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.

Articular Syndrome Characteristics in Children with Mucopolysaccharidosis Type I

Background. Mucopolysaccharidosis type I is disease from the group of lysosomal storage disease developing due to mutations in the IDUA gene. It leads to the accumulation of glycosaminoglycans (GAGs) in organs and tissues. Joints damage in this disease is systemic and progressive.Objective. The aim of the study. Nowadays, relevant issue is to investigate the effects of various types of pathogenetic therapy on the state of the osteoarticular system in patients with severe and mild phenotypes of MPS I to prevent further progression of joint pathology.Methods. The study included 46 patients diagnosed with “mucopolysaccharidosis type I”. 35 children had severe phenotype (Hurler syndrome) and 11 — with mild phenotypes (Hurler-Scheie and Scheie syndromes). The onset age of clinical manifestations in osteoarticular system, the state of large and small joints, and the presence of cervical stenosis according to the therapy were evaluated in these patients.Results. The osteoarticular system pathology can be usually revealed in all patients with MPS I, in both mild and severe phenotypes. The contractures of shoulder, ulnar, wrist, and small hand joints have been revealed in most patients with Hurler syndrome, regardless of the administered therapy. Hip joints pathology was observed in children who was administered with: enzyme replacement therapy (ERT) — in 46.7% of cases, hematopoietic stem cell transplantation (HSCT) in combination with ERT — in 34.4% of cases. Patients with Hurler syndrome administered with HSCT in combination with ERT had cervical stenosis statistically significantly more rarely (p = 0.018) compared to patients treated with ERT only. Patients with Hurler syndrome who were on ERT had statistically significantly lower growth rates than patients after HSCT in combination with ERT. Lesions in ulnar, wrist, knee and small hand joints were the most common in children with mild phenotypes (in 90% of cases).Conclusion. Combined therapy (HSCT and ERT) in patients with Hurler syndrome reduces severe manifestations in osteoarticular system.

Mucopolysaccharidosis Type II: A Kenyan Case Series

Hunter syndrome, or mucopolysaccharidosis type 2 (MPS2), is a lysosomal storage disorder associated with the involvement of multiple organs such as the central nervous system, hepatomegaly, musculoskeletal, respiratory, cardiac, and hearing. This is due to the accumulation of glycosaminoglycans in body tissues leading to organ failure. Since the laboratories in Kenya do not screen for metabolic diseases, there is the likelihood of assumption that these patients do not exist. These first cases were referred from the eastern part of Kenya where the majority of inhabitants are from the same ethnic community. It was noted that there was increased mortality among boys below the age of 20 years, and hence, the families sought for help in the national referral and teaching hospital. The case series is meant to show that these cases exist and the majority of the patients may be dying before the diagnosis is made. There are no data on MPS2 from Kenya, and the prevalence and incidence are unknown. In this retrospective study, we present a case series of 6 Kenyan boys with MPS2 from a national referral hospital. They were part of 17 patients who had had their blood analyzed for metabolic diseases. All of them were symptomatic with varying degrees of central nervous system involvement. They had undetectable levels of iduronate-2-sulfatase (I2S) enzyme, and three genetic mutations were detected in the IDS gene.

Enzyme Replacement Therapy with Idursulfase in Patients with Mucopolysaccharidosis Type II: Literature Review

Mucopolysaccharidosis type II (MPS II; Hunter syndrome) is X-linked hereditary disease from the group of lysosomal storage disease. Its prevalence is 3–7 cases per 1 million live-born boys. MPS II occurs due to the deficiency of iduronate-2-sulfatase enzyme because of pathological changes in the structure of the IDS gene. Enzyme deficiency leads to the accumulation of glycosaminoglycans (GAGs), dermatan sulfate and heparan sulfate, in lysosomes. This leads to the damage of various organs and systems in the body with further development of clinical picture of the disease: coarse face, recurrent infections of upper respiratory tract, hearing loss up to deafness, cardiovascular and respiratory systems pathologies, hepatosplenomegaly, musculoskeletal system abnormalities, low growth, central nervous system damage. Enzyme replacement therapy with idursulfase, that was introduced in clinical practice 15 years ago, has significantly changed the quality of life of these patients. Idursulfase is purified form of natural lysosomal enzyme iduronate-2-sulfatase obtained via human cell line. Exogenous enzyme entry promotes GAGs catabolism in cells. This article provides outcomes analysis of foreign and Russian studies on the efficacy and safety of this medication, and its effect on MPS II patients survivability.

Complex Communication Needs of a Child with Dandy-Walker Syndrome and Mucopolysaccharidosis Type II Case Study

There exist few publications describing the cases of children diagnosed with two rare diseases. Most of them are medical case studies. The purpose of the research was to describe the complex communication needs of a child and the resulting needs in the area of me as a person and in the home, social, educational, therapeutic and medical environment. The research involved a boy in early school age diagnosed with the Dandy-Walker syndrome and mucopolysaccharidosis type II (Hunter syndrome). The research was embedded in qualitative orientation using an individual case study. The research was conducted over a period of four years (2016 to 2020). The complex communication needs diagnosed in the boy triggered the following needs in the area of “me as a person”: to notice the effects of one’s actions, to have a sense of being a member of a group, to engage in activities that will help develop one’s own competencies and gain experience, and to be included in group activities. The research suggests that all of the above mentioned needs exist in the home and social environment area. In terms of education, it was determined that there is no need for a teaching assistant/aide who would know alternative methods of communication and could adapt the classroom to multimodal communication and train other persons. In terms of therapy, there was no need to create a controlled space in an institution, as therapy, the same as education, takes place in the boy’s home. In terms of medical care, Adam has all the above mentioned needs.