Understanding the ecosystem of patients with lysosomal storage diseases in Spain: a qualitative research with patients and health care professionals

Background Lysosomal Storage Diseases (LSDs) are a group of Rare Diseases (RDs) caused by lysosomal enzyme deficiencies. Patients with LSDs suffer from a wide range of symptoms with a strong impact in their daily routines. In this study we aimed to explore the impact of the disease on the lives of patients with four LSDs, as well as how they experience Patient Journey from diagnosis to follow up. Unmet Needs (UNs) perceived by patients and clinicians were assessed to have a better understanding of which initiatives could improve LSDs management and especially those that could result in an improvement of patients’ quality of life. Methods Qualitative research was the research methodology selected for the study. It provides plentiful and holistic insights into people’s views and actions. The study was conducted through in-depth face-to-face semi-structured interviews. Results In total, 20 patients and 25 Health Care Professionals (HCPs) from different Spanish regions were interviewed. Patients perceived that the highest impact of the LSDs was on their daily routines, specifically on their emotional side, their work/school environment, their family and their social life. Regarding the Patient Journey experience, the worst perceived stage was the pre-diagnosis, where patients only reported negative perceptions, being the delay in diagnosis and misdiagnosis the most commented issues. On the contrary, the follow-up stage was the one with less negative perceptions. Overall, patients and HCPs agreed on the priority UNs, such as accelerating diagnosis, reducing bureaucracy for the treatment access and a more coordinated attention for the patients, not only among different physicians but also with other professionals such as genetic counselors or social workers. Conclusions Our data shows that there are still UNs to be addressed from the perspective of patients and HCPs. The main UN is accelerating diagnosis, which could be achieved by medical awareness and education, according to clinicians. A more comprehensive disease management was another main point to be worked on to improve LSD-patient experience and quality of life.

Peripheral neuropathy as a very rare symptom in a patient with Niemann–Pick type C with negative enzymatic evaluation: a case report

Background Niemann–Pick is a rare metabolic disease distinguished by lysosomal storage defects. This disease is characterized by sphingomyelinase acid deficiency, causing its accumulation in various organs such as the kidneys, spleen, liver, brain, and nerves. Niemann–Pick disease is categorized into four groups: A, B, C, and D. Peripheral neuropathy is an extremely rare complication in patients with Niemann–Pick type C, which certainly leads to neurologic deterioration. Case presentation We report a case of Niemann–Pick type C disease in a 3-year-old Iranian Azeri female patient who was hospitalized twice. The first time was at 1 month of age with symptoms of splenomegaly, jaundice, and elevated liver enzymes, and the second time was at around age 2 for loss of mental and physical abilities. The patient presented with failure to thrive. According to paraclinical examinations, mildly delayed myelination along with a nonspecific periventricular hypersignal intensity was seen. Interestingly, the patient’s Niemann–Pick type C enzymatic function was evaluated twice and was negative on both occasions, while she was positive for NPC1 and NPC2 gene examinations. Conclusions In this study, despite the enzymatic study being negative, Niemann–Pick type C disease was finally confirmed, revealing the importance of mutations in Niemann–Pick type C pathogenesis. Besides, peripheral neuropathy was diagnosed in this patient as a very rare symptom of Niemann–Pick type C.

Release of acidic store calcium is required for effective priming of the NLRP3 inflammasome

The lysosome is a dynamic signaling organelle that is critical for cell functioning. It is a regulated calcium store that can contribute to Ca2+-regulated processes via both local calcium release and more globally by influencing ER Ca2+release. Here, we provide evidence from studies of an authentic mouse model of the lysosomal storage disease Niemann-Pick Type C (NPC) that has reduced lysosomal Ca2+ levels, and genetically modified mice in which the two-pore lysosomal Ca2+ release channel family are deleted that lysosomal Ca2+ signaling is required for normal pro-inflammatory responses. We demonstrate that production of the pro-inflammatory cytokine IL-1beta via the NLRP3 inflammasome is significantly reduced in murine Niemann-Pick Type C, the inhibition is selective because secretion of TNF alpha is not diminished, and it is a consequence of inefficient inflammasome priming. Synthesis of precursor ProIL-1 beta is significantly reduced in macrophages genetically deficient in the lysosomal protein Npc1, which is mutated in most clinical cases of NPC, and in wild type cells in which Npc1 activity is pharmacologically inhibited. Comparable reductions in ProIL-1 beta generation were measured in vitro and in vivo by macrophages genetically altered to lack expression of the two-pore lysosomal Ca2+ release channels Tpcn1 or Tpcn2. These data demonstrate a requirement for lysosome-dependent Ca2+ signaling in the generation of specific pro-inflammatory responses.

A CASE REPORT OF JUVENILE FORM OF METACHROMATIC LEUKODYSTROPHY

Metachromatic Leukodystrophy is a lysosomal storage autosomal recessive disease characterized by arylsulphatase enzyme deficiency, with central and peripheral demyelination. We report a case of a 15-year-old girl with 6 months history of progressive muscular weakness, poor school performance, gradual memory loss and gait disturbance. Neurological examination was grossly normal, except mild muscle wastage in both upper and lower limbs and slight reduction of power globally in all limbs. Routine bloods including a lumbar puncture was normal and the diagnosis of metachromatic leukodystrophy was made on the findings of magnetic resonance imaging (MRI) brain.

Insights Into the COVID-19 Infection Related to Inherited Metabolic Diseases

People with respiratory problems and people prone to decompensations are particularly vulnerable to COVID-19. These characteristics are often present in patients with inherited metabolic diseases (IMDs). It is therefore conceivable that patients with IMDs are at a greater risk of infection and may present a more serious form of COVID-19 disease. Currently available data about the impact of COVID-19 on patients suffering from IMDs are very scarce and no study has been able to confirm this hypothesis. In this chapter, the authors have tried to show that the severity of COVID-19 infection in patients with IMDs is specific to the group that the disease belongs. Indeed, lysosomal storage diseases caused by impaired degradation and accumulation of metabolites in lysosomes leads to dysfunction of lysosomal and possible impairment of the COVID-19 egress process. The fact that COVID-19 disease may be considered itself as an IMD was also discussed to highlight the interference which can exist between COVID-19 disease and IMDs in a patient.

Drosophila D-idua Reduction Mimics Mucopolysaccharidosis Type I Disease-Related Phenotypes

Deficit of the IDUA (α-L-iduronidase) enzyme causes the lysosomal storage disorder mucopolysaccharidosis type I (MPS I), a rare pediatric neurometabolic disease, due to pathological variants in the IDUA gene and is characterized by the accumulation of the undegraded mucopolysaccharides heparan sulfate and dermatan sulfate into lysosomes, with secondary cellular consequences that are still mostly unclarified. Here, we report a new fruit fly RNAi-mediated knockdown model of a IDUA homolog (D-idua) displaying a phenotype mimicking some typical molecular features of Lysosomal Storage Disorders (LSD). In this study, we showed that D-idua is a vital gene in Drosophila and that ubiquitous reduction of its expression leads to lethality during the pupal stage, when the precise degradation/synthesis of macromolecules, together with a functional autophagic pathway, are indispensable for the correct development to the adult stage. Tissue-specific analysis of the D-idua model showed an increase in the number and size of lysosomes in the brain and muscle. Moreover, the incorrect acidification of lysosomes led to dysfunctional lysosome-autophagosome fusion and the consequent block of autophagy flux. A concomitant metabolic drift of glycolysis and lipogenesis pathways was observed. After starvation, D-idua larvae showed a quite complete rescue of both autophagy/lysosome phenotypes and metabolic alterations. Metabolism and autophagy are strictly interconnected vital processes that contribute to maintain homeostatic control of energy balance, and little is known about this regulation in LSDs. Our results provide new starting points for future investigations on the disease’s pathogenic mechanisms and possible pharmacological manipulations.

A Journey towards Understanding the Molecular Pathology and Developing Therapies for Lysosomal Storage Disorders

Lysosomal storage disorders (LSDs) are rare, monogenic diseases characterized by aberrant lysosomes with storage material [...]