Transplantation is an effective therapeutic option to improve quality of life in patients with severe methylmalonic acidemia (MMA). However, data regarding neurological complications following transplantation remain limited. A retrospective, single-center study was conducted at Necker Hospital (France), including MMA patients who underwent kidney (KT), liver (LT), or liver-kidney transplantation (LKT) between 2007 and 2022. Our aim was to evaluate acute neurological complications occurring after transplantation, focusing on clinical features, laboratory parameters and neuroimaging. Sensorineural complications were also assessed. Thirty-five patients were included, 21 had undergone LKT, 10 LT and 4 KT. The median age at transplantation was 10.1 years, with a median follow-up of 5 years. Tacrolimus was used in 91% of patients. Acute neurological complications likely related to MMA occurred in 17% of patients. They include Leigh syndrome with identifiable triggers, observed in 4 patients (2 early and 2 late-post-transplantation), leading to one early- and one late-onset death. Stroke-like episodes occurred in 2 patients. Non-epileptic myoclonus, likely related to calcineurin inhibitor (CNI), were reported in 31% of patients. Pre-transplant brain MRI showed nonspecific abnormalities in 31% of patients and remained stable afterwards. Post-transplant ophthalmological data available for 17 patients showed 3 optic atrophies. No acute vision or hearing loss was reported. Although transplantation improves metabolic control in MMA, acute neurological complications can still occur following a triggering event, even years after transplantation. The risk may arise from sensitivity to CNI-induced neurotoxicity. Pre- and post-transplant neuroimaging, emergency metabolic protocols, and tailored immunosuppression are essential for long-term management.

Treatment for patients with bilateral adrenal tumours and cortisol excess is not standardised and poses a therapeutic dilemma. Untreated cortisol excess is associated with cardiometabolic morbidity and mortality, but bilateral adrenalectomy causes adrenal insufficiency and possibly life-threatening adrenal crises. Data on cardiovascular outcomes by treatment modality are scarce. In this study we aimed to evaluate mid-term and long-term clinical and biochemical outcomes in patients with bilateral adrenal tumours and cortisol excess by treatment strategy and diagnosis. This retrospective, international cohort study (in 30 centres across 10 countries in Europe plus Singapore and the USA) included patients with bilateral adrenal tumours of 10 mm or larger, post-dexamethasone serum cortisol concentration of 50 nmol/L or higher, and at least 36 months of follow-up, with data collection beween Feb 2, 2024, and Jan 31, 2025. Patients were excluded if they had adrenocorticotropin hormone (ACTH)-dependent cortisol excess, ACTH-dependent nodular adrenal hyperplasia, partial glucocorticoid resistance syndrome, a diagnosis inconsistent with benign adrenocortical lesions, or received systemic oral or intravenous glucocorticoids other than replacement therapy following adrenalectomy. Primary endpoints were all-cause mortality and clinical and biochemical remission rates. Secondary endpoints were the incidence of cardiovascular events, prevalence of vascular and metabolic comorbidities, and incidence of adrenal crises. Of 629 patients who were diagnosed between Jan 1, 2000, and Jan 31, 2022, 105 (17%) had Cushing's syndrome and 524 (83%) had mild autonomous cortisol secretion (MACS), median age was 62 years (IQR 54·0-68·0), and 426 (68%) were female. 85 (81%) of 105 patients with Cushing's syndrome underwent surgery, and 384 (73%) of 524 patients with MACS received non-specific symptomatic treatment (ie, never underwent adrenalectomy or received steroidogenesis inhibitors). Over a median follow-up of 6·8 years, biochemical remission was achieved in 46 (45%) of 102 patients with Cushing's syndrome and in 67 (13%) of 517 patients with MACS. In both groups, 7% of patients died (Cushing's syndrome: seven of 105; MACS: 38 of 524) and 12% (13 of 105) of patients with Cushing's syndrome and 16% (82 of 524) of those with MACS had at least one cardiovascular event, without substantial differences across treatments. Smoking emerged as key modifiable mortality and cardiovascular risk factor in all patients, and in patients with MACS who only received non-specific symptomatic therapy, post-dexamethasone cortisol was also associated with increased mortality. Bilateral adrenalectomy led to full biochemical remission, few non-fatal adrenal crises, and improved arterial hypertension. Unilateral adrenalectomy and steroidogenesis inhibitors yielded heterogeneous biochemical outcomes and no substantial comorbidity improvement. Non-specific symptomatic treatment in MACS was associated with worsening of all investigated comorbidities. Although mortality and cardiovascular event rates were similar across treatments, surgery led to better biochemical control and more favourable comorbidity outcomes. None.

The Hunter Outcome Survey (HOS) collected global, real-world data on the natural history of mucopolysaccharidosis II and its treatment with intravenous idursulfase. For eligible patients, home therapy offers a convenient alternative to in-clinic therapy. Using data in HOS as of January 2023, we provide an updated assessment of the safety/tolerability profile of home therapy with idursulfase. The analysis population comprised 333 patients who had received at least one home infusion and 708 patients who had never received home therapy. Median (10th percentile [P10], 90th percentile [P90]) age at home therapy start was 8.9 (2.9, 21.1) years. Median (P10, P90) ages at latest visit were 15.5 (7.7, 29.3) years in the home therapy group and 13.9 (5.2, 29.0) years in the no home therapy group. Patients received a median (P10, P90) of 6.0 (0.8, 12.0) years of home infusions after 1.8 (0.3, 8.7) years of in-clinic therapy, and these timings varied by geographic region. The infusion-related reaction (IRR) rate was 0.11/patient-year during home therapy, 0.13/patient-year for the in-clinic period for the same patients (first 6 months excluded), and 0.05/patient-year for patients who never received home therapy (first 6 months excluded). More than 60% of IRRs were categorized as mild. The adverse event (AE) rate was lower during home therapy (0.59 AEs/patient-year) than during the in-clinic period for the same patients (0.86 AEs/patient-year). Among patients who never received home therapy, the rate was 0.60 AEs/patient-year. Deaths occurred at a rate of 2.17 deaths/100 patient-years of home therapy and 3.60 deaths/100 patient-years among patients never treated with home therapy. No deaths were deemed related to treatment. The rate of missed infusions was 0.52/year during the home therapy period compared with 1.42/year during the in-clinic period for the same patients and 0.57/year for patients who never received home therapy. Our data indicate a similar safety/tolerability profile for intravenous idursulfase administered at home and in clinic in patients with mucopolysaccharidosis II.

This narrative review explores the therapeutic potential of repurposing medications originally developed or approved for osteoporosis to treat non-osteoporotic conditions. Given their pharmacologic profiles and safety data, these agents offer promising therapeutic alternatives in both rare and common diseases with unmet clinical needs. Evidence from preclinical models, observational data, and randomised trials supports the repositioning of several osteoporosis drugs. Cyclic etidronate has shown efficacy in halting arterial calcification progression in pseudoxanthoma elasticum. Pamidronate has demonstrated symptom improvement in adult chronic nonbacterial osteitis. Neridronate is approved only in Italy for complex regional pain syndrome type I. Denosumab has shown therapeutic effects in Langerhans cell histiocytosis and has structural benefits in erosive hand osteoarthritis and rheumatoid arthritis. Parathyroid hormone analogues (rhPTH [1-84] and teriparatide) improve calcium-phosphate homeostasis in chronic and genetic hypoparathyroidism. Calcilytics, though originally discontinued for osteoporosis, show emerging promise in autosomal dominant hypoparathyroidism. In contrast, zoledronic acid has not demonstrated consistent clinical benefit in knee osteoarthritis. Strontium ranelate, despite showing structure-modifying effects in osteoarthritis, is no longer marketed due to safety concerns. Alendronate and denosumab in fibrous dysplasia yielded mixed results, with concerns about rebound effects after denosumab withdrawal. Repurposing osteoporosis medications represents a cost-effective, timely strategy to expand treatment options across diverse clinical indications. While promising outcomes have been demonstrated-particularly in rare diseases-rigorous, indication-specific clinical trials are essential to confirm efficacy, safety, and long-term outcomes. The accumulated pharmacologic and clinical experience with these agents offers a strong foundation for their continued exploration beyond osteoporosis.

Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder. This study aimed to analyze the genotype distribution of FCS-causing genes in the United Kingdom. Data were anonymously collated from 2 genetic testing laboratories providing national genetic diagnosis services for severe hypertriglyceridemia in the United Kingdom. As of December 2023, 880 individuals underwent genetic testing for FCS. The mean (SD) age at the time of genetic testing was 42.5 (15.3) years. After genotyping, 12.9% of the individuals (n = 114) received a genetic diagnosis of FCS. The detection rate of variant-positive multifactorial chylomicronemia syndrome, ie, heterozygous for pathogenic/likely pathogenic (P/LP) variants in 1 of the 5 canonical genes was 11.4% (n = 100).Among 114 genetically proven FCS individuals, 52.6% (n = 60) had biallelic P/LP LPL variants (ie, LPL-FCS), 45.6% (n = 52) had biallelic non-LPL P/LP variants (ie, non-LPL-FCS) and 1.7% (n = 2) individuals were digenic. Among non-LPL-FCS (n = 52), the most common gene implicated was GPIHBP1 (42.3%, n = 22), followed by APOA5 (32.7%, n = 17), LMF1 (13.5%, n = 7) and APOC2 (11.5%, n = 6). Most variant-positive multifactorial chylomicronemia syndrome harbored P/LP variants in LPL (61%) or APOA5 (37%).The geographical distribution of FCS demonstrated regional variability, where the Northwest of England had the highest number of FCS cases per million population. Individuals of European geographic ancestry predominantly had LPL-FCS (60.9%); however, genotype was more diverse in individuals of non-European origin (LPL 47.1%, GPIHBP1 30.9%, APOA5 8.8%, LMF1 7.4%, and APOC2 4.4%). Variants in specific causal genes, GPIHBP1 and LMF1, were predominantly observed in non-European FCS individuals. The genetic architecture of FCS in the United Kingdom is complex, with a substantial proportion affected by non-LPL FCS-causing genes. It also displays a significant regional and ethnic variations.