A novel missense variant in the ATPase domain of ATP8A2 and review of phenotypic variability of ATP8A2-related disorders caused by missense changes.

ATPase, class 1, type 8A, member 2 (ATP8A2) is a P4-ATPase with a critical role in phospholipid translocation across the plasma membrane. Pathogenic variants in ATP8A2 are known to cause cerebellar ataxia, mental retardation, and disequilibrium syndrome 4 (CAMRQ4) which is often associated with encephalopathy, global developmental delay, and severe motor deficits. Here, we present a family with two siblings presenting with global developmental delay, intellectual disability, spasticity, ataxia, nystagmus, and thin corpus callosum. Whole exome sequencing revealed a homozygous missense variant in the nucleotide binding domain of ATP8A2 (p.Leu538Pro) that results in near complete loss of protein expression. This is in line with other missense variants in the same domain leading to protein misfolding and loss of ATPase function. In addition, by performing diffusion-weighted imaging, we identified bilateral hyperintensities in the posterior limbs of the internal capsule suggesting possible microstructural changes in axon tracts that had not been appreciated before and could contribute to the sensorimotor deficits in these individuals.

Biallelic variation in the choline and ethanolamine transporter FLVCR1 underlies a pleiotropic disease spectrum from adult neurodegeneration to severe developmental disorders.

FLVCR1 encodes Feline leukemia virus subgroup C receptor 1 (FLVCR1), a solute carrier (SLC) transporter within the Major Facilitator Superfamily. FLVCR1 is a widely expressed transmembrane protein with plasma membrane and mitochondrial isoforms implicated in heme, choline, and ethanolamine transport. While Flvcr1 knockout mice die in utero with skeletal malformations and defective erythropoiesis reminiscent of Diamond-Blackfan anemia, rare biallelic pathogenic FLVCR1 variants are linked to childhood or adult-onset neurodegeneration of the retina, spinal cord, and peripheral nervous system. We ascertained from research and clinical exome sequencing 27 individuals from 20 unrelated families with biallelic ultra-rare missense and predicted loss-of-function (pLoF) FLVCR1 variant alleles. We characterize an expansive FLVCR1 phenotypic spectrum ranging from adult-onset retinitis pigmentosa to severe developmental disorders with microcephaly, reduced brain volume, epilepsy, spasticity, and premature death. The most severely affected individuals, including three individuals with homozygous pLoF variants, share traits with Flvcr1 knockout mice and Diamond-Blackfan anemia including macrocytic anemia and congenital skeletal malformations. Pathogenic FLVCR1 missense variants primarily lie within transmembrane domains and reduce choline and ethanolamine transport activity compared with wild-type FLVCR1 with minimal impact on FLVCR1 stability or subcellular localization. Several variants disrupt splicing in a mini-gene assay which may contribute to genotype-phenotype correlations. Taken together, these data support an allele-specific gene dosage model in which phenotypic severity reflects residual FLVCR1 activity. This study expands our understanding of Mendelian disorders of choline and ethanolamine transport and demonstrates the importance of choline and ethanolamine in neurodevelopment and neuronal homeostasis.

Genetic blueprint of congenital muscular dystrophies with brain malformations in Egypt: A report of 11 families.

Congenital muscular dystrophies (CMDs) are a group of rare muscle disorders characterized by early onset hypotonia and motor developmental delay associated with brain malformations with or without eye anomalies in the most severe cases. In this study, we aimed to uncover the genetic basis of severe CMD in Egypt and to determine the efficacy of whole exome sequencing (WES)-based genetic diagnosis in this population. We recruited twelve individuals from eleven families with a clinical diagnosis of CMD with brain malformations that fell into two groups: seven patients with suspected dystroglycanopathy and five patients with suspected merosin-deficient CMD. WES was analyzed by variant filtering using multiple approaches including splicing and copy number variant (CNV) analysis. We identified likely pathogenic variants in FKRP in two cases and variants in POMT1, POMK, and B3GALNT2 in three individuals. All individuals with merosin-deficient CMD had truncating variants in LAMA2. Further analysis in one of the two unsolved cases showed a homozygous protein-truncating variant in Feline Leukemia Virus subgroup C Receptor 1 (FLVCR1). FLVCR1 loss of function has never been previously reported. Yet, loss of function of its paralog, FLVCR2, causes lethal hydranencephaly-hydrocephaly syndrome (Fowler Syndrome) which should be considered in the differential diagnosis for dystroglycanopathy. Overall, we reached a diagnostic rate of 86% (6/7) for dystroglycanopathies and 100% (5/5) for merosinopathy. In conclusion, our results provide further evidence that WES is an important diagnostic method in CMD in developing countries to improve the diagnostic rate, management plan, and genetic counseling for these disorders.

Removal of pomt1 in zebrafish leads to loss of α-dystroglycan glycosylation and dystroglycanopathy phenotypes.

Biallelic mutations in Protein O-mannosyltransferase 1 (POMT1) are among the most common causes of a severe group of congenital muscular dystrophies (CMDs) known as dystroglycanopathies. POMT1 is a glycosyltransferase responsible for the attachment of a functional glycan mediating interactions between the transmembrane glycoprotein dystroglycan and its binding partners in the extracellular matrix (ECM). Disruptions in these cell-ECM interactions lead to multiple developmental defects causing brain and eye malformations in addition to CMD. Removing Pomt1 in the mouse leads to early embryonic death due to the essential role of dystroglycan during placental formation in rodents. Here, we characterized and validated a model of pomt1 loss of function in the zebrafish showing that developmental defects found in individuals affected by dystroglycanopathies can be recapitulated in the fish. We also discovered that pomt1 mRNA provided by the mother in the oocyte supports dystroglycan glycosylation during the first few weeks of development. Muscle disease, retinal synapse formation deficits, and axon guidance defects can only be uncovered during the first week post fertilization by generating knock-out embryos from knock-out mothers. Conversely, maternal pomt1 from heterozygous mothers was sufficient to sustain muscle, eye, and brain development only leading to loss of photoreceptor synapses at 30 days post fertilization. Our findings show that it is important to define the contribution of maternal mRNA while developing zebrafish models of dystroglycanopathies and that offspring generated from heterozygous and knock-out mothers can be used to differentiate the role of dystroglycan glycosylation in tissue formation and maintenance.

Outcomes in patients with metastatic bladder cancer in the USA: a retrospective electronic medical record study.

Aim: Investigate the effectiveness of chemotherapy for first-line (1L) treatment of metastatic bladder cancer (mBC). Methods: Retrospective cohort study evaluating treatment patterns/outcomes in 1155 mBC patients receiving initial treatment in the community practice setting from January 2010 to June 2014, and followed through July 2016. Results: The most commonly utilized 1L and second-line (2L) regimens were platinum-based and taxane-based, respectively. Median (95% CI) OS for all patients from 1L initiation was 12.8 months (11.7-14.6), and median OS for all 2L regimens was 9.4 months (8.2-11.1). Conclusion: mBC patients eligible for and who received cis-based regimens experienced better OS results. Poor renal function was a key driver of cis-ineligibility. The various monotherapy and combination chemotherapy regimens in 2L produced relatively short OS outcomes.

Survival Rates and Health Care Costs for Patients With Advanced Bladder Cancer Treated and Untreated With Chemotherapy.

BACKGROUND: Systemic chemotherapy has long been the standard of care for advanced bladder cancer, but its cost implications are poorly understood. The objective of this analysis was to estimate survival and health care costs for patients with stage IV bladder cancer who did or did not receive chemotherapy. PATIENTS AND METHODS: This was a retrospective cohort study of patients identified in the Surveillance, Epidemiology, and End Results-Medicare database with a new primary diagnosis of stage IV bladder cancer between January 2007 and December 2011. Survival and health care visits and costs following the date of diagnosis were determined for treated and untreated patients. Costs were expressed in 2016 US dollars. RESULTS: A total of 1215 patients were diagnosed with stage IV bladder cancer, of whom 411 (33.8%) were treated with chemotherapy and 804 (66.2%) were untreated. Median overall survival was 10 months longer for treated than for untreated patients: 13.2 (95% confidence interval, 12.3-14.1) months versus 3.2 (95% confidence interval, 3.0-3.5) months. Treated patients had fewer per-patient-per-month (PPPM) health care visits than untreated patients (7.5 vs. 10.2, P < .01) and lower total PPPM health care costs ($10,707 vs. $18,935). Overall mean total lifetime costs were greater for treated than for untreated patients ($139,893 vs. $66,829, P < .05), which was driven by an approximate 4-fold increase in life expectancy for the treated patients. CONCLUSION: Approximately two thirds of patients diagnosed with stage IV bladder cancer were not treated with systemic chemotherapy. Increasing the percentage of treated patients in this population could potentially extend overall survival while simultaneously lowering PPPM costs.

Budgetary Impact of Cabazitaxel Use After Docetaxel Treatment for Metastatic Castration-Resistant Prostate Cancer.

BACKGROUND: With the approval of several new treatments for metastatic castration-resistant prostate cancer (mCRPC), budgetary impact is a concern for health plan decision makers. Budget impact models (BIMs) are becoming a requirement in many countries as part of formulary approval or reimbursement decisions. Cabazitaxel is a second-generation taxane developed to overcome resistance to docetaxel and is approved for the treatment of patients with mCRPC previously treated with a docetaxel-containing regimen. OBJECTIVE: To estimate a 1-year projected budget impact of varying utilization rates of cabazitaxel as a second-line treatment for mCRPC following docetaxel, using a hypothetical U.S. private managed care plan with 1 million members. METHODS: A BIM was developed to evaluate costs for currently available treatment options for patients with mCRPC previously treated with docetaxel. Treatments included in the model were cabazitaxel, abiraterone acetate, enzalutamide, and radium-223, with utilization rates derived from market research data. Medication costs were calculated according to published pricing benchmarks factored by dosing and duration of therapy as stated in the prescribing information for each agent. Published rates and costs of grade 3-4 adverse events were also factored into the model. In addition, the model reports budget impact under 2 scenarios. In the first base-case scenario, patient out-of-pocket costs were subtracted from the total cost of treatment. In the second scenario, all treatment costs were assumed to be paid by the plan. RESULTS: In a hypothetical 1 million-member health plan population, 100 patients were estimated to receive second-line treatment for mCRPC after treatment with docetaxel. Using current utilization rates for the 4 agents of interest, the base-case scenario estimated the cost of second-line treatment after docetaxel to be $6,331,704, or $0.528 per member per month (PMPM). In a scenario where cabazitaxel use increases from the base-rate case of 24% to a hypothetical rate of 33%, the PMPM cost would decrease to $0.524, reflecting a cost saving of $0.004 PMPM and equating to incremental savings of $49,546, or $497 per patient per year (PPPY). In the second scenario, when out-of-pocket costs were not considered, the cost of second-line treatment after docetaxel was estimated as $6,733,594, or $0.561 PMPM. With a hypothetical increase in cabazitaxel use (24%-33%), the PMPM cost would decrease to $0.554, reflecting savings of $0.007 PMPM and equating to incremental savings of $86,136, or $864 PPPY. The primary driver of cost savings with increased cabazitaxel use was lower acquisition cost. One-way sensitivity analyses revealed that the model results were robust over a wide range of input values (utilization, prevalence, and population parameters). CONCLUSIONS: In the presented BIM, an increase in cabazitaxel use is expected to result in modest cost savings to the health plan. Patient coinsurance savings may also be realized based on applicable Medicare Part B and Part D calculations. This BIM presents an objective, comprehensive, robust, and user-adaptable tool that health plans and medical decision makers may use to evaluate potential economic impact of formulary and reimbursement decisions. DISCLOSURES: Research and analysis were funded by Sanofi US. The sponsor had the opportunity to review the final draft; however, the authors were responsible for all content and editorial decisions. Flannery, Drea, Hudspeth, and Miao are employees of Sanofi. Miao is an owner of stock in Sanofi. Corman, Gao, and Xue are employees of Pharmerit International and served as consultants to Sanofi during this study. All authors contributed to study design and data collection and analysis. The manuscript was written by Flannery, along with the other authors, and revised by all the authors.