Laboratory diagnosis of rare diseases

Inborn errors of metabolism (IEM) are a group of diseases whose diagnosis is usually performed by quantification of several metabolites in biological fluids. The aim of this review is to report the role of the laboratory in IEM diagnosis, highlighting the methods available at present and their advantages and limitations. In conclusion, the huge number of recognized IEMs strongly advises the implementation of new high- output technologies in the laboratories devoted to IEM diagnosis. Although these technologies offer a high diagnostic ability, routine analyses are still very important, as well as consideration of several variables involved in biological sample collection and disease expression that may lead to misdiagnosis of IEMs.     

Low height and rare diseases

Low stature is the main reason of consultation in paediatric endocrinology. In a high percentage of cases, its etiology is clear and fundamentally answers to variants of normality. However, in approximately 20% of cases low stature is pathological and requires exhaustive studies. The association of rare diseases (RD) with low height is very frequent. In this article we review the etiology of low height, describing: - The genetic forms of the growth hormone (GH), whether isolated or associated with malformations of the average line or others. - Those which are of great importance due to their clinical repercussion, such as Turner's Syndrome, Noonan's Syndrome and Willi-Prader's Syndrome. - The frequent osseous dysplasias, in some cases with genetic alterations of the SHOX gene, situated in the short arm of the Xp chromosome. The importance of these diagnoses lies in the possibility of carrying out early and efficient treatment, in some of them, with GH. In conclusion, the diagnosis of rare diseases with low height is a current and normal challenge in paediatric endocrinology due to the great advances in molecular genetics and the possibility of treatment in some of them. It always involves a multidisciplinary approach due to the frequent association of pathology it presents, and, in its turn, it offers the possibility of carrying out timely genetic counselling.     

On-line resources in dealing with rare diseases

The increase in scientific knowledge and the need for its transmission to health professionals and patients has resulted in the creation of websites as a useful tool. In low prevalence diseases, such as rare diseases (RDs), sites are being created by scientific societies, institutions and patients. This section reviews the most important websites dealing with RDs both nationally and internationally.     

Coming together to combat rare diseases

The European Commission is increasingly supporting collaborative initiatives focused on research into treatments and drugs for rare diseases, but lack of funding continues to be an issue.     

Orphanet: a European database for rare diseases

Orphanet is a European initiative that aims to improve the management and treatment of rare diseases. It comprises a database dedicated to information on rare diseases and orphan drugs, and offers services adapted to the needs of patients and their families, health professionals, and researchers. The database can be accessed through the website (www.orpha.net) and has some interesting options for searching, for example research projects, support groups or searching by clinical signs. Health professionals are encouraged to add activities concerning rare diseases to the database.     

The pharmacist, rare diseases and orphan medicines

Treatment of rare diseases is often complicated due to the difficulties posed by the research and development of medicines by the pharmacological industry. One of the greatest concerns of this group of patients, which is both scarce and diverse, is access to available medicines. The European Medicine Agency establishes the term orphan medicines and the incentives and bases for their commercialisation. Due to their special characteristics, the majority of orphan medicines require suitable vigilance and control. The hospital pharmacy services are actively involved in their management and supply, as well as in a correct pharmacotherapeutic monitoring of the patients.     

浙江省2007－2017年罕见病住院病例特征分析

目的 分析2007-2017年浙江省24 388例罕见病住院病例特征，为制定罕见病防控策略提供依据。方法 收集2007-2017年浙江省10家三级甲等（三甲）医院罕见病住院病例资料和各年度住院数，进行描述性统计分析。结果 罕见病病例共24 388例，占住院总例数的2.69‰（24 388/9 054 201），病例数居前3位的疾病类型依次为"血液和造血器官疾病以及某些涉及免疫机能的异常"（占32.81%，8 001/24 388）、"先天性畸形、变形和染色体异常"（占24.87%，6 065/24 388）和"神经系统疾病"（占19.01%，4 635/24 388）；2007-2017年罕见病病例数呈逐年增长趋势，年均增幅19.69%，而罕见病例数占同期住院总例数比例仅在2016-2017年明显上升，各类型罕见病时间分布呈不同特征；罕见病的病例数男女性别比为1.35：1（13 990/10 398），男女性别比最高的3类疾病依次为"消化系统疾病"（4.45：1，1 180/265）、"损伤、中毒和外因的某些其他后果"（3.51：1，281/80）和"神经系统疾病"（2.26：1，3 213/1 422）；各年龄段罕见病类型、各类型罕见病年龄分布均呈不同特征；病例数居前10位的疾病占全部罕见病例数的53.55%（13 060/24 388），其中前3位疾病分别为成人粒细胞缺乏症（14.41%，3 515/24 388）、皮质基底核退化症（7.60%，1 854/24 388）和亨诺克-舍恩莱因紫癜（6.01%，1 466/24 388）。结论 本研究分析的浙江省2007-2017年24 388例罕见病住院病例的特征资料，是推动我国罕见病的研究、监测或登记数据库构建、制定防控策略的参考依据。     

Population-based and family-based designs to analyze rare variants in complex diseases

Genotyping of rare variants on a large scale is now possible using next-generation sequencing. Sample selection is a crucial step in designing the genetic study of a complex disease, and knowledge of the efficiency and limitations of population-based and family-based designs can help researchers make the appropriate choice. The nine contributions to Group 5 of Genetic Analysis Workshop 17 evaluate population-based and family-based designs by comparing the results obtained with various methods applied to the mini-exome simulations. These simulations consisted of 200 replicates composed of unrelated individuals and eight extended pedigrees with genotypes and various phenotypes. The methods tested for association with a population-based and/or a family-based design, tested for linkage with a family-based design, or estimated heritability. We summarize the strengths and weaknesses of both designs. Although population-based designs seem more suitable for detecting the effect of multiple rare variants, family-based designs can potentially enrich the sample in rare variants, for which the effect would be concealed at the population level. However, as of today, the main limitation is still the high cost of next-generation sequencing.     

Erratum to: Ethical aspects of clinical trials in rare diseases

Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz -     

Clinical experience during the paediatric undergraduate course.

Medical students at the Cambridge Clinical School are provided with a list of 42 core conditions they should encounter and 20 core skills they should perform during their attachment. By self-completion questionnaires we assessed their clinical experience and the amount of teaching they received, relating the results to marks gained in end-of-attachment assessments. 103 (93%) of 110 students in year one and 123 (96%) of 128 in year two completed the questionnaires. Of the 42 core conditions, 13 were seen by under 70% of the students in year one. In year two, exposure rate increased for 26 core conditions by a median of 7% (range 2-40) and decreased in 13 core conditions by a median value 4% (range 5-13) (P = 0.0005, chi 2). Only mandatory core skills were performed by over 90% of students. 5% of students did not perform any newborn examinations and under 60% observed neonatal resuscitation or a high-risk delivery. Students' core condition score was associated with their core skill score (r = 0.5), hospital grade (r = 0.3) and exposure to acute paediatrics (r = 0.3) (P < 0.005). There was no significant association between clinical experience and the objective examination score or the amount of teaching received. There was an inverse association between the number of students at a hospital and the number of core conditions with an exposure rate above 70% at that hospital (r = 0.7, P < 0.05). This study suggests that clinical experience may be better judged by the clinical supervisor than by assessment of theoretical knowledge.