First Three Years' Experience of Mucopolysaccharidosis Type-I Newborn Screening in California.

OBJECTIVE: To report on the first 3 years of mucopolysaccharidosis type I (MPS I) newborn screening (NBS) in the large and diverse state of California. STUDY DESIGN: The California Genetic Disease Screening Program began universal NBS for MPS I on August 29, 2018. The screening uses a 2-tiered approach: an α-L-iduronidase (IDUA) enzyme activity assay followed by DNA sequencing for variants in the IDUA gene. RESULTS: As of August 29, 2021, 1 295 515 California newborns were screened for MPS I. In tier 1 of screening, 329 (0.025%) had an IDUA enzyme measurement below the cutoff and underwent tier-2 IDUA DNA sequencing. After tier 2, 146 (0.011%) newborns were screen positive, all of whom were referred to a metabolic Special Care Center for follow-up. After long-term follow-up, 7 cases were resolved as severe MPS I (Hurler syndrome) and 2 cases as attenuated MPS I for an MPS I birth prevalence of 1/143 946. DNA sequencing identified 107 unique IDUA variants among a total of 524 variants; 65% were known pseudodeficiency alleles, 25% were variants of uncertain significance, and 10% were pathogenic variants. CONCLUSIONS: As a result of a 2-tiered NBS approach, 7 newborns diagnosed with Hurler syndrome had received early treatment for MPS I. Continuation of California's long-term follow-up program will be crucial for further understanding the complex genotype-phenotype relationships of MPS I.

Hurler Syndrome: a Biochemically Confirmed Case in Dominican Republic

Abstract Mucopolysaccharidosis (MPS) is a group of metabolic disorders caused by the deficiency or complete absence of certain lysosomal enzymes responsible for the breakdown of mucopolysaccharides, causing an accumulation of glycosaminoglycans (GAGs) throughout the body. Mucopolysaccharidosis type I (MPS I), also called Hurler syndrome, is an autosomal recessive lysosomal storage disorder resulting from a deficiency of the enzyme α-L-iduronidase. This report aims to present the clinical findings and diagnosis of a 21-month-old female with no history of similar cases in their previous generations. The diagnosis was considered based on the clinical and radiological characteristics of Hurler syndrome (HS) and confirmed biochemically, becoming the first confirmed case in the Dominican Republic.

Experience of the NPC Brazil Network with a Comprehensive Program for the Screening and Diagnosis of Niemann-Pick Disease Type C.

Niemann-Pick disease type C (NPC) is a lysosomal disorder caused by impaired cholesterol metabolism. Levels of lysosphingomyelin 509 (LysoSM509) have been shown elevated in dried blood spots (DBS) of NPC and acid sphingomyelinase deficiency patients. In this study, we report our experience using a two-tier approach (1st tier is the quantification of lysoSM509 by ultra-performance liquid chromatography tandem mass spectrometry followed by the 2nd tier with next-generation sequencing of the NPC1 and NPC2 genes). DBS samples from 450 suspected patients were received by the NPC Brazil network. Of these, 33 samples had elevated levels of lysoSM509, and in 25 of them, variants classified as pathogenic, likely pathogenic, or of unknown significance were identified in the NPC1 or NPC2 genes by next-generation sequencing. The quantification of lysoSM509 in DBS as a first-tier test for the diagnosis of NPC followed by molecular analysis of the NPC1 and NPC2 genes almost doubled the detection rate when compared to the performance of chitotriosidase activity as a first-tier biomarker, and it could likely be increased with the addition of a third tier with MLPA of the two genes involved. This strategy seems suitable for the neonatal screening (NBS) of NPC if this disease is eventually adopted by NBS programs.

c-Abl Activation Linked to Autophagy-Lysosomal Dysfunction Contributes to Neurological Impairment in Niemann-Pick Type A Disease.

Niemann-Pick type A (NPA) disease is a fatal lysosomal neurodegenerative disorder caused by the deficiency in acid sphingomyelinase (ASM) activity. NPA patients present severe and progressive neurodegeneration starting at an early age. Currently, there is no effective treatment for this disease and NPA patients die between 2 and 3 years of age. NPA is characterized by an accumulation of sphingomyelin in lysosomes and dysfunction in the autophagy-lysosomal pathway. Recent studies show that c-Abl tyrosine kinase activity downregulates autophagy and the lysosomal pathway. Interestingly, this kinase is also activated in other lysosomal neurodegenerative disorders. Here, we describe that c-Abl activation contributes to the mechanisms of neuronal damage and death in NPA disease. Our data demonstrate that: 1) c-Abl is activated in-vitro as well as in-vivo NPA models; 2) imatinib, a clinical c-Abl inhibitor, reduces autophagy-lysosomal pathway alterations, restores autophagy flux, and lowers sphingomyelin accumulation in NPA patient fibroblasts and NPA neuronal models and 3) chronic treatment with nilotinib and neurotinib, two c-Abl inhibitors with differences in blood-brain barrier penetrance and target binding mode, show further benefits. While nilotinib treatment reduces neuronal death in the cerebellum and improves locomotor functions, neurotinib decreases glial activation, neuronal disorganization, and loss in hippocampus and cortex, as well as the cognitive decline of NPA mice. Our results support the participation of c-Abl signaling in NPA neurodegeneration and autophagy-lysosomal alterations, supporting the potential use of c-Abl inhibitors for the clinical treatment of NPA patients.

Coexistencia infrecuente de la enfermedad de Tay-Sachs, coartación aórtica y reflujo vesicoureteral de grado V / Rare coexistence of Tay-Sachs disease, coarctation of the aorta and grade V vesicoureteral reflux

La enfermedad de Tay-Sachs es una enfermedad metabólica hereditaria neurodegenerativa. Existen cuatro tipos según el inicio de los síntomas clínicos: infantil, infantil de inicio tardío, juvenil y adulto. El tipo infantil tiene el peor pronóstico. Recientemente, se describieron diferentes anomalías que acompañan a los trastornos metabólicos e influyen en el pronóstico. Presentamos el caso de un lactante con enfermedad de Tay-Sachs junto con coartación aórtica y reflujo vesicoureteral bilateral (RVU) de grado V. Se realizó el seguimiento del paciente en el consultorio externo de Cardiología Pediátrica. En la ecografía abdominal, se observó ectasia pielocalicial, y se detectó reflujo vesicoureteral bilateral de grado V en la cistouretrografía miccional. No se ha informado previamente la coexistencia de estas anomalías. Este caso pone de manifiesto que no se deben subestimar las anomalías del examen neurológico en los pacientes con una cirugía cardíaca reciente, porque podría perderse la oportunidad de diagnosticar enzimopatías congénitas.

Tay-Sachs disease is a neurodegenerative inherited metabolic disease. There are four forms classified by the time of first clinical symptoms: infantile, late infantile, juvenile and adult. Infantile form has the poorest prognosis. Lately, different abnormalities which accompany metabolic disorders and affect the prognosis have been described. We present an infant with Tay-Sachs disease accompanied by coarctation of the aorta and bilateral grade V vesicoureteral reflux (VUR). The patient was followed up in the outpatient clinic of Pediatric Cardiology. The abdominal ultrasonography showed pelvicalyceal ectasia; bilateral grade V VUR in voiding cystourethrography was found. This coexistence has not been previously reported. This case emphasizes that abnormalities in the neurological examination of cardiac postsurgical patients should not be underestimated because the opportunity to diagnose inborn errors of metabolism could be missed.

Rare coexistence of Tay-Sachs disease, coarctation of the aorta and grade V vesicoureteral reflux. / Coexistencia infrecuente de la enfermedad de Tay-Sachs, coartación aórtica y reflujo vesicoureteral de grado V.

Tay-Sachs disease is a neurodegenerative inherited metabolic disease. There are four forms classified by the time of first clinical symptoms: infantile, late infantile, juvenile and adult. Infantile , Ebru Candab, Ertürk Leventc , The infantile form has the poorest clinical prognosis. First symptoms of this form, such as muscle weakness and hypotonia, occur around form has the poorest prognosis. Lately, different abnormalities which accompany metabolic disorders and affect the prognosis have been described. We present an infant with Tay-Sachs disease accompanied by coarctation of the aorta and bilateral grade V vesicoureteral reflux (VUR). The patient was followed up in the outpatient clinic of Pediatric Cardiology. The abdominal ultrasonography showed pelvicalyceal ectasia; bilateral grade V VUR in voiding cystourethrography was found. This coexistence has not been previously reported. This case emphasizes that abnormalities in the neurological examination of cardiac postsurgical patients should not be underestimated because the opportunity to diagnose inborn errors of metabolism could be missed.

La enfermedad de Tay-Sachs es una enfermedad metabólica hereditaria neurodegenerativa. Existen cuatro tipos según el inicio de los síntomas clínicos: infantil, infantil de inicio tardío, juvenil y adulto. El tipo infantil tiene el peor pronóstico. Recientemente, se describieron diferentes anomalías que acompañan a los trastornos metabólicos e influyen en el pronóstico. Presentamos el caso de un lactante con enfermedad de Tay-Sachs junto con coartación aórtica y reflujo vesicoureteral bilateral (RVU) de grado V. Se realizó el seguimiento del paciente en el consultorio externo de Cardiología Pediátrica. En la ecografía abdominal, se observó ectasia pielocalicial, y se detectó reflujo vesicoureteral bilateral de grado V en la cistouretrografía miccional. No se ha informado previamente la coexistencia de estas anomalías. Este caso pone de manifiesto que no se deben subestimar las anomalías del examen neurológico en los pacientes con una cirugía cardíaca reciente, porque podría perderse la oportunidad de diagnosticar enzimopatías congénitas.

Proteomic Analysis of Niemann-Pick Type C Hepatocytes Reveals Potential Therapeutic Targets for Liver Damage.

Niemann-Pick type C disease (NPCD) is a lysosomal storage disorder caused by mutations in the NPC1 gene. The most affected tissues are the central nervous system and liver, and while significant efforts have been made to understand its neurological component, the pathophysiology of the liver damage remains unclear. In this study, hepatocytes derived from wild type and Npc1-/- mice were analyzed by mass spectrometry (MS)-based proteomics in conjunction with bioinformatic analysis. We identified 3832 proteins: 416 proteins had a p-value smaller than 0.05, of which 37% (n = 155) were considered differentially expressed proteins (DEPs), 149 of them were considered upregulated, and 6 were considered downregulated. We focused the analysis on pathways related to NPC pathogenic mechanisms, finding that the most significant changes in expression levels occur in proteins that function in the pathways of liver damage, lipid metabolism, and inflammation. Moreover, in the group of DEPs, 30% (n = 47) were identified as lysosomal proteins and 7% (n = 10) were identified as mitochondrial proteins. Importantly, we found that lysosomal DEPs, including CTSB/D/Z, LIPA, DPP7 and GLMP, and mitocondrial DEPs, AKR1B10, and VAT1 had been connected with liver fibrosis, damage, and steatosis in previous studies, validiting our dataset. Our study found potential therapeutic targets for the treatment of liver damage in NPCD.

Mucopolysaccharidosis VII in Brazil: natural history and clinical findings.

BACKGROUND: Mucopolysaccharidosis type VII (MPS VII), also known as Sly syndrome, caused by deficiency of the lysosomal enzyme ß-glucuronidase, is an ultra-rare disorder with scarce epidemiological data and few publications about natural history and clinical spectrum. METHODS: We conducted a case series report which included retrospective data from all MPS VII patients diagnosed through the "MPS Brazil Network" who were known to be alive in 2020 in Brazil (N = 13). Clinical data were obtained from a review of the medical records and descriptive statistics and variables were summarized using counts and percentages of the total population. RESULTS: The majority of the patients were from the Northeast region of Brazil. Among the signs and symptoms that raised the clinical suspicion of MPS, coarse face was the most frequent; 58% of the patients had a history of non-immune hydrops fetalis. All the subjects presented short neck and trunk. The majority presented typical phenotypical signs of MPS disorders. They all presented neurodevelopmental delay and cognitive impairment. About half of this cohort had knees deformities. Dysostosis multiplex was identified in almost all patients and cardiomyopathy was less frequent than observed in other types of MPSs. The mean age at diagnosis was 5 years, ranging from 1 to 14 years. Almost all patients (12/13) were homozygous for the c.526C>T (p.Leu176Phe) mutation. A novel variant of the GUSB gene was found, the c.875T>C (p.Leu292Pro), in a compound heterozygous with the c.526C>T (p.Leu176Phe) variant. CONCLUSIONS: This case series is the biggest data collection of MPS VII patients alive in Latin America. The overall clinical picture of the MPS VII patients is very similar to other MPS disorders, including a spectrum of severity and delayed diagnosis.

Long-term impact of early initiation of enzyme replacement therapy in 34 MPS VI patients: A resurvey study.

Patients with mucopolysaccharidosis type VI (MPS VI) present with a wide range of disease severity and clinical manifestations, with significant functional impairment and shortened lifespan. Enzyme replacement therapy (ERT) with galsulfase has been shown to improve clinical and biochemical parameters including patient survival, quality of life and growth. The present study is a resurvey of 34 Brazilian MPS VI patients with rapidly progressive disease (classical phenotype) who initiated ERT with galsulfase under five years of age and had been on ERT until data collection in 2019, with few exceptions (n = 4 patients who died before 2019). Anthropometric measures, urinary glycosaminoglycans, and data regarding cardiac, orthopedic, neurologic, sleep apnea, hearing and ophthalmologic outcomes were filled in by specialists. Pubertal development, clinical complications, hospitalizations, and surgeries were also assessed. In this resurvey study, treatment with galsulfase has shown to be safe and well tolerated in MPS VI patients who initiated ERT under the age of 5 years and who have been undergoing ERT for approximately 10 years. Mortality rate suggests that early initiation of ERT may have a positive impact on patients' survival, improving but not preventing disease progression and death. MPS VI patients on ERT also showed improved growth velocity and the pubertal development was normal in all surviving patients. Follow-up data on pneumonia and hospitalization suggest that early ERT may have a protective effect against major respiratory complications. Cardiac valve disease progressed since their prior evaluation and spinal cord compression was observed in a large number of patients, suggesting that these disease complications were not modified by ERT.

Clinical Manifestation in Females with X-linked Metabolic Disorders: Genetic and Pathophysiological Considerations

Abstract Inborn errors of metabolism are predominantly autosomal-recessive disorders, but several follow an X-linked pattern of inheritance. They are called X-linked recessive, if the female carriers are asymptomatic, and are called X-linked dominant disorders, if almost all females are affected. Conditions, in which some females have symptoms while others are asymptomatic lifelong are simply referred to as X-linked. The aim of this review is to point out the variability in clinical manifestation of affected females in some X-linked metabolic disorders and to discuss on the basis of these examples possible mechanisms that may explain the broad phenotypic spectrum, such as the type of the underlying mutation, the issue of autonomous versus non-autonomous gene expression and the degree of skewing of X-inactivation. The use of the terms "X-linked dominant" and "X-linked recessive" will be discussed.

Clinical and molecular characteristics of colombian patients with mucopolysaccharidosis IVA, and description of a new galns gene mutation.

A study published in 2012 estimated incidence of MPS IVA, in 0.68 cases per 100, 000 live births in Colombia, and according to the Colombian Fund for High-Cost Diseases, in 2014 there were 15 people diagnosed with MPS IV. To enhance the knowledge of the disease in the country, we aimed to characterize clinical and molecular findings in 12 MPS IVA patients. Twelve patients were included in the study, with most patients of female gender (n = 7, 58,3%), age range 2 to 28 years, average weight 26 kg (17.6-43 kg), average height 97 cm (92-104 cm), average BMI 27.6 kg/m2 (19.92-47.65 kg/m2). Clinical findings were similar to those described in the literature. GALNS gene molecular analysis showed five homozygous missense mutations in exon 11 c.1156C > T or p.R386C, a single nonsense mutation in the heterozygous state c.974G > A p.W325, and heterozygous in exon 9 mutation of exon 3 c.280C > T p.R94C, missense variant reported by Ogawa in 1995 [17]. There was only one patient that presented a homozygous missense mutation in exon 9 c.901G > T p.G301C and four patients showed the heterozygous form. A heterozygous missense mutation in exon 5 c.425A > T p.H142L, which has not been previously reported, was found in a female patient, 2 years 11 months of age. The diagnosis algorithms that include molecular analysis, bioinformatic predictive tools, pharmacogenomics, and proteomics helps to improve the diagnosis, treatment, and prognosis of patients affected by MPS IVA.

Enfermedad de Gaucher, diagnostico en el embarazo, reporte de caso y consideraciones de su tratamiento en Colombia / Gaucher disease, diagnosis in pregnancy, report case study and considerations of its treatment in Colombia

RESUMEN Introducción y Objetivo: La enfermedad de Gaucher es una condición autosómica recesiva de baja prevalencia, de difícil diagnóstico y manejo, especialmente en embarazo. Reportamos una gestante con enfermedad de Gaucher manejada desde la semana 15,3 hasta el término del embarazo con Taliglucerasa en la Unidad de Alta Complejidad Obstétrica, en la Fundación Valle del Lili en Cali, Colombia. Métodos: Reporte de caso de gestante con diagnóstico de enfermedad de Gaucher diagnosticada durante el embarazo, con exacerbación de síntomas, quien presento severa pancitopenia y esplenomegalia. Resultados: El manejo medico interdiscilplinario permitió el control del severo deterioro clínico de la paciente durante el parto, presentó hemorragia postparto con choque hipovolémico, con adecuada respuesta al manejo médico. La madre y el neonato fueron dados de alta sin otras complicaciones asociadas. Conclusión: El manejo interdisciplinario es indispensable en gestantes con esta entidad para lograr buenos resultados maternos y perinatales.

ABSTRACT Introduction and Objective: Gaucher disease is a low prevalence autosomal recessive condition, difficult to diagnose and manage especially during pregnancy. We reported a pregnant woman with Gaucher disease managed with Taliglucerase in a critical care obstetric unit from week 15.3 until the end of her pregnancy, at the Fundación Valle del Lili, Cali, Colombia. Methods: A case report of a pregnant woman diagnosed during her pregnancy with Gaucher disease, who presented severe pancytopenia and splenomegaly. Results: The interdisciplinary medical management allowed the control of the severe clinical deterioration of the patient. During the delivery, she presented postpartum hemorrhage with hypovolemic shock, which resolved with medical management. The mother and the newborn were discharged without other associated complications. Conclusion: Interdisciplinary management is essential for handling a critically ill obstetric patient with Gaucher disease, and to achieve good maternal and perinatal outcomes.

Determination of genotypic and clinical characteristics of Colombian patients with mucopolysaccharidosis IVA.

BACKGROUND: As mucopolysaccharidosis IVA (MPS IVA) is the most frequent MPS in Colombia, this paper aims to describe its clinical and mutational characteristics in 32 diagnosed patients included in this study. METHODS: Genotyping was completed by amplification and Sanger sequencing of the GALNS gene. The SWISS-model platform was used for bioinformatic analysis, and mutant proteins were generated by homology from the wild-type GALNS code 4FDI template from the Protein Data Bank (PDB) database. Docking was performed using the GalNAc6S ligand (PubChem CID: 193456) by AutoDock Vina 1.0 and visualized in PyMOL and LigPlot+. RESULTS: Eleven variants were identified, and one new pathogenic variant was described in the heterozygous state, which is consistent with genotype c. 319 G> T or p.Ala107Ser. The pathogenic variant c.901G>T or p.Gly301Cys was the most frequent mutation with 51.6% of alleles. Docking revealed affinity energy of -5.9 Kcal/mol between wild-type GALNS and the G6S ligand. Some changes were evidenced at the intermolecular interaction level, and affinity energy for each mutant decreased. CONCLUSION: Clinical variables and genotypic analysis were similar to those reported for other world populations. Genotypic data showed greater allelic heterogeneity than those previously reported. Bioinformatics tools showed differences in the binding interactions of mutant proteins with the G6S ligand, in regard the wild-type GALNS.

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.

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

Galactosialidosis (OMIM #256540) is an autosomal recessive lysosomal storage disorder caused by mutations in the CTSA gene, which encodes the protective protein cathepsin A. The loss of function of this protein causes a secondarily deficiency of beta-galactosidase and N-acetyl-a-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.

La galactosialidosis (OMIM #256540) es una enfermedad metabólica lisosomal causada por mutaciones en el gen CTSA, que codifica la proteina 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.

GNPTAB missense mutations cause loss of GlcNAc-1-phosphotransferase activity in mucolipidosis type II through distinct mechanisms.

Mucolipidoses (ML) II and III alpha/beta are lysosomal storage diseases caused by pathogenic mutations in GNPTAB encoding the α/ß-subunit precursor of GlcNAc-1-phosphotransferase. To determine genotype-phenotype correlation and functional analysis of mutant GlcNAc-1-phosphotransferase, 13 Brazilian patients clinically and biochemical diagnosed for MLII or III alpha/beta were studied. By sequencing of genomic GNPTAB of the MLII and MLIII alpha/beta patients we identified six novel mutations: p.D76G, p.S385L, p.Q278Kfs*3, p.H588Qfs*27, p.N642Lfs*10 and p.Y1111*. Expression analysis by western blotting and immunofluorescence microscopy revealed that the mutant α/ß-subunit precursor p.D76G is retained in the endoplasmic reticulum whereas the mutant p.S385L is correctly transported to the cis-Golgi apparatus and proteolytically processed. Both mutations lead to complete loss of GlcNAc-1-phosphotransferase activity, consistent with the severe clinical MLII phenotype of the patients. Our study expands the genotypic spectrum of MLII and provides novel insights into structural requirements to ensure GlcNAc-1-phosphotransferase activity.

Ultrastructural deposits appearing as "zebra bodies" in renal biopsy: Fabry disease?- comparative case reports.

BACKGROUND: Fabry Disease (FD) is a genetic disorder caused by alpha-galactosidase A deficiency. Certain drugs, such as hydroxychloroquine, can produce renal deposits that mimic morphological findings seen in FD, characterizing a type of drug-induced renal phospholipidosis. CASE PRESENTATION: Case 1: A 28-year-old female patient with systemic lupus erythematosus who had been using hydroxychloroquine for 14 months presented subnephrotic proteinuria. Renal biopsy showed deposits compatible with FD. Neither activity analysis of alpha-galactosidase A nor genetic analysis were available and were not performed. These deposits were not detected in a subsequent renal biopsy three years after withdrawal of the medication, characterizing a possible hydroxychloroquine-induced renal phospholipidosis. Case 2: A 29-year-old male patient presented with acroparesthesia, angiokeratomas, cornea verticillata and subnephrotic proteinuria. Deposits compatible with FD were detected upon renal biopsy. The evaluation of alpha-galactosidase A showed no activity in both blood and leukocytes. Genetic analysis identified an M284 T mutation in exon 6, and such mutation was also found in other family members. CONCLUSION: Clinical investigation is necessary in suspected cases of Fabry Disease upon renal biopsy in order to confirm diagnosis. Drug-induced renal phospholipidosis should be considered in differential diagnosis in cases with intracellular osmiophilic, lamellar inclusions in electron microscopy.

Newborn screening for six lysosomal storage disorders in a cohort of Mexican patients: Three-year findings from a screening program in a closed Mexican health system.

OBJECTIVE: To evaluate the results of a lysosomal newborn screening (NBS) program in a cohort of 20,018 Mexican patients over the course of 3years in a closed Mexican Health System (Petróleos Mexicanos [PEMEX] Health Services). STUDY DESIGN: Using dried blood spots (DBS), we performed a multiplex tandem mass spectrometry enzymatic assay for six lysosomal storage disorders (LSDs) including Pompe disease, Fabry disease, Gaucher disease, mucopolysaccharidosis type I (MPS-I), Niemann-Pick type A/B, and Krabbe disease. Screen-positive cases were confirmed using leukocyte enzymatic activity and DNA molecular analysis. RESULTS: From July 2012 to April 2016, 20,018 patients were screened; 20 patients were confirmed to have an LSD phenotype (99.9 in 100,000 newborns). Final distributions include 11 Pompe disease, five Fabry disease, two MPS-I, and two Niemann-Pick type A/B patients. We did not find any Gaucher or Krabbe patients. A final frequency of 1 in 1001 LSD newborn phenotypes was established. DISCUSSION: NBS is a major public health achievement that has decreased the morbidity and mortality of inborn errors of metabolism. The introduction of NBS for LSD presents new challenges. This is the first multiplex Latin-American study of six LSDs detected through NBS.

Progressive heart disease in mucopolysaccharidosis type I mice may be mediated by increased cathepsin B activity.

Mucopolysaccharidosis type I (MPS I) is a lysosomal disorder characterized by a deficiency of alpha-L-iduronidase and storage of undegraded glycosaminoglycans (GAGs). Clinical findings of the disease include heart failure, and patients often need valve replacement. It has been shown that, later in life, MPS I mice develop those abnormalities, but to date, there have not been studies on the progression and pathogenesis of the disease. Therefore, in the present study, we evaluated heart function in normal and MPS I male mice from 2 to 8 months of age. Echocardiographic analysis showed left ventricular enlargement with progressive reduction in ejection fraction, fractional area change, and left ventricular fractional shortening in the MPS I hearts at 6 and 8 months of age and a reduction in acceleration time/ejection time ratio of the pulmonary artery starting at 6 months of age, which suggests pulmonary vascular resistance. Histological and biochemical analysis confirmed progressive GAG storage from 2 months of age and onwards in the myocardium and heart valves, which had also increased in thickness. Additionally, macrophages were present in the MPS I heart tissue. Collagen content was reduced in the MPS I mouse valves. Cathepsin B, an enzyme that is known to be able to degrade collagen and is involved in heart dilatation, displayed a marked elevation in activity in the MPS I mice and could be responsible for the heart dilatation and valves alterations observed. Our results suggest that the MPS I mice have progressive heart failure and valve disease, which may be caused by cathepsin B overexpression.

Altered dynamics of a lipid raft associated protein in a kidney model of Fabry disease.

Accumulation of globotriaosylceramide (Gb3) and other neutral glycosphingolipids with galactosyl residues is the hallmark of Fabry disease, a lysosomal storage disorder caused by deficiency of the enzyme alpha-galactosidase A (α-gal A). These lipids are incorporated into the plasma membrane and intracellular membranes, with a preference for lipid rafts. Disruption of raft mediated cell processes is implicated in the pathogenesis of several human diseases, but little is known about the effects of the accumulation of glycosphingolipids on raft dynamics in the context of Fabry disease. Using siRNA technology, we have generated a polarized renal epithelial cell model of Fabry disease in Madin-Darby canine kidney cells. These cells present increased levels of Gb3 and enlarged lysosomes, and progressively accumulate zebra bodies. The polarized delivery of both raft-associated and raft-independent proteins was unaffected by α-gal A knockdown, suggesting that accumulation of Gb3 does not disrupt biosynthetic trafficking pathways. To assess the effect of α-gal A silencing on lipid raft dynamics, we employed number and brightness (N&B) analysis to measure the oligomeric status and mobility of the model glycosylphosphatidylinositol (GPI)-anchored protein GFP-GPI. We observed a significant increase in the oligomeric size of antibody-induced clusters of GFP-GPI at the plasma membrane of α-gal A silenced cells compared with control cells. Our results suggest that the interaction of GFP-GPI with lipid rafts may be altered in the presence of accumulated Gb3. The implications of our results with respect to the pathogenesis of Fabry disease are discussed.