Orphanet Journal of Rare Diseases最新文献

Background: Arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome, a rare autosomal recessive disorder, exhibits genetic heterogeneity with the VIPAS39 gene pathological variants being a distinct contributor.

Results: We present two related patients from Kosovo, describing the clinical, genetic, and therapeutic aspects of the syndrome. The identified novel VIPAS39 pathological variants (c.762G > A; c.1064_1082delinsAGTG) emphasize the complex phenotypic expression of ARC syndrome. A systematic literature review identified 8 VIPAS39-related ARC cases with notable variability in clinical features. Prognostically, patients fell into severe and milder groups, with some reaching adolescence. Our report aligns with others noting milder ARC courses and emphasizes the value of genetic testing, especially in atypical presentations. Challenges included incomplete literature data, early mortality affecting diagnostic workup, and limited VIPAS39-related ARC cases. Comparisons with the more prevalent VPS33B pathological variants revealed no distinct clinical differences.

Conclusion: Our study expands understanding of ARC syndrome, highlighting its genetic diversity and clinical variability. Milder presentations underscore diagnostic challenges and the potential prevalence of undiagnosed cases. Increased awareness and comprehensive genetic testing are crucial for early and accurate diagnosis.

Background: Mucopolysaccharidosis (MPS) type 1 S and type 2 are rare lysosomal storage disorders characterized by impaired enzyme production, resulting in glycosaminoglycans accumulation within lysosomes. Enzyme Replacement Therapy (ERT) with laronidase and idursulfase are first line treatments, respectively. However, infusion-related hypersensitivity reactions (HR) may lead to ERT discontinuation. Thus, desensitization can be performed to restore ERT.

Methods: We report on a two-year follow-up after a combined desensitization approach in two MPS patients experiencing HR to ERT. This approach consists of intravenous rapid desensitization combined with the subcutaneous allergen immunotherapy-like desensitization with the culprit recombinant enzyme.

Results: The first patient, suffering from MPS type I, underwent to the combined desensitization approach, and subsequently tolerated weekly standard laronidase infusions for 13 months when HR occurred again. Then, a monthly omalizumab (anti-IgE monoclonal antibody) administration was implemented allowing the patient to restore ERT. The second patient, diagnosed with MPS type 2, was subjected to a similar combined desensitization strategy with idursulfase, and achieved a total desensitization after one year, confirmed by negative skin tests. Thus, he continued standard ERT infusions without HR occurrence.

Conclusion: The combined desensitization approach proved effective in conferring immunotolerance for at least one year in both MPS patients, also demonstrated by the negative skin tests in one patient. However, when immunotolerance to ERT is lost, omalizumab administration can be a valid option in restoring ERT.

Background: Epidermolysis bullosa (EB) comprises a group of genetically and clinically heterogeneous diseases characterized by skin fragility and blistering. EB is incurable, and treatment consists of preventing blisters in addition to painful and time consuming skin care, often performed by the parents, in addition to monitoring other symptoms in cases of severe EB.

Results: The purpose of this study was to explore parental experiences of caring for a child with EB. Data were collected from semi-structured interviews, and analyzed through reflexive thematic analysis. The sample consisted of 15 parents. Our analysis revealed three main themes: Becoming a self-taught provider of home-based skin care; Balancing roles; and Ahead of every challenge. The results indicate aspects of caring for a child with EB that may be under-recognized by healthcare professionals (HCPs) and allied caretakers. Examples of this was extensive home care, learning skin care through trial-and-error, tension between illness-demands and the child's psychological needs, and parents being gatekeepers of their child's well-being.

Conclusions: Caring for a child with EB may imply practical and emotionally demanding tasks for the parents, and possible unmet healthcare needs. It is important that HCPs recognize and understand the potential burden of extensive home care these parents experience as part of providing for their child with EB and the family.

Background: The aim of our multicenter study was to investigate the implementation of the European Fabry guidelines on therapeutic recommendations in female patients with Fabry disease (FD) and to analyze the impact of enzyme replacement therapy (ERT) in treated and untreated females.

Results: Data from 3 consecutive visits of 159 female FD patients from 6 Fabry centers were retrospectively analyzed. According to their treatment, patients were separated in 3 groups (untreated, n = 71; newly ERT-treated, n = 47; long-term ERT-treated, n = 41). Clinical presentation and laboratory data, including plasma globotriaosylsphingosine (lyso-Gb₃) levels were assessed. The observation time ranged from 49 to 62 months. ∼90% of female patients treated with ERT presented with at least one organ manifestation justifying treatment according to current European guidelines. Untreated females showed a less severe disease load with less FD-typical organ damage. All groups presented with a stable cardiac status (all p > 0.05) over time. ERT-treated females presented with a slight yearly loss of estimated glomerular filtration (eGFR) over time (both p < 0.05), which was comparable to the natural decline for this age. Plasma lyso-Gb₃ levels were higher in ERT-treated females and decreased by 0.95 [-4.44 to 4.08] ng/ml/year (p = 0.0002) in those who were newly ERT-treated.

Conclusions: Severely affected females with FD who were treated with ERT, and less severely affected untreated females, showed a broadly stable disease course over 5 years. The treatment decisions were largely based on the European guidelines for FD. In untreated females, it is crucial to explore if organ involvement is FD-related in order to make the correct treatment decision.

Objective: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by proximal muscle weakness and atrophy. The increasing availability of disease-modifying therapies has prompted the development of biomarkers to facilitate clinical assessments. We explored the association between disease severity and serum creatinine (Crn) levels in SMA patients undergoing up to two years of treatment with nusinersen.

Methods: We measured serum Crn levels and assessed function performance using the Hammersmith Functional Motor Scale-Expanded (HFMSE), Medical Research Council Scale (MRC), 6-Minute Walk Test (6MWT), ulnar Compound Muscle Action Potential (CMAP), and forced vital capacity (FVC) in a cohort comprising 28 adolescent and adult patients with SMA. The association between Crn and disease severity was investigated through partial rank correlation analysis and linear mixed models while accounting for age, gender, and BMI. Linear models were employed to predict functional performance.

Results: 28 SMA patients and 28 gender- and age-matched healthy controls (HCs) were included, resulting in a dataset of 185 visits. Compared to HCs, SMA patients exhibited significantly lower Crn values ​​(67.4 ± 14 vs. 23.7 ± 14.8 umol/L, p<0.0001). After adjusting for age, sex, and BMI, Crn showed positive correlations with the HFMSE (p<0.0001, r = 0.884), MRC (p<0.0001, r = 0.827), FVC (p = 0.002, r = 0.730), and ulnar CMAP (p<0.0001, r = 0.807). Patients with SMN2 copy number ≥ 4 had nearly twice as high Crn levels as those with SMN2 copy number < 4 (34.1 ± 3.75 vs. 17.2 ± 2.52 umol/L, p = 0.00145). Ambulant SMA patients had more than double the Crn levels compared to non-ambulant ones (32 ± 2.33 vs. 12.9 ± 2.38 umol/L, p<0.0001). Furthermore, Crn explained that up to 83.5% of the variance in functional performance measured by HFMSE, MRC, and 6MWT was significantly higher than that of traditional biomarkers.

Conclusions: These findings suggest that Crn may be a potential biomarker for assessing disease severity in adolescents and adults with SMA, demonstrating its promise in clinical applications.

Background: GTPBP3 catalyzes τm⁵(s²) U biosynthesis at the 34th wobble position of mitochondrial tRNAs, the hypomodification of τm⁵U leads to mitochondrial disease. While twenty-three variants of GTPBP3 have been reported worldwide, the genetic landscape in China remains uncertain.

Methods: By using whole-exome sequencing, the candidate individuals carrying GTPBP3 variants were screened and identified. Pathogenicity analysis of variants was biochemically verified by patients-derived immortalized lymphocytes and cell models.

Results: Through whole-exome sequencing, thirteen variants associated with GTPBP3 were identified in nine Chinese pedigrees, with eight of these variants being newly reported. Affected individuals displayed classic neurologic phenotypes and heart complications including developmental delay, seizures, hypotonia, exercise intolerance, and hypertrophic cardiomyopathy. Additionally, they displayed new symptoms such as eye problems like strabismus and heart issues related to valve function. Studies conducted on patient-derived cells provided evidence of reduced levels of GTPBP3 and impairment in mitochondrial energetic biogenesis. Re-expressing GTPBP3 variants in knockout cell lines further defined the pathogenicity of the novel variants. Analysis of the genetic spectrum in the Chinese population highlighted a concentration in exons 4 and 6, with c.689A > C being the prominent hotspot.

Conclusion: Our findings emphasize the extensive clinical and genetic implications of GTPBP3-related mitochondrial disorders, particularly within the Chinese population, but further investigations are needed to explore the phenotype-genotype correlation.

Background and objectives: Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is a maternally inherited mitochondrial disorder that mostly affects the central nervous system and skeletal muscle. This study provides a comprehensive summary of the clinical symptoms, multisystemic pathogenesis, and genetic characteristics of MELAS syndrome. The aim was to improve comprehension of clinical practice and gain a deeper understanding of the latest pathophysiological theories.

Methods: The present investigation involved a cohort of patients diagnosed with MELAS at Nanjing Drum Tower Hospital between January 2014 and December 2022. Multisystem symptoms, magnetic resonance imaging/spectroscopy (MRI/MRS), muscle biopsy, and mitochondrial DNA (mtDNA) data were summarized and subsequently analysed.

Results: This retrospective study included a cohort of 29 MELAS patients who predominantly presented symptoms such as stroke-like episodes, proximal muscle weakness, and exercise intolerance. MRI scans revealed very small infarcts beneath the deep cortex during stroke-like episodes, indicating nonvascular brain damage. Pathology analyses of the brain also showed neuronal degeneration and glial cell proliferation in the cerebral parenchyma. Proton magnetic resonance spectroscopy (¹H-MRS) analysis revealed an increase in the lactate peak and a reduction in the N-acetylaspartate (NAA) level. Similarly, the phosphorus magnetic resonance spectroscopy (³¹P-MRS) analysis revealed an abnormal ratio of inorganic phosphate (Pi) to phosphocreatine (PCr). Muscle biopsy revealed the presence of ragged red fibres (RRFs) and cytochrome c oxidase (COX) enzyme-defective cells. These abnormalities indicate structural abnormalities in the mitochondria and deficiencies in oxidative phosphorylation, respectively. In addition to the common m.3243A > G variant, other prevalent variants, including m.5628 T > C, m.6352-13952del, and a 9-bp small deletion combined with m.3243A > G, exist.

Conclusions: MELAS is a rare mitochondrial syndrome characterized by clinical heterogeneity and genetic heteroplasmy. Abnormalities in mitochondrial metabolic function and impairments in enzyme activity are the pathogenic processes underlying MELAS. Mitochondrial vasculopathy and mitochondrial neuropathy may provide a partial explanation for the unique aetiology of stroke-like episodes.

Background: The combination of high prices and uncertain effectiveness is a growing challenge in the field of orphan medicines, hampering health technology assessments. Hence, new methods for establishing price benchmarks might be necessary to support reimbursement negotiations. In this study, we applied several pricing models containing cost-based elements to the case of lumasiran for treating primary hyperoxaluria type 1.

Methods: Price ranges were calculated by estimating minimum and maximum scenarios for four pricing models: Novel Cancer Pricing Model (NCP-model), AIM Model for Innovative Medicines (AIM-model), Discounted Cash Flow model (DCF-model), and the Real-Option Rate Of Return model (ROROR-model). Data was gathered from disease registries, scientific literature, Security and Exchange Committee filings, and expert opinion. A sensitivity analysis was performed to assess the parameters with the largest influence.

Results: Outcomes resulting from the NCP-model ranged between €87,000 and €224,000 per patient per year, between €33,000 and €340,000 for the AIM-model, between €182,000 and €748,000 for the DCF-model, and between €81,000 and €273,000 for the ROROR-model.

Conclusion: Outcomes of the four pricing models show wide and heterogeneous price ranges. The DCF-model might be most compatible with the case of lumasiran, due to inclusion of parameters for prevalence, incidence, prescription restrictions and cost of capital. The minimum DCF price could serve as a starting point for pricing and reimbursement negotiations. Uncertainties can be solved by more transparency on input variables.

Mitochondrial transcription factor A (TFAM) deficiency may cause mtDNA depletion syndrome, which manifests as neonatal liver failure or primary ovarian insufficiency, hearing loss, seizures, and intellectual disability. Treatment focusing on symptomatic management, and the clinical prognosis remains poor. Here, we describe a novel case of TFAM mutation presenting with progressive neonatal cholestasis, hypoglycemia and abnormal amino acid profiling. The patient progressed to liver failure at 6 months of age but did not exhibit neurological involvement. No morphologic abnormalities were observed in muscle biopsy, while mtDNA copy number was reduced in comparison to age- and tissue-matched controls. After liver transplantation, liver biochemistries and blood amino acid profiling normalized three weeks later. Moreover, the boy was doing well post-transplant without any clinical concerns, and his development and neurological examination remain normal 33 months after liver transplantation. Our report suggests that liver transplantation appears to have a favorable profile in such patients.

Background: Neuromyelitis Optica Spectrum Disorders (NMOSD) comprise a group of autoimmune-mediated, inflammatory, demyelinating central nervous system diseases caused by aquaporin-4 (AQP4) IgG autoantibodies. Efgartigimod is a human IgG Fc fragment that reduces antibody titers by targeting the neonatal Fc receptor (FcRn). This study documents the efficacy of efgartigimod combined with intravenous methylprednisolone (IVMP) in the acute phase of NMOSD.

Methods: In this retrospective study, the medical records of NMOSD patients with acute attack who received efgartigimod plus IVMP or IVMP were reviewed. Treatment efficacy was assessed by the Expanded Disability Scale Score (EDSS) before and one month after treatment. Any side effects that occurred during the treatment period were recorded.

Results: This study was performed on 11 patients (efgartigimod plus IVMP group [n = 4] and IVMP group [n = 7]). Efgartigimod plus IVMP was effective and had a satisfactory safety profile. EDSS was reduced by 0.5 ± 0.32 compared with the IVMP group (0.27 ± 0.02). Immunoglobulin was decreased in three patients, and the immunoglobulin G (IgG) levels gradually increased approximately 8 weeks after the last administration. Hyperlipidemia and elevated white blood cell count were common side effects. No infections or deaths occurred.

Conclusions: Efgartigimod plus IVMP treatment is safe and well-tolerated in patients with acute-phase NMOSD.