A novel spot mutation leading to sialidosis type 1-myoclonus syndrome and optical coherence tomography findings.

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.

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.

Diagnóstico clínico y genético mucolipidosis II - enfermedad células de inclusión / Diagnóstico clínico e genético da mucolipidose II - doença das células de inclusão / Clinical and genetic diagnosis of mucolipidosis II - inclusion cell disease

La Mucolipidosis tipo II es una enfermedad autosómica trastorno recesivo clínicamente caracterizado por la dismorfia facial y una hiperplasia gingival severa. Relato del caso: Se porta caso de paciente de 2 años de edad, con diagnóstico de enfermedad metabólica tipo mucolipidosis II. Al examen físico se encontraron facies tosca, marcada hiperplasia gingival sintomática generalizada en maxilar superior e inferior, encías sangrantes, cuello corto, con regular sostén cefálico, piel delgada, pectus excavatus, codos normales, manos con disminución en el agarre y piel gruesa con xerosis, dificultad para elevar los brazos por encima de la cabeza, retardo global en neurodesarrollo. Por lo cual se manejó el caso de manera multidisciplinaria, permitiendo que el paciente evolucione de manera positiva al tratamiento integral, con mejoramiento en la motricidad. Conclusiones: Los fenotipos clínicos superpuestos son un desafío de diagnóstico para el personal de la salud en Odontología, especialmente en casos de mucolipidosis (ML) y trastornos mucopolisacáridos (MPS), debido a la superposición de las características clínicas

A mucolipidose tipo II é um distúrbio autossômico recessivo caracterizado clinicamente por dismorfia facial e hiperplasia gengival grave. Relato de caso: É relatado o caso de uma paciente de 2 anos com diagnóstico de doença metabólica do tipo mucolipidose II. O exame físico revelou fácies grosseira, hiperplasia gengival sintomática generalizada acentuada na mandíbula superior e inferior, gengivas sangrantes, pescoço curto, com apoio de cabeça regular, pele fina, pectus excavatus, cotovelos normais, mãos com pega diminuída e pele grossa com xerose, dificuldade em levantar os braços acima da cabeça, atraso no desenvolvimento neurológico global. Portanto, o caso foi tratado de forma multidisciplinar, permitindo que o paciente evoluísse de forma positiva para um tratamento integral, com melhora nas habilidades motoras. Conclusões: A sobreposição de fenótipos clínicos é um desafio diagnóstico para o pessoal de saúde em Odontología, especialmente nos casos de mucolipidose (ML) e distúrbios dos mucopolissacarídeos (MPS), devido à sobreposição de características clínicas

Mucolipidosis type II is an autosomal recessive disorder clinically characterized by facial dysmorphia and severe gingival hyperplasia. Case report: The case of a 2-year-old patient with a diagnosis of metabolic disease type mucolipidosis II is reported. Physical examination revealed coarse facies, marked generalized symptomatic gingival hyperplasia in the upper and lower jaw, bleeding gums, short neck, with regular head support, thin skin, pectus excavatus, normal elbows, hands with decreased grip, and thick skin with xerosis, difficulty raising the arms above the head, global neurodevelopmental delay. Therefore, the case was handled in a multidisciplinary way, allowing the patient to evolve in a positive way to comprehensive treatment, with improvement in motor skills. Conclusions: Overlapping clinical phenotypes are a diagnostic challenge for health personnel in Dentistry, especially in cases of mucolipidosis (ML) and mucopolysaccharide disorders (MPS), due to the overlapping of clinical characteristics

Clinical and radiological findings in Brazilian patients with mucolipidosis types II/III.

OBJECTIVE: The present study aims to provide orientation for clinicians and radiologists to recognize the most prevalent findings leading to diagnosis in mucolipidosis from a description of the natural history of five Brazilian cases. MATERIALS AND METHODS: We conducted an observational and retrospective study of five patients with clinical and radiological diagnosis of mucolipidosis. Clinical evaluation consisted of information obtained from records and including physical, neurologic, and dysmorphic evaluations. Radiologic studies consisted of complete skeletal radiographs of all patients. Enzyme assessment was performed for confirmation of the diagnosis. RESULTS: The five patients were referred for genetic evaluation due to disproportionate short stature with short trunk accompanied by waddling gait. Age at referral varied from 11 months to 28 years. The most prevalent findings were joint restriction (4/5 patients), neuropsychomotor developmental delay (3/5), coarse facies (2/5), hypertrophic cardiomyopathy (2/5), and mental retardation (1/4 patients). The most common radiological findings were anterior beaking of the vertebral bodies (5/5), shallow acetabular fossae (5/5), epiphyseal dysplasia (5/5), platyspondyly (4/5), pelvic dysplasia (4/5), decreased bone mineralization (4/5), scoliosis (3/5), wide and oar-shaped ribs (3/5), generalized epiphyseal ossification delay (3/5), and hypoplasia of basilar portions of ilea (3/5). Enzyme assessment showed α-iduronidase, α-mannosidase, ß-glucuronidase, hexosaminidase A, and total hexosaminidase increased in plasma and normal glycosaminoglycans concentration. One patient was clinically classified as ML II and four patients as ML III. CONCLUSIONS: The follow-up of five patients showed the typical clinical and radiological findings allowing the diagnosis, thus improving clinical management and providing adequate genetic counseling. Clinicians and radiologists can take advantage of the information from this work, enhancing their differential diagnosis ability.

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.

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.

[Microvillous inclusion disease as a cause of severe congenital diarrhea. Case report]. / Enfermedad por inclusión microvellositaria como causa de diarrea congénita severa. Caso clínico.

Congenital diarrheas correspond to a severe and low frequency digestive disease, with a high mortality. They start a few days or months after birth, leading to intestinal insufficiency and dependence on parenteral nutrition. It must be highly suspected in newborns or infants with diarrhea and severe electrolyte disorders. The diagnosis is based on clinical, endoscopic, histologic and eventually genetic findings. Treatment is supportive with intensive correction of electrolyte imbalances as well as parenteral nutrition. OBJECTIVE: To present a case report of congenital diarrhea identified as microvillous inclusion disease presenting in the neonatal period. CASE REPORT: Male patient currently 3 years of age, son of consanguineous parents. At 10 days of age presents a severe secretory diarrhea, requiring treatment in a critical care unit and parenteral nutrition. Initially he also presented with Fanconi syndrome, which improved afterwards. The suspicion of congenital microvillous inclusion was confirmed later by optic and electronic microscopy, and inmunohistochemistry. A succesful evolution was later achieved maintaining home parenteral nutrition after discharge. CONCLUSION: We present the first known case in Chile of congenital diarrhea due to microvillous inclusión disease and his evolution.

Enfermedad por inclusión microvellositaria como causa de diarrea congénita severa: caso clínico / Microvillous inclusion disease as a cause of severe congenital diarrhea: case report

Las diarreas congénitas son patologías graves de baja frecuencia y alta mortalidad. Se manifiestan durante los primeros días o meses de vida con severa diarrea, generando insuficiencia intestinal y dependencia de nutrición parenteral. Se debe sospechar ante un recién nacido o lactante con pérdidas masivas hidroelectrolíticas, y se diagnostican utilizando parámetros clínicos, endoscópicos, histológicos y eventualmente genéticos. El tratamiento es de soporte, con reposición hidroelectrolítica intensa y nutricional. OBJETIVO: Presentar un caso de diarrea congénita, identificada como Enfermedad por Inclusión Microvellositaria, de presentación neonatal. CASO CLÍNICO: Paciente varón edad actual 3 años, hijo de padres consanguíneos, quien debutó a los 10 días de vida con diarrea secretora severa, requiriendo ingreso a unidad de paciente crítico y nutrición parenteral permanente. Inicialmente además con síndrome de Fanconi, que luego se recupera. Se confirmó la sospecha de Enfermedad de Inclusión Microvellositaria utilizando microscopia óptica, electrónica e inmunohistoquímica. Se obtuvo una favorable evolución utilizando nutrición parenteral total (NPT) a domicilio. CONCLUSIONES: Se presenta el primer caso conocido en Chile de un paciente con diarrea congénita por inclusión microvellositaria manejado y su evolución.

Congenital diarrheas correspond to a severe and low frequency digestive disease, with a high mortality. They start a few days or months after birth, leading to intestinal insufficiency and dependence on parenteral nutrition. It must be highly suspected in newborns or infants with diarrhea and severe electrolyte disorders. The diagnosis is based on clinical, endoscopic, histologic and eventually genetic findings. Treatment is supportive with intensive correction of electrolyte imbalances as well as parenteral nutrition. OBJECTIVE: To present a case report of congenital diarrhea identified as microvillous inclusion disease presenting in the neonatal period. CASE REPORT: Male patient currently 3 years of age, son of consanguineous parents. At 10 days of age presents a severe secretory diarrhea, requiring treatment in a critical care unit and parenteral nutrition. Initially he also presented with Fanconi syndrome, which improved afterwards. The suspicion of congenital microvillous inclusion was confirmed later by optic and electronic microscopy, and inmunohistochemistry. A succesful evolution was later achieved maintaining home parenteral nutrition after discharge. CONCLUSION: We present the first known case in Chile of congenital diarrhea due to microvillous inclusión disease and his evolution.

Enigmatic in vivo GlcNAc-1-phosphotransferase (GNPTG) transcript correction to wild type in two mucolipidosis III gamma siblings homozygous for nonsense mutations.

Mucolipidosis (ML) III gamma is a rare autosomal-recessive disorder caused by pathogenic mutations in the GNPTG gene. GNPTG encodes the γ-subunit of GlcNAc-1-phosphotransferase that catalyzes mannose 6-phosphate targeting signal synthesis on soluble lysosomal enzymes. ML III gamma patients are characterized by missorting of lysosomal enzymes. In this report, we describe the probable occurrence of mRNA editing in two ML III gamma patients. Patients A and B (siblings) presented at the adult age with a typical clinical picture of ML III gamma, mainly compromising bone and joints, and high levels of lysosomal enzymes in plasma and low levels in fibroblasts. Both were found to be homozygous for c.-112C>G and c.328G>T (p.Glu110Ter) mutations in genomic DNA (gDNA) analysis of GNPTG. Analysis of complementary DNA (cDNA), however, showed normal genotypes for both patients. Low GNPTG mRNA expression was observed in both patients. The mRNA editing can explain the differences found in patients A and B regarding gDNA and cDNA analysis, and the mild clinical phenotype associated with homozygosity for a nonsense mutation. Our results suggest that mRNA editing can be more frequent than expected in monogenic disorders and that GNPTG analysis should be performed on gDNA.

Variable phenotype and severity of sialidosis expressed in two siblings presenting with ataxia and macular cherry-red spots.

Sialidosis is a rare lysosomal storage disease with a wide clinical spectrum ranging from nearly asymptomatic to severe presentations. We present two Brazilian siblings with sialidosis, the first patient with sialidosis type I, and the second with sialidosis type II. Our report reinforces the relevance of ophthalmologic evaluation in patients with early and late-onset ataxias, if an association with myoclonus or dysmorphic features is present or not. Also, we demonstrate that sialidosis might represent a single genetic entity with variable clinical expression through these two siblings.

Mucolipidosis II and III alpha/beta in Brazil: analysis of the GNPTAB gene.

UNLABELLED: Mucolipidosis II and III (MLII and MLIII) alpha/beta are rare autosomal recessive lysosomal storage diseases (LSDs) caused by pathogenic variations in the GNPTAB gene. GNPTAB gene codes for the α and ß subunits of phosphotransferase, the enzyme responsible for synthesis of the mannose-6-phosphate (M6P) marker that directs lysosomal enzymes to the lysosome. OBJECTIVES: The objective of this study is to identify sequence variations of the GNPTAB gene in Brazilian patients with MLII and MLIII alpha/beta. METHOD: Sequencing of the GNPTAB gene was performed in samples of gDNA extracted from the peripheral blood of patients with MLII/III diagnosed at a national reference center for LSDs. RESULTS: Twelve unrelated patients, from several regions of Brazil, were included in this study. Only one was born of consanguineous parents. All patients were found to carry at least one nonpathogenic variation. Nine causal sequence variations were found: c.242G>T (p.W81L); c.1123C>T (p.R375X); c.1196C>T (p.S399F); c.1208T>C (p.I403T); c.1514G>A (p.C505Y); c.1759C>T (p.R587X); c.2808A>G (p.Y937_M972del, novel mutation); c. 2269_2273delGAAAC (p.E757KfsX2, novel mutation); and c.3503_3504delTC (p.L1168QfsX5). Both pathogenic variations were identified in 8 of 12 patients; in four patients, only one pathogenic variation was identified. Mutation c.3503_3504delTC, located in exon 19, was the most frequent pathogenic variation found (n=11/24 alleles). The deleterious effect of the c.2808A>C mutation on splicing was confirmed by cDNA analysis. DISCUSSION/CONCLUSIONS: Our findings confirm that the GNPTAB gene presents broad allelic heterogeneity and suggests that, in Brazilian ML II and III patients, screening for mutations should begin at exon 19 of the GNPTAB gene. Further analyses will be conducted on patients in whom both pathogenic mutations have not been found in this study.

Oral findings in patients with mucolipidosis type III.

Mucolipidosis type III is a rare, autosomal recessive disorder, which is part of a group of storage diseases as a result of inborn error of lysosomal enzyme metabolism. It is characterized by the gradual onset of signs and symptoms affecting the physical and mental development as well as visual changes, heart, skeletal and joint. Although oral findings associated with mucolipidosis type II have been extensively reported, there is a shortage of information on mucolipidosis type III. This paper presents radiological and histological findings of multiple radiolucent lesions associated with impacted teeth in the jaw of a 16 year-old youngster with mucolipidosis type III.

Oral findings in patients with mucolipidosis type III

Mucolipidosis type III is a rare, autosomal recessive disorder, which is part of a group of storage diseases as a result of inborn error of lysosomal enzyme metabolism. It is characterized by the gradual onset of signs and symptoms affecting the physical and mental development as well as visual changes, heart, skeletal and joint. Although oral findings associated with mucolipidosis type II have been extensively reported, there is a shortage of information on mucolipidosis type III. This paper presents radiological and histological findings of multiple radiolucent lesions associated with impacted teeth in the jaw of a 16 year-old youngster with mucolipidosis type III.

A mucolipidose tipo III é uma doença rara, autossômica recessiva, que faz parte de um grupo de doenças de depósito, decorrentes do erro inato do metabolismo das enzimas lisossômicas. Caracteriza-se pelo aparecimento progressivo de sinais e sintomas com repercussão no desenvolvimento físico e mental, bem como alterações visuais, cardíacas, esqueléticas e articulares. Apesar de achados bucais estarem bem relatados em associação à mucolipidose tipo II, esse artigo descreve achados radiográficos e histológicos de múltiplas lesões radiolúcidas, associadas a dentes inclusos nos maxilares, em uma jovem de 16 anos de idade com mucolipidose tipo III.

[Mucolipidoses type IV in a patient with mapuche ancestry]. / Mucolipidosis tipo IV en una paciente con ancestros mapuches. Caso clínico.

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 of ataxic 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 differential diagnosis of cerebral palsy associated with loss of acquired skills and progressive visual impairment. Electron microscopy of skin or conjunctiva is a useful diagnostic test. Suspicion of ML-IV must not be restricted to Ashkenazi Jewish population.

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.

Correlación clínico-patológica de enfermedades cutáneas de depósito lisosomal (I parte) / Clinico-pathological correlation of lysosomal storage skin diseases (part I)

Las enfermedades de depósito lisosomal corresponden a alteraciones congénitas del metabolismo, las cuales se heredan de forma autosómica recesiva y están caracterizadas por el déficit específico de una hidrolasa lisosomal y por el acúmulo de su sustrato en varios tejidos del organismo. Dependiendo de la naturaleza bioquímica del sustrato acumulado, éstas pueden dividirse en esfingolipidosis, oligosacaridosis, mucolipidosis, mucopolisacaridosis y otras.

Lysosomal storage diseases are autosomal recessive disorders of inborn errors of metabolism, characterized by a deficiency in a specific lysosomal hydrolase and by accumulation of its specific substrate in various body tissues. Depending on the basis of the biochemical nature of the accumulated substrate, they can be divided in sphingolipidoses, oligosaccharidoses, mucolipidoses, mucopolysaccharidoses, and others.