzymatic activities corresponding to less than 20% of the age-matched controls. CONCLUSIONS: Our data indicate that the mass spectrometry methodology can be used for the screening of lysosomal storage diseases in non-newborn patients. However, for some diseases, such as Fabry and mucopolysaccharidosis I, a combination of biochemical and clinical data may be necessary to achieve accurate diagnoses. .

Enfermedades por depósito lisosomal: diagnóstico a partir de lesiones cutáneas / Lysosomal storage diseases, diagnosis from skin lesions

Las enfermedades por depósito lisosomal (EDL) son un grupo heterogéneo de más de 40 dolencias genéticas, debidas a la deficiencia de diversas enzimas encargadas de metabolizar sustancias dentrode los lisosomas. Estas macromoléculas se depositan dentro de las organelas de múltiples órganos y dan lugar a diversos signos y síntomas.Muchas de estas enfermedades tienen manifestaciones cutáneas, e incluso en algunas oportunidades es el dermatólogo quien sospecha el diagnóstico a partir de las lesiones en piel.En el presente trabajo se describen 8 pacientes con EDL, diagnosticados en nuestro servicio entre 2009 y 2010, en los cuales las lesiones en piel fueron la clave para arribar al diagnóstico.Cinco pacientes presentaban enfermedad de Fabry (un varón y 4 mujeres), uno mucopolisacaridosis 2 (sexo masculino), uno beta-manosidosis (sexo masculino) y el último galactosialidosis (sexo femenino).Los angioqueratomas fueron la manifestación cutánea más frecuente, y la clave diagnóstica en los pacientes con Fabry, el paciente con manosidosis y la paciente con galactosialidosis, mientras que la lesión en piel que llevó a sospechar mucopolisacaridosis 2 fueron manchas mongólicas aberrantes, algunas lenticulares, que comprometían el tronco.En cuatro pacientes el diagnóstico se confirmó por estudios enzimáticos en gota de sangre en papel de filtro, leucocitos y/u orina. En cinco pacientes (uno de los cuales ya había sido diagnosticado deforma bioquímica) se realizó estudio molecular. En todos los pacientes se hicieron los estudios complementarios necesarios para evaluar extensión del compromiso extracutáneo y necesidad de tratamientoespecífico (en aquellos pacientes en los cuales su enfermedad de base dispone de terapia de reemplazo enzimático). En uno de los pacientes con Fabry se inició terapia específica.El interés de nuestro trabajo radica en mostrar distintas EDL en las cuales el rol del dermatólogo fue fundamental para arribar al diagnóstico, resaltando..

Lysosomal-storage disorders are a group of more than 40 heterogeneous hereditary diseases dueto the deficiency of various lysosomal enzymes, in charge of the metabolization of macromolecules,with accumulation of the undigested substances inside those organelles througout severalorgans, deriving in the multiple symptoms and signs of these diseases.A great number of these diseases may have cutaneous lesions, and in many cases the dermatologistmay be the one to suggest the diagnosis.We describe eight patients with lisosomal storage diseases diagnosed at our hospital during 2009and 2010, on whom the cutaneous lesions were the clue to the diagnosis. Five patients were diagnosed as Fabry´s disease (1 male and 4 females), one as mucopolisaccharidosis2 (male), one as mannosidosis (male) and the last one as galactosyalidosis (female). Angiokeratomaswhere the most frequent cutaneous manifestation, and the key to the diagnosis inFabry’s, beta mannosidosis and galactosyalidosis, while aberrant and lenticular mongolian spotson the trunk led us to the diagnosis of mucopolissacharidosis 2.On four patients the diagnosis was confirmed by biochemical work-up. On five patients (one ofthem had already been confirmed with biochemistry) a genetic study was also performed.On all the patients studies where performed to evaluate the extension of the systemic disease andthe need of a specific treatment (for those diseases where it is available). One of the patients withFabry´s disease started the treatment soon after the diagnosis.We would like to emphasize the fundamental role of the dermatologist in diagnosing these diseases,stressing not only the academic importance of these rare diseases but also the possibility ofstarting in many of them specific enzyme replacement treatment.

Use of Tandem Mass Spectrometry for Newborn Screening of 6 Lysosomal Storage Disorders in a Korean Population / 대한진단검사의학회지

BACKGROUND: We evaluated the performance of multiplex tandem mass spectrometry (MS/MS) in newborn screening for detection of 6 lysosomal storage disorders (LSDs), namely, Niemann-Pick A/B, Krabbe, Gaucher, Fabry, and Pompe diseases and Hurler syndrome. METHODS: We revised the conditions and procedures of multiplex enzyme assay for the MS/MS analysis and determined the precision of our enzyme assay and the effects of sample amounts and incubation time on the results. We also measured the degree of correlation between the enzyme activities in the dried blood spots (DBSs) and those in the leukocytes. DBSs of 211 normal newborns and 13 newborns with various LSDs were analyzed using our revised methods. RESULTS: The intra- and inter-assay precisions were 2.9-18.7% and 8.1-18.1%, respectively. The amount of product obtained was proportional to the DBS eluate volume, but a slight flattening was observed in the product vs. sample volume curve at higher sample volumes. For each enzyme assay, the amount of product obtained increased linearly with the incubation period (range, 0-24 hr). Passing and Bablok regression analysis revealed that the enzyme activities in the DBSs and those in the leukocytes were favorably correlated. The enzyme activities measured in the DBSs were consistently lower in patients with LSDs than in normal newborns. CONCLUSIONS: The performance of our revised techniques for MS/MS detection and enzyme assays was of the generally acceptable standard. To our knowledge, this is the first report on the use of MS/MS for newborn screening of LSDs in an Asian population.

Fabry disease: A treatable lysosomal storage disorder.

Fabry disease is a lysosomal storage disease with an X-linked inheritance pattern, which presents in childhood as acroparaesthesias. Its non-specific symptoms often lead to delays in the diagnosis. We report the case of a 13-year-old boy who presented with typical acroparaesthesia of Fabry disease, his younger brother had gastrointestinal manifestations of the disease and their mother’s symptoms suggested that she is a carrier. Enzyme replacement therapy helped in ameliorating the patient’s symptoms and preventing complications such as renal failure, stroke and cardiovascular disorders.

Lysosomal storage disorders.

This study was conducted to assess the variability of clinical expression of Lysosomal storage disorders (LSDs) and the selection of specific enzyme investigation to reach the differential diagnosis. Initially 150 children in the age range of 15 days to 13 years were screened for common metabolic disorder and based on screening results, clinical signs and symptoms, 30 children(4 mo-12 yr) of these were selected for the leukocyte enzyme study. Of these 21 were confirmed to have LSDs. The most common disorder was GM2-gangliosidosis (47.61%, 10/21) followed by mucopolysaccharidosis (33.33%; 7/21). All showed variable phenotypic expression. Metachromatic leukodystrophy (MLD) was observed in 9.5% (2/21) of children with arylsulphatase A enzyme deficiency, while two children had shown pseudodeficiency of arylsulphatase A. One case each of galactosialidosis and GMI-gangliosidosis were observed. We conclude that children with developmental delay, seizures, dysmorphic features and organomegaly, with or without positive urinary screening for common metabolic disorders, need to be investigated further for LSDs.Variability of clinical expression is commonly observed in LSDs which require further confirmation by specific leukocyte enzyme study.

Pilot neonatal screening program for lysosomal storage disorders, using lamp-1.

We have demonstrated that the lysosome associated membrane protein (LAMP-1) is elevated in plasma from approximately 70% of lysosomal storage disorder patients. As part of the development of a newborn screening program for lysosomal storage disorders we have developed a first tier screening assay based upon the level of LAMP-I in blood spots taken from newborn Guthrie cards. To determine the effectiveness of the first-tier marker a prospective pilot Guthrie neonatal screening program for the identification of LSD was commenced in April 1998. Prior to commencement of the pilot program ethical approval was obtained and information leaflets regarding the neonatal screening of LSD were distributed to parents at the time of their infant's Guthrie collection. The LAMP-1 assay utilizes a chicken polyclonal and a mouse monoclonal in a sandwich time resolved fluorescent immunoassay. LAMP-1 blood-spot calibrators and quality control specimens were developed and shown to be stable and reproducible. To date 11,183 infants have been screened using LAMP-1. The population distribution is described with a median and 98th percentile of 220pg/l whole blood and 483microg/l whole blood respectively. Acceptable CV% for intra and inter assay of 8.9% and 10% respectively were obtained.

Newborn screening for lysosomal storage disorders.

Lysosomal storage disorders (LSD) represent a group of over 40 distinct genetic diseases with a total incidence of approximately 1:7,000 births. Bone marrow transplantation and enzyme replacement therapy are currently in use for the treatment of some disorders and new forms of enzyme and gene replacement therapy are actively being researched. The effectiveness of these therapies, particularly for the LSD involving the central nervous system and bone pathology, will rely heavily upon the early diagnosis and treatment of the disorder, before the onset of irreversible pathology. In the absence of a family history the only practical way to detect these disorders will be by a newborn screening program. One common feature of these disorders is an increase in the number and size of lysosomes within the cell from approximately 1% to as much as 50% of total cellular volume. Associated with this, is a corresponding increase in some lysosomal proteins. We propose that the measurement of one or more of these proteins in blood spots taken from Guthrie cards, will form the basis of a newborn screening program, for the detection of all LSD. We have identified a number of lysosomal proteins as potential markers for LSD. The level of these proteins has been determined in blood spots taken from Guthrie cards and in plasma samples from over 300 LSD affected individuals representing 25 disorders. Based on these results we have proposed a strategy for a newborn screening program involving a two tier system, utilizing time resolved fluorescence immunoquantification of the protein markers in the first tier, followed by tandem mass spectrometry for the determination of stored substrates in the second tier assays.

Liver biopsies in patients with lysosomal storage disease: experience with effective sedation.

We prospectively applied a protocol used to sedate children who required a liver biopsy. Sixty liver biopsies were performed on thirty pediatric patients to assess the effects of treatment. Sixteen patients had Type 1 Gaucher's disease of which seven had a platelet count between 50-100,000/mm3. All seven had bleeding time performed and when indicated, intravenous DDAVP (1-deamino-8-D-arginine vasopressin) was used to improve hemostasis. Fourteen patients had Niemann-Pick disease type C of which eight were significantly demented and uncooperative. Before liver biopsy, all patients were sedated with the following regimen: oral chlorpromazine (1 mg/kg) followed one hour later by intravenous meperidine (1 mg/kg) and pentobarbital (maximum dosage 6 mg/kg) administered by slow intravenous injection. Liver biopsies were obtained safely on all patients. Only 1 patient (2%) developed a potentially serious complication: an obstructed airway which was readily corrected by simple repositioning. Transient less serious complications occurred in another 7 patients (12%). There was no long term sequalae of the biopsy procedures. Our study indicates that with appropriate patient selection, this sedation protocol may be useful in pediatric patients requiring a liver biopsy.

Storage disorders presenting like mucopolysaccharidosis.

The term dysostosis multiplex is specifically applied to the group of radiological features collectively found in a number of specific metabolic disorders including the mucopolysaccharidoses, mucolipidosis, mannosidosis, fucosidosis and several other rarer conditions. We report eight cases of mannosidosis, fucosidosis and mucolipidosis with special emphasis on the differentiation from the more common mucopolysaccharidoses.