Cornelia de Lange syndrome (CdLS) is an archetypical genetic syndrome that is characterized by intellectual disability, well-defined facial features, upper limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in any one of seven genes, all of which have a structural or regulatory function in the cohesin complex. Although recent advances in next-generation sequencing have improved molecular diagnostics, marked heterogeneity exists in clinical and molecular diagnostic approaches and care practices worldwide. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria, both for classic CdLS and non-classic CdLS phenotypes, molecular investigations, long-term management and care planning.

There is a clear need for further research with appropriate study designs and statistical analyses, with more attention to confounding factors such as media coverage, to understand the impact of safety-related regulatory action.

SMC1A encodes one of the proteins of the cohesin complex. SMC1A variants are known to cause a phenotype resembling Cornelia de Lange syndrome (CdLS). Exome sequencing has allowed recognizing SMC1A variants in individuals with encephalopathy with epilepsy who do not resemble CdLS. We performed an international, interdisciplinary study on 51 individuals with SMC1A variants for physical and behavioral characteristics, and compare results to those in 67 individuals with NIPBL variants. For the Netherlands all known individuals with SMC1A variants were studied, both with and without CdLS phenotype. Individuals with SMC1A variants can resemble CdLS, but manifestations are less marked compared to individuals with NIPBL variants: growth is less disturbed, facial signs are less marked (except for periocular signs and thin upper vermillion), there are no major limb anomalies, and they have a higher level of cognitive and adaptive functioning. Self-injurious behavior is more frequent and more severe in the NIPBL group. In the Dutch group 5 of 13 individuals (all females) had a phenotype that shows a remarkable resemblance to Rett syndrome: epileptic encephalopathy, severe or profound intellectual disability, stereotypic movements, and (in some) regression. Their missense, nonsense, and frameshift mutations are evenly spread over the gene. We conclude that SMC1A variants can result in a phenotype resembling CdLS and a phenotype resembling Rett syndrome. Resemblances between the SMC1A group and the NIPBL group suggest that a disturbed cohesin function contributes to the phenotype, but differences between these groups may also be explained by other underlying mechanisms such as moonlighting of the cohesin genes.

Safety information of drugs does not always reach healthcare professionals through DHPCs. To improve current risk communication of drug safety issues, alternative and/or additional methods of risk communication should be developed using electronic methods and medical journals. Moreover, (additional) risk communication coming from an independent source such as the MEB should be considered. Special effort is needed to reach GPs.

Serious safety issues relating to drugs are communicated to health-care professionals via Direct Health-Care Professional Communications (DHPCs). We explored which characteristics determined the impact of DHPCs issued in the Netherlands for ambulatory-care drugs (2001-2008). With multiple linear regression, we examined the impact on the relative change in new drug use post-DHPC of the following: time to DHPC, trend in use, degree of innovation, specialist drug, first/repeated DHPC, DHPC template, and type of safety issue. DHPCs have less impact on use of specialist drugs than nonspecialist drugs (P < 0.05). The DHPCs' impact increased after availability of a template emphasizing the main problem (P < 0.05), and for safety issues with a risk of death and/or disability (both P < 0.05) (adjusted R² = 0.392). Risk communication can be effective, specifically in case of well-structured information, and very serious safety issues. Effectiveness may improve by tailoring DHPCs and adding other communication channels, for example for drugs that are increasingly being used.

Self-injurious behavior (SIB) is a relatively common behavior in individuals with intellectual disabilities (ID). Severe SIB can be devastating and potentially life-threatening. There is increasing attention for somatic substrates of behavior in genetic syndromes, and growing evidence of an association between pain and discomfort with SIB in people with ID and genetic syndromes. In this review on SIB phenomenology in people with ID in general and in twelve genetic syndromes, we summarize different SIB characteristics across these etiologically distinct entities and identify influencing factors. We demonstrate that the prevalence of SIB in several well-known genetic intellectual disability syndromes is noticeably higher than in individuals with ID in general, and that characteristics such as age of onset and topographies differ widely across syndromes. Each syndrome is caused by a mutation in a different gene, and this allows detection of several pathways that lead to SIB. Studying these with the behavioral consequences as specific aim will be an important step toward targeted early interventions and prevention.

Introduction Development and behaviour in Cornelia de Lange Syndrome (CdLS), including autism characteristics, have been described infrequently stratified to genetic cause and only a few studies have considered behavioural characteristics in relation to developmental level. Here, we describe the behavioural phenotype in individuals with CdLS with SMC1A variants. Methods We performed an international, interdisciplinary study on 51 individuals with SMC1A variants. Results of questionnaire studies are compared to those in individuals with Down Syndrome and with Autism Spectrum Disorder. Results on cognition and self‐injurious behaviour (SIB) are compared to those in individuals with CdLS caused by NIPBL variants. For Dutch participants with SMC1A variants we performed direct in‐person assessments of cognition, autism, and added an interview and questionnaire on adaptive behaviour and sensory processing. Results Individuals with SMC1A variants show a higher cognitive level and less SIB than individuals with NIPBL variants. Individuals with SMC1A variants without classic CdLS phenotype but with a Rett‐like phenotype show more severe intellectual disability and more SIB compared to those with a CdLS phenotype. Autism is less present if outcomes in direct in‐person assessments are evaluated taking developmental level into account compared to results based on a questionnaire. Conclusions Behaviour in individuals with CdLS should be evaluated taking genetic cause into account. Detailed interdisciplinary approaches are of clinical importance to inform tailored care and may eventually improve quality of life of patients and families.

The effect of Direct Healthcare Professional Communications (DHPCs) informing health-care providers of serious drug safety issues has been questioned. The aim of this study was to evaluate the impact of DHPCs on drug use.Nationwide dispensing data for the period 2000–2008 for new users of 46 drugs with one or more DHPCs were assessed. Impact on short-term volume of use was evaluated with regression models, and the presence of long-term changes in use was evaluated with interrupted time series analyses incorporating preexisting trends. The short-term prescription level was lower post-DHPC in 28 (48.3%) of 58 cases. Twenty (34.5%) DHPCs resulted in long-term changes in use. A long-term mean reduction in use was observed in 26.7% of cases (95% confidence interval, −15.2 to −38.2%).Long-term changes in use were not significantly related to preexisting trends in use. Although short- and long-term decreases in use were observed after only half and a third of DHPCs, respectively, the decrease was substantial.