Effects of naturally occurring missense mutations and G525V in the hydratase domain of human d-bifunctional protein on hydratase activity

d-bifunctional protein (d-BP) deficiency is thought to lead to severe lipid metabolism disorders. To investigate the effect of naturally occurring missense mutations in the hydratase domain in d-BP, we constructed several d-BP hydratase variants and measured their activities. Missense mutations at sites whose conservation rates among 30 eukaryotes were < 70% did not affect hydratase activity. We predicted that missense mutations of highly conserved amino acids would markedly reduce activity. However, R562H and R562L, naturally occurring missense mutations of highly conserved amino acids, did not reduce activity. This result suggests that a missense mutation in a highly conserved amino acid does not always lead to severe lipid metabolism disorders. We also investigated the effect of G525V, which had been found in a mildly symptomatic patient with d-BP deficiency who was heterozygous for G525 and G658X. G525V markedly reduced hydratase activity. We had predicted that heterozygous G525V and G658X would lead to severely disordered lipid metabolism. However, the symptoms were inconsistent with this prediction. Characterizing mutations in the d-BP gene and the symptoms of d-BP deficiency may require pleiotropy, not only in vitro, studies

Enhancing evidence-informed policymaking in medicine and healthcare: stakeholder involvement in the Commons Project for rare diseases in Japan

Abstract Background Although stakeholder involvement in policymaking is attracting attention in the fields of medicine and healthcare, a practical methodology has not yet been established. Rare-disease policy, specifically research priority setting for the allocation of limited research resources, is an area where evidence generation through stakeholder involvement is expected to be effective. We generated evidence for rare-disease policymaking through stakeholder involvement and explored effective collaboration among stakeholders. Methods We constructed a space called ‘Evidence-generating Commons’, where patients, family members, researchers, and former policymakers can share their knowledge and experiences and engage in continual deliberations on evidence generation. Ten rare diseases were consequently represented. In the ‘Commons’, 25 consecutive workshops were held predominantly online, from 2019 to 2021. These workshops focused on (1) clarification of difficulties faced by rare-disease patients, (2) development and selection of criteria for priority setting, and (3) priority setting through the application of the criteria. For the first step, an on-site workshop using sticky notes was held. The data were analysed based on KJ method. For the second and third steps, workshops on specific themes were held to build consensus. The workshop agendas and methods were modified based on participants’ feedback. Results The ‘Commons’ was established with 43 participants, resulting in positive effects such as capacity building, opportunities for interactions, mutual understanding, and empathy among the participants. The difficulties faced by patients with rare diseases were classified into 10 categories. Seven research topics were identified as priority issues to be addressed including ‘impediments to daily life’, ‘financial burden’, ‘anxiety’, and ‘burden of hospital visits’. This was performed by synthesising the results of the application of the two criteria that were particularly important to strengthen future research on rare diseases. We also clarified high-priority research topics by using criteria valued more by patients and family members than by researchers and former policymakers, and criteria with specific perspectives. Conclusion We generated evidence for policymaking in the field of rare diseases. This study’s insights into stakeholder involvement can enhance evidence-informed policymaking. We engaged in comprehensive discussions with policymakers regarding policy implementation and planned analysis of the participants’ experiences in this project