Introduction: The SCL16A2 gene encodes the thyroid hormone (TH) transporter MCT8. Pathogenic variants result in a reduced TH uptake into the CNS despite high serum T3 concentrations. Patients suffer from severe neurodevelopmental delay and require multidisciplinary care. Since a first compassionate use study in 2008, the development of therapies has recently gained momentum. Treatment strategies range from symptom-based approaches, supplementation with TH or TH-analogs, to gene therapy. All these studies have mainly used surrogate endpoints and clinical outcomes. However, the EMA and FDA strongly encourage researchers to involve patients and their advocacy groups in the design of clinical trials. This should strengthen the patients’ perspective and identify clinical endpoints that are clinically relevant to their daily life. Methods: We involved patient families to define patient-relevant outcomes for MCT8 deficiency. In close collaboration with patient families, we designed a questionnaire asking for their five most preferred therapeutic goals, which, if achieved at least, make a difference in their lives. In addition, we performed a systematic review according to Cochrane recommendations of the published treatment trials. Results: We obtained results from 15 families with completed questionnaires from 14 mothers and 8 fathers. Improvement in development, especially in gross motor skills, was most important to the parents. 59% wished for head control and 50% for sitting ability. Another 36% wished for weight gain, 32% for improvement of expressive language skills, and 18% for a reduction of dystonia/spasticity, less dysphagia, and reflux. Paraclinical aspects were least important (5– 9%). In a treatment trial (n=46) and compassionate use cases (n=83), the results were mainly inconclusive, partly due to a lack of predefined patient-centered clinical endpoints. Discussion: We recommend that future trials should define a relevant improvement in “development” and/or other patient-relevant outcomes compared to natural history as treatment goals.

BACKGROUND AND PURPOSE: While classic brain MR imaging features of Alexander disease have been well-documented, lesional patterns can overlap with other leukodystrophies, especially in the early stages of the disease or in milder phenotypes. We aimed to assess the utility of a new neuroimaging sign to help increase the diagnostic specificity of Alexander disease. MATERIALS AND METHODS: A peculiar bilateral symmetric hyperintense signal on T2-weighted images affecting the medulla oblongata was identified in an index patient with type I Alexander disease. Subsequently, 5 observers performed a systematic MR imaging review for this pattern by examining 55 subjects with Alexander disease and 74 subjects with other leukodystrophies. Interobserver agreement was assessed by the κ index. Sensitivity, specificity, and receiver operating characteristic curves were determined. RESULTS: The identified pattern was present in 87% of subjects with Alexander disease and 14% of those without Alexander disease leukodystrophy (P < .001), 3 with vanishing white matter, 4 with adult polyglucosan body disease, and 3 others. It was found equally in both type I and type II Alexander disease (28/32, 88% versus 18/21, 86%; P = .851) and in subjects with unusual disease features (2/2). Sensitivity (87.3%; 95% CI, 76.0%–93.7%), specificity (86.5%; 95% CI, 76.9%–92.5%), and interobserver agreement (κ index = 0.82) were high. CONCLUSIONS: The identified pattern in the medulla oblongata, called the chipmunk sign due to its resemblance to the face of this rodent, is extremely common in subjects with Alexander disease and represents a diagnostic tool that can aid in early diagnosis, especially in subjects with otherwise atypical MR imaging findings and/or clinical features.

X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder, caused by mutations in the ABCD1 gene. Early diagnosis is critical to manage adrenal insufficiency and cerebral forms of the disease. Since 2021, a pilot newborn screening (NBS) program for X-ALD has been launched in Lombardy, Italy. From September 2021 to June 2025, 138,116 newborns (≥37 weeks’ gestational age) were screened for elevated C26:0-lysophosphatidylcholine (C26:0-LPC) levels using a two-tier algorithm. Genetic testing was performed in non-negative cases. Males found to be ABCD1 variant carriers were enrolled in multidisciplinary follow-up, including neurological, endocrinological, and nutritional assessments. Eleven individuals (six males, five females) carried pathogenic or likely pathogenic ABCD1 variants. Three males were diagnosed with adrenal insufficiency and started hydrocortisone therapy between 1 and 2 years of age. Growth parameters were within normal range overall, but two children showed signs of stunting associated with poor dietary compliance. Additionally, three patients were diagnosed with Zellweger spectrum disorders (ZSDs). No patients affected with Aicardi-Goutières Syndrome were identified. Newborn screening for X-ALD in Italy is feasible and enables early detection and intervention. Biochemical markers and genetic analysis are reliable tools for identifying affected males and female carriers. Multidisciplinary management is essential to address medical and psychosocial challenges during follow-up.

Alexander disease (AxD) is a rare and progressive leukodystrophy caused by variants in the Glial Fibrillary Acidic Protein (GFAP) gene. AxD presents as Type I and Type II, based on clinical and neuroradiological features. However, Type I patients variable disease progression has led to sub-classify them into subtypes Ia-Ib-Ic-Id. Our study investigated genotype-phenotype correlations in Type I AxD across these subtypes. A cohort of 74 genetically confirmed Type I AxD patients was analysed, with variants classified according to the clinical subtypes Ia, Ib, Ic, and Id. Genotypic-phenotypic correlations were explored both across all subtype groups and in stratified analyses based on patients' ability to achieve independent ambulation versus those who never acquired this milestone. To investigate the functional consequences of a representative variant, in vitro assays were performed. Selected mutant GFAP protein was expressed and their ability to assemble into intermediate filament networks was assessed. The study revealed a progressive decrease in GFAP allelic heterogeneity across disease subtypes from Ia to Id. Additionally, GFAP pathogenic variants in exon 1 were more frequent in milder forms, whereas mutations in exon 4 were predominantly observed in severe phenotypes. In addition, changes at p.R239 and p.R79 residues showed an opposite trend, with variants affecting p.R239 never detected in Id subtype, while variants affecting p.R79 never detected in Ia. Specific aminoacidic changes at the p.R79 residue were able to stratify patients based on ability to acquire independent ambulation or not. Furthermore, the distribution of Combined Annotation Dependent Depletion (CADD) scores showed an inverse correlation with the acquisition of autonomous ambulation. These results suggest that specific GFAP variants could be potential predictors for disease progression in Type I AxD, supporting patients' subclassification and underscoring the importance of considering both genetic and clinical factors in AxD management, particularly as therapeutic interventions are being developed.

Aicardi-Goutières Syndrome (AGS) is a genetic type 1 interferonopathy that causes white matter abnormalities and intracranial calcifications, resulting in varying degrees of neurologic impairment and systemic manifestations. Novel disease-modifying therapies for AGS are forthcoming. The 2022 Food and Drug Administration guidance, "Patient-Focused Drug Development" (PFDD), emphasizes the importance of including patients' voices early in the design of clinical trials. This represents an urgent unmet need in rare disease research. In this study, we propose and pilot a new methodology to identify patient-centered Concepts of Interest (COIs) and suitable Clinical Outcome Assessments (COAs) for clinical trials. The study was performed under the Myelin Disease Biorepository Project within the Global Leukodystrophy Initiative Clinical Trial Network. A sequential multicomponent approach, piloted in AGS, was designed to (i) identify COIs, (ii) select COAs capable of measuring the COIs through expert consensus, and (iii) assess the feasibility of COA application. Experts were identified based on relevant scientific publications and expertise in AGS (disease experts for COI) and/or their application of relevant COAs (outcome experts for COA). Expert consensus was achieved using the modified eDelphi approach for COIs, expertise-specific multi-panel focus group discussions, and pre-and post-surveys for COA selection. Consensus was defined as ≥70% agreement among the experts. This was followed by a virtual stakeholder discussion with patients and/or patient representatives to assess the feasibility of the COA application in the context of a clinical trial. Based on the health priorities identified by patient caregivers, the proposed approach revealed a set of fit-for-purpose COIs across the motor, adaptive behavior, and neurologic functional domains. All experts acknowledged the significance of each caregiver-identified priority but expressed differing opinions on the likelihood of observing changes in the functional domain within a 6- to 12-month timeframe. Following this, a consensus-building approach for COA selection for each identified COI resulted in a paired COI-COA panel applicable to future AGS clinical trials. Finally, the discussion on the feasibility of application of the selected COAs with the patients and/or patient representatives elicited critical information to design a patient-centered prospective COA protocol, applicable to clinical trials and natural history studies. The proposed approach marks the first step toward a patient-centered clinical trial design for rare diseases. It establishes a paired COI-COA panel, as well as informs the design of a patient-centered prospective COA protocol for upcoming AGS clinical trials and natural history studies. Additionally, the identified COA panel facilitates the creation of a multicomponent endpoint for clinical trials, which is especially crucial in phenotypically diverse disorders like AGS. This approach is widely applicable across leukodystrophies and rare diseases.