Mucolipidosis: A mimicker of juvenile idiopathic arthritis.

Juvenile idiopathic arthritis is the most common form of chronic arthritis in children and at times misdiagnosed in those presenting with arthropathy secondary to non-inflammatory causes. The overlap of symptoms often pose a diagnostic challenge for clinicians. This mostly results in a delayed diagnosis subjecting children to unnecessary use of long-term immunosuppressants and disease-modifying drugs. We present the case of a 9-year-old boy who was previously misdiagnosed as a case of juvenile idiopathic arthritis. Detailed evaluation later led to the diagnosis of mucolipidosis (type III) which was confirmed on genetic testing. Emphasis on detailed history and clinical examination including the subtle hints like lack of signs of inflammation, family history, no morning stiffness and normal inflammatory markers should be picked up to make a timely diagnosis. In today's era of genetic testing and diagnosis, it is prudent to offer these tests for such patients to make an accurate diagnosis and prognosticate them for the long-term outcome.

The High Association of Ophthalmic Manifestations in Individuals With Mucolipidosis Type IV.

PURPOSE: To present a case report of mucolipidosis type IV (ML4) and review the literature for all of the ophthalmic abnormalities associated with this disease. METHODS: A systematic review of the literature using PubMed/Medline was conducted, and with the addition of the current case report, the eye and ocular adnexa findings of 93 patients with ML4 are summarized. RESULTS: The most common ophthalmic findings reported among the 93 patients included corneal clouding (90.3%), strabismus (58.1%), optic nerve pallor (52.2%), retinal dystrophy/pigmentary changes (50.5%), and retinal vascular attenuation (38.9%). Other less commonly reported findings included nystagmus, photophobia, ocular pain, excessive lacrimation, ptosis, and cataracts. CONCLUSIONS: The ophthalmic findings discussed in the current case report and literature review serve as indicators for ML4. Early diagnosis of ML4 is important in forming a multidisciplinary management plan, genetic counseling strategy, and maximizing the visual development of affected individuals. [J Pediatr Ophthalmol Strabimus. 2022;59(5):332-337.].

Neuraminidase 1 deficiency attenuates cardiac dysfunction, oxidative stress, fibrosis, inflammatory via AMPK-SIRT3 pathway in diabetic cardiomyopathy mice.

Diabetic cardiomyopathy (DCM) is associated with oxidative stress and augmented inflammation in the heart. Neuraminidases (NEU) 1 has initially been described as a lysosomal protein which plays a role in the catabolism of glycosylated proteins. We investigated the role of NEU1 in the myocardium in diabetic heart. Streptozotocin (STZ) was injected intraperitoneally to induce diabetes in mice. Neonatal rat ventricular myocytes (NRVMs) were used to verify the effect of shNEU1 in vitro. NEU1 is up-regulated in cardiomyocytes under diabetic conditions. NEU1 inhibition alleviated oxidative stress, inflammation and apoptosis, and improved cardiac function in STZ-induced diabetic mice. Furthermore, NEU1 inhibition also attenuated the high glucose-induced increased reactive oxygen species generation, inflammation and, cell death in vitro. ShNEU1 activated Sirtuin 3 (SIRT3) signaling pathway, and SIRT3 deficiency blocked shNEU1-mediated cardioprotective effects in vitro. More importantly, we found AMPKα was responsible for the elevation of SIRT3 expression via AMPKα-deficiency studies in vitro and in vivo. Knockdown of LKB1 reversed the effect elicited by shNEU1 in vitro. In conclusion, NEU1 inhibition activates AMPKα via LKB1, and subsequently activates sirt3, thereby regulating fibrosis, inflammation, apoptosis and oxidative stress in diabetic myocardial tissue.

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

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

Neurophysiolgical implications in sialidosis type 1: a case report.

Sialidosis is a rare autosomal recessive hereditary disease caused by NEU1 gene mutations. A 25-year-old woman developed generalized tonic-clonic seizures since teenage, followed by progressive visional decline and limb myoclonus. Her sister had similar presentations. Both patients were products of a consanguineous marriage. Electroencephalography (EEG) revealed extensive paroxysmal spiky beta brush. Somatosensory evoked potentials (SEP) after stimulation of median nerves demonstrated giant SEP and C-reflex support the cortical origin of myoclonus. Genetic tests confirmed that both sisters carried the known pathogenic homozygous mutation of c.544A > G in exon 3 of the NEU1 gene. The diagnosis of sialidosis type 1 was then made. This suggests that neurophysiological abnormalities, especially spiky beta brush on EEG, might facilitate the early diagnosis of sialidosis type 1.

Expanding the clinical spectrum in trichohepatoenteric syndrome.

Trichohepatoenteric syndrome (THES) is a very rare autosomal recessive genetic disorder, which is characterized by intractable diarrhea during infancy, dysmorphic features, immunodeficiency, and a failure to thrive. There are still significant difficulties for patients and clinicians in terms of the management of THES, even though its molecular basis has been uncovered in the last decade. In this article, we have presented two cases relating to siblings that have been diagnosed with the condition. Concerning one of the patients, we described a novel variation (c.2114 + 5G > A) in the TTC37 gene and a mild clinical course; meanwhile, the other one was clinically diagnosed with THES at 17 years of age, but they had seizures and died suddenly. These cases expand the spectrum of clinical findings in relation to THES.

Mucolipidosis â ¡ and III with neurological symptoms due to spinal cord compression.

In mucopolysaccharidoses (MPS), spinal cord compression (SCC) resulting from glycosaminoglycan (GAG) accumulation is a critical complication that can cause significant neurological and respiratory morbidities. However, clinically similar disorders such as mucolipidosis types II and III (ML) with SCC have been scarcely reported. Herein, we report four patients with ML who had SCC. Brain MRI revealed progressive spinal canal stenosis and SCC. In addition, T2-weighted high signal changes in the cervical cord were detected in two cases. Severe cases of SCC were detected as early as 1 year of age. All cases had respiratory problems. One case showed severe hypoxia and another, severe sleep apnea. In two cases, respiratory insufficiency and tetraplegia rapidly progressed as SCC progressed. Then, the patients became bedridden and needed artificial ventilation. In addition, two of the four patients died of respiratory failure. The autopsy of one patient revealed a compressed cervical cord and marked dura mater thickening due to GAG accumulation. These findings suggest that the accumulation of substrates in the dura mater caused SCC in the patients with ML. Our cases indicate that SCC is expected to be a common and critical complication of ML and MPS. MRI evaluation of cervical involvements and careful clinical observation are required in patients with ML.

Cardiovascular involvement in alpha-n-acetyl neuraminidase deficiency syndromes (sialidosis type I and II).

Sialidosis, a rare autosomal recessive disorder, is caused by a deficiency of NEU1 encoded enzyme alpha-N-acetyl neuraminidase. We report a premature male with neonatal-onset type II sialidosis which was associated with left ventricular dysfunction. The clinical presentation and subsequent progression which culminated in his untimely death at 16 months of age are succinctly described. Early-onset cardiovascular involvement as noted in this patient is not well characterised. The case report is supplemented by a comprehensive review of the determinants, characteristics, and the clinical course of cardiovascular involvement in this rare condition.

Hip disease in Mucopolysaccharidoses and Mucolipidoses: A review of mechanisms, interventions and future perspectives.

The hips are frequently involved in inheritable diseases which affect the bones. The clinical and radiological presentation of these diseases may be very similar to common hip disorders as developmental dysplasia of the hip, osteoarthritis and avascular necrosis, so the diagnosis may be easily overlooked and treatment may be suboptimal. Mucopolysaccharidosis (MPS) and Mucolipidosis (ML II and III) are lysosomal storage disorders with multisystemic involvement. Characteristic skeletal abnormalities, known as dysostosis multiplex, are common in MPS and ML and originate from intra-lysosomal storage of glycosaminoglycans in cells of the cartilage, bones and ligaments. The hip joint is severely affected in MPS and ML. Hip pathology results in limitations in mobility and pain from young age, and negatively affects quality of life. In order to better understand the underlying process that causes hip disease in MPS and ML, this review first describes the normal physiological (embryonic) hip joint development, including the interplay between the acetabulum and the femoral head. In the second part the factors contributing to altered hip morphology and function in MPS and ML are discussed, such as abnormal development of the pelvic- and femoral bones (which results in altered biomechanical forces) and inflammation. In the last part of this review therapeutic options and future perspectives are addressed.

The rare reason of pain in hip girdle: Mucolipidosis type 3 gamma.

BACKGROUND: Mucolipidosis type 3 gamma (ML-IIIγ) is an autosomal recessive, rare and slowly progressive lysosomal storage disease. Short stature, restricted joint mobility, thick skin, and flat face with mildly coarse features are major clinical findings. It usually manifests in the third year. With advancing age, claw hand deformities, carpal tunnel syndrome, and scoliosis may develop. Morbidity is determined mainly by skeletal involvement. N-acetyl glucosamine-1 phospotransferase enzyme is composed of 2α, 2ß and 2γ subunits. The active enzyme is essential in the transport of hydrolases to the lysosomes, via addition of mannose-6-phosphate in the Golgi apparatus. GNPTG gene encodes the γ2 subunits, and biallelic mutations cause ML-IIIγ. CASE: A previously healthy 14-year-old male patient had leg pain after the age of nine, and was admitted with short stature, mild coarse face, pectus deformity, digital stiffness, scoliosis, genu valgum and mitral valve prolapse. He did not have intellectual disability or corneal clouding. Radiographs showed irregularities in the acetabular roof and proximal epiphyses of the femur and irregularities in the end plates of vertebral bodies. A novel homozygous missense variant in the exon 5 of GNPTG, c.316G > T, confirmed the diagnosis of ML- IIIγ. Juvenile idiopathic arthritis (JIA), progressive pseudorheumatoid dysplasia (PPRD), ML-II, ML-IIIαß, galactosialidosis and mucopolysaccharidosis should be considered in the differential diagnosis. CONCLUSIONS: ML-IIIγ should be kept in mind in populations with high consanguineous marriage rates or with possible founder effect, in patients with short stature and skeletal destruction. Genetic tests should be planned for a definitive diagnosis.

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

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

A sialidosis type I cohort and a quantitative approach to multimodal ophthalmic imaging of the macular cherry-red spot.

AIM: To describe the ophthalmologic findings on the largest cohort of patients with sialidosis type I due to deficiency of the lysosomal sialidase, neuraminidase 1 (NEU1) and to introduce a quantitative neuroretinal image analysis approach to the associated 'macular cherry-red spot'. METHODS: Seven patients with sialidosis type I (mutations in NEU1) and one with galactosialidosis (mutations in CTSA) were included. All patients underwent detailed ophthalmological examinations. The reflectivity of macular optical coherence tomography (OCT) was measured using greyscale analysis (Fiji) and compared with age-matched healthy volunteers. Four patients were evaluated over a time of 1.5+0.5 years. RESULTS: The mean age of the patients at their first visit was 27.5+9.8 years. All patients had a macular cherry-red spot, clear corneas and visually non-significant lenticular opacities. The mean visual acuity was LogMar 0.4 (20/50)+0.4 (20/20 to 20/125). Six patients had good visual function. Optic atrophy was present in two individuals with reduced acuity. A significant increase in macular reflectivity was present in all patients compared to age-matched controls (p<0.0001). CONCLUSION: Most of our patients (75%) have preserved visual acuity, even in adulthood. The presence of optic atrophy is associated with poor visual acuity. Increased macular reflectivity by OCT greyscale measurements is noted in all patients, although the underlying biological basis is unknown. These findings complement the current methods for examining and monitoring disease progression, especially in patients for whom visualisation of the cherry-red spot is not entirely clear. TRIAL REGISTRATION NUMBER: NCT00029965.

Dilated cardiomyopathy in mucolipidosis type 2.

Mucolipidosis II and III are lysosomal storage diseases caused by pathogenetic mutations in GNPTAB and GNPTG genes which cause an impaired activity of the lysosomal hydrolase N-acetylglucosamine- 1-phosphotransferase, a key enzyme in the synthesis of the mannose-6-phosphate targeting signals on lysosomal enzymes. Patients with MLII alpha/beta present coarse facial features, cessation of statural growth, important skeletal manifestations, impaired neuromotor development and cardiorespiratory involvement. All children appear to have cardiac involvement, but severe dilated cardiomyopathy is uncommon. In this report we describe the case of an 11-month-old girl who is affected by a MLII. Analysis of the GNPTAB gene identified at a heterozygous level the previously described gene variants c. 2693delA p(Lys898Serfs*13) and c. 2956C>T p(Arg986Cys). Her main clinical features were coarse face with gingival hypertrophy, dysostosis multiplex, recurrent respiratory infection and an early onset of dilated cardiomyopathy, an uncommon feature for MLII. To our knowledge, dilated cardiomyopathy has been previously described in literature in only two cases of MLII and in one patient affected by MLIII.

Distinct Modes of Balancing Glomerular Cell Proteostasis in Mucolipidosis Type II and III Prevent Proteinuria.

BACKGROUND: The mechanisms balancing proteostasis in glomerular cells are unknown. Mucolipidosis (ML) II and III are rare lysosomal storage disorders associated with mutations of the Golgi-resident GlcNAc-1-phosphotransferase, which generates mannose 6-phosphate residues on lysosomal enzymes. Without this modification, lysosomal enzymes are missorted to the extracellular space, which results in lysosomal dysfunction of many cell types. Patients with MLII present with severe skeletal abnormalities, multisystemic symptoms, and early death; the clinical course in MLIII is less progressive. Despite dysfunction of a major degradative pathway, renal and glomerular involvement is rarely reported, suggesting organ-specific compensatory mechanisms. METHODS: MLII mice were generated and compared with an established MLIII model to investigate the balance of protein synthesis and degradation, which reflects glomerular integrity. Proteinuria was assessed in patients. High-resolution confocal microscopy and functional assays identified proteins to deduce compensatory modes of balancing proteostasis. RESULTS: Patients with MLII but not MLIII exhibited microalbuminuria. MLII mice showed lysosomal enzyme missorting and several skeletal alterations, indicating that they are a useful model. In glomeruli, both MLII and MLIII mice exhibited reduced levels of lysosomal enzymes and enlarged lysosomes with abnormal storage material. Nevertheless, neither model had detectable morphologic or functional glomerular alterations. The models rebalance proteostasis in two ways: MLII mice downregulate protein translation and increase the integrated stress response, whereas MLIII mice upregulate the proteasome system in their glomeruli. Both MLII and MLIII downregulate the protein complex mTORC1 (mammalian target of rapamycin complex 1) signaling, which decreases protein synthesis. CONCLUSIONS: Severe lysosomal dysfunction leads to microalbuminuria in some patients with mucolipidosis. Mouse models indicate distinct compensatory pathways that balance proteostasis in MLII and MLIII.

Clinical and genetic characteristics of type I sialidosis patients in mainland China.

OBJECTIVE: Type I sialidosis (ST-1) is a rare autosomal recessive inherited disorder. To date, there has been no study on ST-1 patients in mainland China. METHODS: We reported in detail the cases of five Chinese ST-1 patients from two centers, and summarized all worldwide cases. Then, we compared the differences between Chinese and foreign patients. RESULTS: A total of 77 genetically confirmed ST-1 patients were identified: 12 from mainland China, 23 from Taiwan, 10 from other Asian regions, and 32 from European and American regions. The mean age of onset was 16.0 ± 6.7 years; the most common symptoms were myoclonus seizures (96.0%), followed by ataxia (94.3%), and blurred vision (67.2%). Compared to other groups, the onset age of patients from mainland China was much younger (10.8 ± 2.7 years). The incidence of visual impairment was lower in patients from other Asian regions than in patients from mainland China and Taiwan (28.6% vs. 81.8%-100%). Cherry-red spots were less frequent in the Taiwanese patients than in patients from other regions (27.3% vs. 55.2%-90.0%). Furthermore, 48 different mutation types were identified. Chinese mainland and Taiwanese patients were more likely to carry the c.544A > G mutation (75% and 100%, respectively) than the patients from other regions (only 0%-10.0%). Approximately 50% of Chinese mainland patients carried the c.239C > T mutation, a much higher proportion than that found in the other populations. In addition, although the brain MRI of most patients was normal, 18 F-FDG-PET analysis could reveal cerebellar and occipital lobe hypometabolism. INTERPRETATION: ST-1 patients in different regions are likely to have different mutation types; environmental factors may influence clinical manifestations. Larger studies enrolling more patients are required.

Lysosomal storage disease spectrum in nonimmune hydrops fetalis: a retrospective case control study.

OBJECTIVES: Nonimmune hydrops fetalis (NIHF) accounts for 90% of hydrops fetalis cases. About 15% to 29% of unexplained NIHF cases are caused by lysosomal storage diseases (LSD). We review the spectrum of LSD and associated clinical findings in NIHF in a cohort of patients referred to our institution. METHODS: We present a retrospective case-control study of cases with NIHF referred for LSD biochemical testing at a single center. Cases diagnosed with LSD were matched to controls with NIHF and negative LSD testing and analyzed according to the STROBE criteria to the extent the retrospective nature of this study allowed. RESULTS: Between January 2006 and December 2018, 28 patients with NIHF were diagnosed with a LSD. Eight types of LSD were diagnosed: galactosialidosis 8/28 (28.6%), sialic acid storage disease (SASD) 5/28 (17.9%), mucopolysaccharidosis VII 5/28 (17.9%), Gaucher 4/28 (14.3%), sialidosis 2/28 (7.1%), GM1 gangliosidosis 2/28 (7.1%), Niemann-Pick disease type C 1/28 (3.6%), and mucolipidosis II/III 1/28 (3.6%). Associated clinical features were hepatomegaly 16/21 (76.2%) vs 22/65 (33.8%), P < .05, splenomegaly 12/20 (60.0%) vs 14/58 (24.1%), P < .05, and hepatosplenomegaly 10/20 (50.0%) vs 13/58 (22.4%) P < .05. CONCLUSION: The most common LSD in NIHF were galactosialidosis, SASD, mucopolysaccharidosis VII, and Gaucher disease. LSD should be considered in unexplained NIHF cases, particularly if hepatomegaly, splenomegaly, or hepatosplenomegaly is visualized on prenatal ultrasound.

Novel compound heterozygous MCOLN1 mutations identified in a Japanese girl with severe developmental delay and thin corpus callosum.

Mucolipidosis type IV (MLIV) is a rare lysosomal storage disorder causing severe psychomotor developmental delay and progressive visual impairment. MLIV is an autosomal recessive disease caused by mutations in MCOLN1, which encodes for mucolipin-1. Here, we report a case of a 4-year-old Japanese girl with severe intellectual disability and motor deficits. Brain magnetic resonance imaging showed signal abnormalities in the white matter and thinning of the corpus callosum. Whole-exome sequencing was performed on the proband and her parents, and novel compound heterozygous mutations at c.936_938del (p.Phe313del) and c.1503dupC (p.Ile502Hisfs*106) in MCOLN1 (NM_020533.2) were identified in the proband. Additional biochemical examinations revealed elevated serum gastrin level and iron deficiency anemia, leading to the diagnosis of MLIV. More reports of such pathogenic mutations are expected to broaden the understanding of the channel function of mucolipin-1 and genotype-phenotype correlations.