Immunotherapy and Radiotherapy for Older Patients with Locally Advanced Non-Metastatic Non-Small-Cell Lung Cancer Who Are Not Candidates for or Decline Surgery and Chemotherapy: A Practical Proposal by the International Geriatric Radiotherapy Group.

The standard of care for locally advanced non-small-cell lung cancer (NSCLC) is either surgery combined with chemotherapy pre- or postoperatively or concurrent chemotherapy and radiotherapy. However, older and frail patients may not be candidates for surgery and chemotherapy due to the high mortality risk and are frequently referred to radiotherapy alone, which is better tolerated but carries a high risk of disease recurrence. Recently, immunotherapy with immune checkpoint inhibitors (ICIs) may induce a high response rate among cancer patients with positive programmed death ligand 1 (PD-L1) expression. Immunotherapy is also well tolerated among older patients. Laboratory and clinical studies have reported synergy between radiotherapy and ICI. The combination of ICI and radiotherapy may improve local control and survival for NSCLC patients who are not candidates for surgery and chemotherapy or decline these two modalities. The International Geriatric Radiotherapy Group proposes a protocol combining radiotherapy and immunotherapy based on the presence or absence of PD-L1 to optimize the survival of those patients.

A Reversible Etiology of Progressive Motor Decline in a Previously Healthy Child.

We describe the clinical presentation and evaluation of a 10-year-old boy who presented to our medical center with years of progressive proximal muscle weakness, muscle atrophy, and weight loss. In addition to a myopathic phenotype, he was found to have tachycardia, tremor, and learning difficulties. Electromyography revealed chronic myopathic changes and laboratory screening was notable for undetectable thyroid stimulating hormone. Follow-up testing revealed elevated thyroid peroxidase antibodies and thyroid stimulating immunoglobulins. Ultrasound examination revealed an enlarged heterogeneous thyroid gland. Four weeks after treatment with atenolol and methimazole, his strength and cognition began to improve. This case highlights the importance of evaluating for potentially reversible toxic-metabolic etiologies in children presenting with any progressive neurologic symptoms.

Do behavioral drivers matter for healthcare decision-making during crises? A study of low-income women in El Salvador during the COVID-19 pandemic.

Understanding health-seeking behaviors and their drivers is key for governments to manage health policies. A growing body of research explores the role of cognitive biases and heuristics in health and care-seeking behaviors, but little is known about how a context of heightened anxiety and uncertainty might influence these behavioral drivers. This study analyzes the association between four behavioral predictors-internal locus of control, impatience, optimism bias, and aspirations-and healthcare decisions among low-income women in El Salvador, controlling for other factors. We find positive associations between internal locus of control and preventive health behaviors during the COVID-19 pandemic. For instance, a one standard deviation increase in locus of control is associated with a 10% increase in an index measuring the use of masks, distancing, hand washing, and vaccination. Locus of control was also associated with women's use of preventive health services (one standard deviation improves the likelihood of having a hypertension test in the last six months by 5.8 percentage points). In a sub-sample of mothers, we find significant relationships between the four behavioral drivers and the decisions the mothers make for their children. However, we find these associations are less robust compared to the decisions they make for themselves. Some associations were stronger during the pandemic, suggesting that feelings of uncertainty and stress could amplify behavioral drivers' influence on health-related behaviors. This novel finding is relevant for designing policy responses for future shocks. JEL CODES: I12, D10, D91, I30.

Immunotherapy and stereotactic body radiotherapy for older patients with non-metastatic renal cancer unfit for surgery or decline nephrectomy: practical proposal by the International Geriatric Radiotherapy Group.

The standard of care for non-metastatic renal cancer is surgical resection followed by adjuvant therapy for those at high risk for recurrences. However, for older patients, surgery may not be an option due to the high risk of complications which may result in death. In the past renal cancer was considered to be radio-resistant, and required a higher dose of radiation leading to excessive complications secondary to damage of the normal organs surrounding the cancer. Advances in radiotherapy technique such as stereotactic body radiotherapy (SBRT) has led to the delivery of a tumoricidal dose of radiation with minimal damage to the normal tissue. Excellent local control and survival have been reported for selective patients with small tumors following SBRT. However, for patients with poor prognostic factors such as large tumor size and aggressive histology, there was a higher rate of loco-regional recurrences and distant metastases. Those tumors frequently carry program death ligand 1 (PD-L1) which makes them an ideal target for immunotherapy with check point inhibitors (CPI). Given the synergy between radiotherapy and immunotherapy, we propose an algorithm combining CPI and SBRT for older patients with non-metastatic renal cancer who are not candidates for surgical resection or decline nephrectomy.

Combined Ultrahypofractionated Whole-Breast Irradiation and IORT-Boost: A Safety and Feasibility Analysis.

BACKGROUND: The current standard of local treatment for patients with localized breast cancer (BC) includes whole breast irradiation (WBI) after breast-conserving surgery (BCS). Ultrahypofractionated WBI schemes (1-week treatment) were shown not to be inferior to the standard WBI. Tumor bed boost using photon intraoperative radiotherapy (IORT) is safe and feasible in combination with standard WBI. The aim of the present study is to assess, for the first time, the feasibility and safety of combining photon IORT with ultrahypofractionated WBI. METHODS: Patients diagnosed with low-risk early BC candidates for BCS were included in this prospective study. IORT was administered at a dose of 20 Gy to the surface's applicator, and WBI was administered 3-5 weeks after surgery at a total dose of 26 Gy in five consecutive days. RESULTS: From July 2020 to December 2022, seventy-two patients diagnosed with low-risk early BC and treated in our institution were included in this prospective study. All patients completed the proposed treatment, and no severe acute or late grade 3 toxicity was observed 3 and 12 months after WBI, respectively. CONCLUSIONS: Our results confirm for the first time that the combination of ultrafractionation WBI and photon-IORT after BCS is a feasible and safe option in patients with early BC.

Ten-Year Results of Accelerated Partial-Breast Irradiation with Interstitial Multicatheter Brachytherapy after Breast-Conserving Surgery for Low-Risk Early Breast Cancer.

Patients with an early carcinoma of the breast are commonly treated by breast-conserving surgery (BCS) and postoperative radiotherapy. Partial-breast irradiation has gained acceptance in the last few years. Between December 2008 and December 2017, 182 low-risk breast cancer patients treated by BCS in the four university hospitals of the province of Las Palmas and treated with APBI using interstitial multicatheter brachytherapy were included in this study. After a mean follow-up for survivors of 10 years, the treatment was shown to be safe, as no severe acute/late toxicity (grade ≥ 3) was observed. The 10-year IBTR was 1.7% (95%CI: 0.7-2.7%), and the cause-specific survival was 94.9% (95%CI: 93.2-96.6%). We suggest that multicatheter brachytherapy after BCS is safe and effective in early breast cancer patients.

A methodology to simulate peak water demand for water supply systems using semi-direct methods: A case study for a residential building in Mexico.

Historically, approaches for determining peak water demand in buildings have been based on probabilistic methods. Extensive research has shown that these methods lack accuracy because of the human factor in the probability of use. Inaccuracy in the calculation of peak water demand is the main cause of oversized water supply systems in buildings. This has led to unfavorable effects such as: 1) increasing the building carbon footprint due to the use of more construction materials, and 2) engendering health hazards due to the stagnation of water causing microbial growing. This paper presents a step-by-step methodology that serves to calculate the peak water demand by simulating the use of plumbing fixtures based on data obtained from standardized flowrate. With the implementation of the methodology, the peak water demand estimated was 2.6 times lower in comparison to traditional methods. The main conclusion drawn from the research is the potential of the methodology to easily simulated peak water demand in residential buildings in the short term. Thus, it reveals a hotspot for peak water demand calculation and can serve as routes for future research.

Disruption Of Non-COVID-19 Health Care In Latin America During The Pandemic: Effects On Health, Lessons For Policy.

COVID-19 had severe direct and indirect effects on health and well-being in Latin America. To understand the extent to which disruptions among non-COVID-19-related health services affected population health, we used administrative data from the period 2015-21 to examine public hospital discharges and mortality for conditions amenable to health care in four Latin American countries: Brazil, Ecuador, Mexico, and Peru. Between March 2020 and December 2021, hospitalization rates for these conditions declined by 28 percent and mortality rates increased by 15 percent relative to prepandemic years. Noncommunicable diseases accounted for 89 percent of this rise in mortality. The poorest states in each country experienced relatively larger increases in mortality. Our results, which focus on the health effects of service disruption, suggest that maintaining health care services in this region during the pandemic could have avoided at least 96,000 deaths. Policies should focus on maintaining essential health care services during emergencies, particularly for patients with noncommunicable diseases, and on minimizing negative consequences by ensuring coordinated and continuous care; leveraging alternative modalities of care, such as telemedicine; broadening the role of nonphysician health care workers; and expanding options for medication delivery.

[Efficacy and safety of atorvastatin in major cardiovascular events: Meta-analysis]. / Eficacia y seguridad de la atorvastatina en eventos cardiovasculares mayores: metaanálisis.

Introduction: Atorvastatin has been used in the management of dyslipidemia and little is known about the efficacy and safety of high-dose atorvastatin administration for secondary prevention of Major Cardiovascular Events (MACE). Objective: To evaluate the impact of high-dose atorvastatin on secondary prevention of MACE and adverse events. Material and methods: A systematic review and meta-analysis of Pubmed, Embase, Bireme and Cochrane Library Plus databases was performed, with a time scope from 1990 to July 2022. Six randomized clinical trials were included with a total of 29,333 patients who were treated with 80 mg, 10 mg or placebo doses of Atorvastatin where the main outcomes evaluated were Major Cardiovascular Events (MACE), mortality and treatment safety. Results: In the comparative study between the use of Atorvastatin 80 mg and other therapies, a relative risk (RR) of 0.8 (95%CI 0.69-0.92) was found, representing a 20% reduction in risk (RRR) and a number needed to treat (NNT) of 30-55. In the analysis of adverse effects, an RR of 2.37 (95% CI 0.86-6.53) and a number needed to harm (NNH) of 14-19 were observed. The use of 80 mg atorvastatin is associated with similar adverse events at lower doses. Conclusions: The use of atorvastatin 80 mg is effective in the secondary prevention of Major Cardiovascular Event (MACE). The drug has adverse events that should be taken into account in secondary prevention.

Introducción: la atorvastatina ha sido usada en el manejo de la dislipidemia y se conoce poco sobre la eficacia y seguridad de la administración de atorvastatina en altas dosis para la prevención secundaria de eventos cardiovasculares mayores (MACE). Objetivo: evaluar el impacto de altas dosis de atorvastatina en la prevención secundaria de MACE y eventos adversos. Material y métodos: se realizó una revisión sistemática y un metaanálisis de las bases de datos Pubmed, Embase, Bireme y Cochrane Library Plus, con un alcance temporal de 1990 a julio de 2022. Se incluyeron seis ensayos clínicos aleatorios con un total de 29,333 pacientes que fueron tratados con dosis de 80 mg, 10 mg o placebo de Atorvastatina donde los resultados principales evaluados fueron los eventos cardiovasculares mayores (MACE), la mortalidad y la seguridad del tratamiento. Resultados: en el estudio comparativo entre el uso de Atorvastatina de 80 mg y otras terapias, se encontró un riesgo relativo (RR) de 0.8 (IC95%: 0.69-0.92), lo que representa una reducción del 20% en el riesgo (RRR) y un número necesario a tratar (NNT) de 30 a 55. En el análisis de los efectos adversos, se observó un RR de 2.37 (IC95%: 0.86-6.53) y un número necesario a dañar (NNH) de 14 a 19. El uso de atorvastatina de 80 mg se asocia con eventos adversos similares a dosis menores. Conclusiones: el uso de atorvastatina de 80 mg es efectivo en la prevención secundaria de evento cardiovascular mayor (MACE). El medicamento tiene eventos adversos que deben de tomarse en cuenta en la prevención secundaria.

Training in Radiation and Clinical Oncology in Europe.

The European population is strongly affected by cancer. Radiotherapy is roughly used in 50% of cancer patients in European countries. The increased cancer burden demands a new generation of radiation/clinical oncologist (RO/CO) that, besides a strong evidence-based oncological knowledge, will be ready for leadership in cancer care. The mutual recognition of professional qualifications of Radiation/Clinical Oncology in the EU needs training harmonization. The European Society of Radiotherapy and Oncology (ESTRO) and the European Union for Medical Specialties (UEMS) made important efforts toward a European Common Curriculum for RO/CO leadership in cancer care. If qualifications are mutually recognized, the training supporting these qualifications should be also harmonized. Since 1991, ESTRO produced several editions of the Core Curriculum in Radiation Oncology (1991, 2004, 2012, 2019). These Core Curricula were endorsed as European Training Requirements by the UEMS in 2004, 2013, and 2019. A core curriculum for clinical oncology was also produced to provide this harmonization tool to countries where radiation oncology is practiced inside the broader specialty of clinical oncology. New initiatives are in place to continuously adapt the training programs to the rapidly evolving cancer care organization.

Dose delivery reproducibility for PBS proton treatment of breast cancer patients with and without mask immobilization.

BACKGROUND: Setup reproducibility of the tissue in the proton beam path is critical in maintaining the planned clinical target volume (CTV) dose coverage and sparing the organs at risk (OAR). In this study, we retrospectively evaluated radiation therapy dose reproducibility for proton pencil beam scanning (PBS) treatment of breast cancer patients with and without mask immobilization. METHODS: Ninety-four patients treated between January 2019 and September 2022 with at least one verification CT scan (V-CT) in treatment position were included for this study. All patients were set up with arms up using the Orfit AIO patient positioning system, with (69 patients) or without (25 patients) mask immobilization in chin, neck, shoulder, upper arm, and chest areas. Two to three enface or near enface single field uniform dose PBS beams were optimized using a commercial treatment planning system. Prescription doses were 25 to 60 GyRBE in 5 to 45 fractions. Treatment plan doses re-calculated on V-CTs were compared to the corresponding planned doses. Cumulative doses were also calculated for patients with at least 3 V-CTs by deform and weighted sum doses from V-CTs to corresponding P-CTs. CTV D95%, ipsilateral-lung V40%, esophagus D0.01cc, and heart mean dose were evaluated and reported as percentages of prescription doses. Differences were large dose deteriorations (LDD) if: (1) CTV (V-CT/cumulative D95%) - (Planned D95%) < - 5%; or (2) Ipsilateral-lung (V-CT/cumulative V40%) - (Planned V40%) > 5%; or (3) Esophagus (V-CT/cumulative D0.01cc) - (Planned D0.01cc) > 10%; or (4) Heart (V-CT/cumulative mean) - (Planned mean) > 1.5%. RESULTS: On average, V-CT/cumulative and planned CTV/OAR dose parameter differences were less than 2.2%/1.7% and 3.4%/3.7% for masked and maskless patients, respectively. The percentages of patients with at least one CTV or OAR V-CT/cumulative dose LDD were 20.3%/25.0% and 72.0%/54.0% for masked and maskless patients, respectively. CONCLUSIONS: On average, masked/maskless setups achieved delivered and planned CTV/OAR dose parameters agreed within 2.2%/3.7% for PBS treatment of breast cancer patients in this study. Maskless patients had higher rate of CTV/OAR LDDs compared to masked patients. Dosimetric differences large enough to raise clinical concerns in either group were able to be addressed with replannings.

Functional effects of disease-associated variants reveal that the S1-M1 linker of the NMDA receptor critically controls channel opening.

The short pre-M1 helix within the S1-M1 linker (also referred to as the pre-M1 linker) between the agonist-binding domain (ABD, S1) and the M1 transmembrane helix of the NMDA receptor (NMDAR) is devoid of missense variants within the healthy population but is a locus for de novo pathogenic variants associated with neurological disorders. Several de novo variants within this helix have been identified in patients presenting early in life with intellectual disability, developmental delay, and/or epilepsy. In this study, we evaluated functional properties for twenty variants within the pre-M1 linker in GRIN1, GRIN2A, and GRIN2B genes, including six novel missense variants. The effects of pre-M1 variants on agonist potency, sensitivity to endogenous allosteric modulators, response time course, channel open probability, and surface expression were assessed. Our data indicated that virtually all of the variants evaluated altered channel function, and multiple variants had profound functional consequences, which may contribute to the neurological conditions in the patients harboring the variants in this region. These data strongly suggest that the residues within the pre-M1 helix play a key role in channel gating and are highly intolerant to genetic variation.

Technical note: Comprehensive evaluations of gantry and couch rotation isocentricities for implementing proton stereotactic radiosurgery.

BACKGROUND: Mechanical accuracy should be verified before implementing a proton stereotactic radiosurgery (SRS) program. Linear accelerator (Linac)-based SRS systems often use electronic portal imaging devices (EPIDs) to verify beam isocentricity. Because proton therapy systems do not have EPID, beam isocentricity tests of proton SRS may still rely on films, which are not efficient. PURPOSE: To validate that our proton SRS system meets mechanical precision requirements and to present an efficient method to evaluate the couch and gantry's rotational isocentricity for our proton SRS system. METHODS: A dedicated applicator to hold brass aperture for proton SRS system was designed. The mechanical precision of the system was tested using a metal ball and film for 11 combinations of gantry and couch angles. A more efficient quality assurance (QA) procedure was developed, which used a scintillator device to replace the film. The couch rotational isocentricity tests were performed using orthogonal kV x-rays with the couch rotated isocentrically to five positions (0°, 315°, 270°, 225°, and 180°). At each couch position, the distance between the metal ball in kV images and the imaging isocenter was measured. The gantry isocentricity tests were performed using a cone-shaped scintillator and proton beams at five gantry angles (0°, 45°, 90°, 135°, and 180°), and the isocenter position and the distance of each beam path to the isocenter were obtained. Daily QA procedure was performed for 1 month to test the robustness and reproducibility of the procedure. RESULTS: The gantry and couch rotational isocentricity exhibited sub-mm precision, with most measurements within ±0.5 mm. The 1-month QA results showed that the procedure was robust and highly reproducible to within ±0.2 mm. The gantry isocentricity test using the cone-shaped scintillator was accurate and sensitive to variations of ±0.2 mm. The QA procedure was efficient enough to be completed within 30 min. The 1-month isocentricity position variations were within 0.5 mm, which demonstrating that the overall proton SRS system was stable and precise. CONCLUSION: The proton SRS Winston-Lutz QA procedure using a cone-shaped scintillator was efficient and robust. We were able to verify radiation delivery could be performed with sub-mm mechanical precision.

Sudden Cardiac Arrest During a Sedated Cardiac Magnetic Resonance Study in a Nonsyndromic Child with Evolving Supravalvar Aortic Stenosis Due to Familial ELN Mutation.

Supravalvar aortic stenosis (SVAS) is a less common but clinically important form of left ventricular outflow tract obstruction, and commonly associated with Williams syndrome (WS). SVAS outside of WS may also occur sporadically or in a familial form, often with identifiable mutations in the elastin (ELN) gene. While risk of sudden cardiac death in patients with SVAS has been extensively described in the context of WS, less is known about risk in patients with isolated SVAS. We report a case of a nonsyndromic two-year-old boy with evolving manifestations of SVAS who developed sudden cardiac arrest and death during a sedated cardiac magnetic resonance imaging study. A strong family history of SVAS was present and targeted genetic testing identified an ELN gene mutation in the boy's affected father and other paternal relatives. We review risk factors found in the literature for SCA in SVAS patients and utilize this case to raise awareness of the risk of cardiac events in these individuals even in the absence of WS or severe disease. This case also underscores the importance of genetic testing, including targeted panels specifically looking for ELN gene mutations, in all patients with SVAS even in the absence of phenotypic concerns for WS or other genetic syndromes.

Small GTPase Ran: Depicting the nucleotide-specific conformational landscape of the functionally important C-terminus.

The small GTPase Ran is the main regulator of the nucleo-cytoplasmic import and export through the nuclear pore complex. It functions as a molecular switch cycling between the GDP-bound inactive and GTP-bound active state. It consists of a globular (G) domain and a C-terminal region, which is bound to the G-domain in the inactive, GDP-bound states. Crystal structures of the GTP-bound active form complexed with Ran binding proteins (RanBP) show that the C-terminus undergoes a large conformational change, embracing Ran binding domains (RanBD). Whereas in the crystal structures of macromolecular complexes not containing RanBDs the structure of the C-terminal segment remains unresolved, indicating its large conformational flexibility. This movement could not have been followed either by experimental or simulation methods. Here, starting from the crystal structure of Ran in both GDP- and GTP-bound forms we show how rigid the C-terminal region in the inactive structure is during molecular dynamics (MD) simulations. Furthermore, we show how MD simulations of the active form are incapable of mapping the open conformations of the C-terminus. By using the MDeNM (Molecular Dynamics with excited Normal Modes) method, we were able to widely map the conformational surface of the C-terminus of Ran in the active GTP-bound form, which allows us to envisage how it can embrace RanBDs.

Histopathological maladaptive changes in the explanted human mitral leaflets correlate with changes in echocardiographic leaflet morphology and the severity of ischaemic mitral regurgitation.

AIMS: Several changes of the mitral valve (MV) morphology have been previously documented in ischaemic mitral regurgitation (IMR) upon macro and microscopic examination. This study aimed to correlate echocardiographic MV thickening with IMR severity and to delineate the histopathological basis of valve thickening from the explanted leaflets. METHODS AND RESULTS: Two hundred and fifty patients were included in the echo-group; of these, 48 patients (19.2%) underwent surgical mitral valve replacement (MVR), including them in the histology-group. By echocardiography, the thickness of the anterior and posterior leaflet was more extensive in moderate to severe IMR, P < 0.001. Histology-group: patients were divided into two groups based on the median thickness: those with cusp thickness <0.42 cm in Group 1, and ≥0.42 cm in Group 2. The thickness of the base and cusp was more significant in Group 2, P < 0.05 in both. Group 2 biopsies were characterized by involvement of the three leaflet segments, myxoid tissue, and fibrosis deposition. Thicker leaflets were associated with a greater degree of mitral regurgitation (MR), P < 0.0001. In the echo-group, a median leaflet thickness of 3.5 mm of the anterior and posterior MV was independently associated with moderate to severe ischaemic MR [odds ratio (OR) 2.88, P < 0.01] and (OR 10.8, P < 0.001), respectively. CONCLUSION: In ischaemic MR, the thicker the cusps, the worse the MR. Leaflet thickening was due to the myxoid and fibrosis deposition and was detected by echocardiography. Therefore, this method can be helpful in the evaluation of valve remodelling.

Incorporation of the emotional indicators of the patient journey into healthcare organization management.

BACKGROUND: In recent years, attempts have been made to incorporate patients' experiences into healthcare processes, to complement clinical indicators, with what are known as patient-reported outcome measures (PROMs) and patient-reported experience measures (PREMs). While the research into PROMs is more developed, the application of PREMs faces some difficulties. The incorporation of emotional indicators into assessments of the experience is an area that remains to be explored. OBJECTIVES: This study proposes a new technique to analyse the emotions experienced by patients during the care process, examines how these emotions influence their satisfaction and propose that if healthcare services focus more on patients' emotions, they can improve the effectiveness of the sector. METHODS: The first, qualitative stage, gathered data from patients to design a patient journey (PJ). The PJ was then reproduced as a video. In a subsequent, quantitative stage, the video was shown to experimental participants, and their emotions were measured through facial expression analysis and a questionnaire. RESULTS: A new technique to gather emotional data showed that the emotions patients experience do not affect their satisfaction with their clinical care or the physical aspects of the process. However, their emotions did affect their satisfaction with people and organizations. CONCLUSIONS: The importance of the emotional component of patients' experiences was underlined. Therefore, healthcare organizations should take account of this dimension, as well as the cognitive, to increase patient satisfaction and improve their care processes. Understanding the impact of the emotions identified at the subconscious level can help improve the patient experience. A new methodology was applied that may help health professionals to collect emotional data about patients' experiences and to develop PREMs. PATIENT/PUBLIC CONTRIBUTION: Patients were involved in all stages of this research. In the exploratory phase, some helped define the touchpoints of the PJ. The data from the subsequent experimental phase were collected from another group, and the emotions they experienced were identified through the analysis of their facial expressions. Based on the results of this study, a working group including patients has been established to work on improvements in the PJ.

A neurodevelopmental disorder associated with an activating de novo missense variant in ARF1.

ADP-ribosylation factor 1 (ARF1) is a small GTPase that regulates membrane traffic at the Golgi apparatus and endosomes through recruitment of several coat proteins and lipid-modifying enzymes. Here, we report a pediatric patient with an ARF1-related disorder because of a monoallelic de novo missense variant (c.296 G > A; p.R99H) in the ARF1 gene, associated with developmental delay, hypotonia, intellectual disability and motor stereotypies. Neuroimaging revealed a hypoplastic corpus callosum and subcortical white matter abnormalities. Notably, this patient did not exhibit periventricular heterotopias previously observed in other patients with ARF1 variants (including p.R99H). Functional analysis of the R99H-ARF1 variant protein revealed that it was expressed at normal levels and properly localized to the Golgi apparatus; however, the expression of this variant caused swelling of the Golgi apparatus, increased the recruitment of coat proteins such as coat protein complex I, adaptor protein complex 1 and GGA3 and altered the morphology of recycling endosomes. In addition, we observed that the expression of R99H-ARF1 prevented dispersal of the Golgi apparatus by the ARF1-inhibitor brefeldin A. Finally, protein interaction analyses showed that R99H-ARF1 bound more tightly to the ARF1-effector GGA3 relative to wild-type ARF1. These properties were similar to those of the well-characterized constitutively active Q71L-ARF1 mutant, indicating that the pathogenetic mechanism of the R99H-ARF1 variant involves constitutive activation with resultant Golgi and endosomal alterations. The absence of periventricular nodular heterotopias in this R99H-ARF1 subject also indicates that this finding may not be a consistent phenotypic expression of all ARF1-related disorders.