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Due to an experienced gap in care for adolescents with an autism spectrum disorder (ASD) and an intellectual disability (ID), an interdisciplinary outpatient clinic was initiated by child- and adolescent psychiatry services together with intellectual disability physicians in the Rotterdam region in 2017.Evaluaa id="_idTextAnchor018"/ation of the ASD-ID outpatient clinic.A retra id="_idTextAnchor019"/aospective chart review study of the first year of the ASD-ID outpatient clinic was performed. The care specific traits of the adolescents who visited the ASD-ID outpatient clinic, their health care costs and the effect of the ASD-ID outpatient clinic on both the health care costs and the patient outflow was compared to the traits of the adolescents of the autism outpatient clinic.32 adoa id="_idTextAnchor020"/alescents who were referred to the ASD-ID outpatient clinic were comparable to 204 adolescents of the autism outpatient clinic in age (mean 16.5 years) and gender (75% male). They had 39% more DSM-IV classifications, were in care 3.7 years longer and had 44% more health care costs. After visiting the ASD-ID outpatient clinic, 50% of the adolescents were transferred within a year and 100% within three years to a intellectual disability physician.Adolesa id="_idTextAnchor021"/acents with ASD and ID are a group with a substantial demand for care who deserve specific attention. An integrated ASD-ID outpatient clinic contributes to this demand.

Patients with complex rare genetic syndromes (CRGS) have combined medical problems affecting multiple organ systems. Pediatric multidisciplinary (MD) care has improved life expectancy, however, transfer to internal medicine is hindered by the lack of adequate MD care for adults. We have launched an MD outpatient clinic providing syndrome-specific care for adults with CRGS, which, to our knowledge, is the first one worldwide in the field of internal medicine. Between 2015 and 2020, we have treated 720 adults with over 60 syndromes. Eighty-nine percent of the syndromes were associated with endocrine problems. We describe case series of missed diagnoses and patients who had undergone extensive diagnostic testing for symptoms that could actually be explained by their syndrome. Based on our experiences and review of the literature, we provide an algorithm for the clinical approach of health problems in CRGS adults. We conclude that missed diagnoses and needless invasive tests seem common in CRGS adults. Due to the increased life expectancy, an increasing number of patients with CRGS will transfer to adult endocrinology. Internist-endocrinologists (in training) should be aware of their special needs and medical pitfalls of CRGS will help prevent the burden of unnecessary diagnostics and under- and overtreatment.

Prader-Willi syndrome (PWS) is a complex hypothalamic disorder. Features of PWS include hyperphagia, hypotonia, intellectual disability, and pituitary hormone deficiencies. The combination of growth hormone treatment and multidisciplinary care (GHMDc) has greatly improved the health of children with PWS. Little is known about the effects of childhood GHMDc on health outcomes in adulthood. We retrospectively collected clinical data of 109 adults with PWS. Thirty-nine had received GHMDc during childhood and adolescence (GHMDc+ group) and sixty-three had never received growth hormone treatment (GHt) nor multidisciplinary care (GHMDc− group). Our systematic screening revealed fewer undetected health problems in the GHMDc+ group (10%) than in the GHMDc− group (84%). All health problems revealed in the GHMDc+ group had developed between the last visit to the paediatric and the first visit to the adult clinic and/or did not require treatment. Mean BMI and the prevalence of diabetes mellitus type 2 were significantly lower in the GHMDc+ group compared to the GHMDc− group. As all patients who received GHt were treated in a multidisciplinary setting, it is unknown which effects are the result of GHt and which are the result of multidisciplinary care. However, our data clearly show that the combination of both has beneficial effects. Therefore, we recommend continuing GHMDc after patients with PWS have reached adult age.

Smith-Kingsmore syndrome (SKS) is a rare neurodevelopmental disorder characterized by macrocephaly/megalencephaly, developmental delay, intellectual disability, hypotonia, and seizures. It is caused by dominant missense mutations in MTOR. The pathogenicity of novel variants in MTOR in patients with neurodevelopmental disorders can be difficult to determine and the mechanism by which variants cause disease remains poorly understood. We report 7 patients with SKS with 4 novel MTOR variants and describe their phenotypes. We perform in vitro functional analyses to confirm MTOR activation and interrogate disease mechanisms. We complete structural analyses to understand the 3D properties of pathogenic variants. We examine the accuracy of relative accessible surface area, a quantitative measure of amino acid side-chain accessibility, as a predictor of MTOR variant pathogenicity. We describe novel clinical features of patients with SKS. We confirm MTOR Complex 1 activation and identify MTOR Complex 2 activation as a new potential mechanism of disease in SKS. We find that pathogenic MTOR variants disproportionately cluster in hotspots in the core of the protein, where they disrupt alpha helix packing due to the insertion of bulky amino acid side chains. We find that relative accessible surface area is significantly lower for SKS-associated variants compared to benign variants. We expand the phenotype of SKS and demonstrate that additional pathways of activation may contribute to disease. Incorporating 3D properties of MTOR variants may help in pathogenicity classification. We hope these findings may contribute to improving the precision of care and therapeutic development for individuals with SKS., Author summary Smith-Kingsmore Syndrome is a rare disease caused by damage in a gene named MTOR that is associated with excessive growth of the head and brain, delays in development and deficits in intellectual functioning. We report 7 patients who have changes in MTOR that have never been reported before. We describe new medical findings in these patients that may be common in Smith-Kingsmore Syndrome more broadly. We then identify how these new gene changes impact the function of the MTOR protein and thus cell function downstream. Lastly, we show that changes in the gene that lie deep inside the 3D structure of the MTOR protein are more likely to cause disease than those changes that lie on the surface of the protein. We may be able to use the 3D properties of MTOR gene changes to predict if future changes we see are likely to cause disease or not.

Whereas large-scale statistical analyses can robustly identify disease-gene relationships, they do not accurately capture genotype-phenotype correlations or disease mechanisms. We use multiple lines of independent evidence to show that different variant types in a single gene, SATB1, cause clinically overlapping but distinct neurodevelopmental disorders. Clinical evaluation of 42 individuals carrying SATB1 variants identified overt genotype-phenotype relationships, associated with different pathophysiological mechanisms, established by functional assays. Missense variants in the CUT1 and CUT2 DNA-binding domains result in stronger chromatin binding, increased transcriptional repression and a severe phenotype. Contrastingly, variants predicted to result in haploinsufficiency are associated with a milder clinical presentation. A similarly mild phenotype is observed for individuals with premature protein truncating variants that escape nonsense-mediated decay and encode truncated proteins, which are transcriptionally active but mislocalized in the cell. Our results suggest that in-depth mutation-specific genotype-phenotype studies are essential to capture full disease complexity and to explain phenotypic variability.

Mutations in the X-linked gene coding for the calcium-/calmodulin-dependent serine protein kinase (CASK) are associated with severe neurological disorders ranging from intellectual disability (in males) to mental retardation and microcephaly with pontine and cerebellar hypoplasia. CASK is involved in transcription control, in the regulation of trafficking of the post-synaptic NMDA and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, and acts as a presynaptic scaffolding protein. For CASK missense mutations, it is mostly unclear which of CASK's molecular interactions and cellular functions are altered and contribute to patient phenotypes. We identified five CASK missense mutations in male patients affected by neurodevelopmental disorders. These and five previously reported mutations were systematically analysed with respect to interaction with CASK interaction partners by co-expression and co-immunoprecipitation. We show that one mutation in the L27 domain interferes with binding to synapse-associated protein of 97 kDa. Two mutations in the guanylate kinase (GK) domain affect binding of CASK to the nuclear factors CASK-interacting nucleosome assembly protein (CINAP) and T-box, brain, 1 (Tbr1). A total of five mutations in GK as well as PSD-95/discs large/ZO-1 (PDZ) domains affect binding of CASK to the pre-synaptic cell adhesion molecule Neurexin. Upon expression in neurons, we observe that binding to Neurexin is not required for pre-synaptic localization of CASK. We show by bimolecular fluorescence complementation assay that Neurexin induces oligomerization of CASK, and that mutations in GK and PDZ domains interfere with the Neurexin-induced oligomerization of CASK. Our data are supported by molecular modelling, where we observe that the cooperative activity of PDZ, SH3 and GK domains is required for Neurexin binding and oligomerization of CASK.

Introduction: Patients with complex rare genetic syndromes (CRGS) have, by definition, combined medical problems affecting multiple organ systems. Intellectual disability (ID) is often part of the syndrome. During childhood, most patients with CRGS receive multidisciplinary (MD) and specialized pediatric care in tertiary centers. As improvement of medical care has improved life expectancy, more and more patients are now reaching adult age. While the complexity of the syndromes persist into adulthood, adequate multidisciplinary syndrome-specific care is rarely available for adults with CRGS. Although multiple organ systems are usually affected, internists are rarely involved. Pediatricians have expressed the urgent need for adequate, syndrome-specific, MD tertiary healthcare for adults with CRGS. Methods: In 2015 we have launched the Center for Adults with CRGS, a specialized MD outpatient clinic (MOPC) within the Endocrinology unit of the department of Internal Medicine. As adult manifestations are unknown for most CRGS, all CRGS patients who visit our MOPC undergo a systematic health screening (followed by treatment, if indicated). Before visiting the MOPC, caregivers fill out a medical questionnaire. We gathered the physical complaints, medication use and missed diagnoses of 726 adults with CRGS. Results: Between 2015 and 2020, 256 males and 470 females with over 60 syndromes visited the Center for Adults with CRGS. The main features of this population, as compared with general internal medicine patients, were intellectual disability, polypharmacy and use of psychotropic drugs. Missed diagnoses were common and many patients had undergone extensive diagnostic tests for symptoms that could actually be explained by their syndrome. Fatigue (52%), abdominal discomfort (23%) and hypertension (10%) were among the most frequent reasons for referral to Internal Medicine. Based on the literature and our clinical findings, 73% of the syndromes was associated with endocrine problems. We provide an algorithm for the clinical approach to CRGS adults, in order to prevent unnecessary diagnostics as well as missed diagnoses. Conclusion: Our overview of 726 adults with CRGS shows that missed diagnosed and needless invasive tests are common in this patient population. As more and more CRGS patients are now reaching adult age and transfer to Internal Medicine, internists and endocrinologists should be aware of the special needs of adults with CRGS and of the medical pitfalls. Knowledge about syndrome-specific health problems and multidisciplinary expert care is crucial to prevent the personal and financial burden of unnecessary diagnostics and under- and overtreatment.

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Context Prader-Willi syndrome (PWS) is a complex hypothalamic disorder, combining hyperphagia, hypotonia, intellectual disability, and pituitary hormone deficiencies. Annual mortality of patients with PWS is high (3%). In half of the patients, the cause of death is obesity related and/or of cardiopulmonary origin. Health problems leading to this increased mortality often remain undetected due to the complexity and rareness of the syndrome. Objective To assess the prevalence of health problems in adults with PWS retrospectively. Patients, Design, and Setting We systematically screened 115 PWS adults for undiagnosed health problems. All patients visited the multidisciplinary outpatient clinic for rare endocrine syndromes at the Erasmus University Medical Center, Rotterdam, Netherlands. We collected the results of medical questionnaires, interviews, physical examinations, biochemical measurements, polygraphy, polysomnography, and radiology. Main outcome measures Presence or absence of endocrine and nonendocrine comorbidities in relation to living situation, body mass index, genotype, and demographic factors. Results Seventy patients (61%) had undiagnosed health problems, while 1 in every 4 patients had multiple undiagnosed health problems simultaneously. All males and 93% of females had hypogonadism, 74% had scoliosis, 18% had hypertension, 19% had hypercholesterolemia, 17% had type 2 diabetes mellitus, and 17% had hypothyroidism. Unfavorable lifestyles were common: 22% exercised too little (according to PWS criteria) and 37% did not see a dietitian. Conclusions Systematic screening revealed many undiagnosed health problems in PWS adults. Based on patient characteristics, we provide an algorithm for diagnostics and treatment, with the aim to prevent early complications and reduce mortality in this vulnerable patient group.

Crigler-Najjar syndrome presents as severe unconjugated hyper-bilirubinemia and is characteristically caused by a mutation in the UGT1A1 gene, encoding the enzyme responsible for bilirubin glucuronidation. Here we present a patient with Crigler-Najjar syndrome with a completely normal UGT1A1 coding region. Instead, a homozygous 3 nucleotide insertion in the UGT1A1 promoter was identified that interrupts the HNF1 alpha binding site. This mutation results in almost complete abolishment of UGT1A1 promoter activity and prevents the induction of UGT1A1 expression by the liver nuclear receptors CAR and PXR, explaining the lack of a phenobarbital response in this patient. Although animal studies have revealed the importance of HNF1 alpha for normal liver function, this case provides the first clinical proof that mutations in its binding site indeed result in severe liver pathology stressing the importance of promoter sequence analysis. (C) 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Predictive genetic testing for familial adenomatous polyposis (FAP) is routinely offered to children at-risk from the age of 10 years onwards. Predictive testing for FAP at a younger age is debatable, because of absence of medical benefits. However, circumstances may arise when testing at a younger age (< 10 years) is appropriate. Currently, there is a lack of published experience with predictive testing of children at this young age. We evaluated 13 children who were tested for FAP at the age younger than 10 years; 7 mutation-carriers and 6 non-carriers. Parents of these children were re-contacted and open-ended semi-structured interviewed. None of the contacted parents regretted the timing of genetic testing. The major reasons for testing at the young age were (1) testing of all children in the family at the same moment; (2) certainty for the future; and (3) preparing the child for future surveillance. None of the parents observed changes in mental or physical health in their child after testing. Also, young genetic testing did not lead to colon surveillance before it was indicated. Genetic testing for FAP at a young age is experienced as causing no harm by parents. Future studies should evaluate children's own experiences with early genetic testing.

Mutations in WDR62 are associated with primary microcephaly; however, they have been reported with wide phenotypic variability. We report on six individuals with novel WDR62 mutations who illustrate this variability and describe three in greater detail. Of the three, one lacks neuromotor development and has severe pachygyria on MRI, another has only delayed speech and motor development and moderate polymicrogyria, and the third has an intermediate phenotype. Weobserved a rare copy number change of unknown significance, a 17q25qter duplication, in the first severely affected individual. The 17q25 duplication included an interesting candidate gene, tubulin cofactor D (TBCD), crucial in microtubule assembly and disassembly. Sequencing of the non-duplicated allele showed a TBCD missense mutation, predicted to cause a deleterious p. Phe1121Val substitution. Sequencing of a cohort of five patients with WDR62 mutations, including one with an identical mutation and different phenotype, plus 12 individuals with diagnosis of microlissencephaly and another individual with mild intellectual disability (ID) and a 17q25 duplication, did not reveal TBCD mutations. However, immunostaining with tubulin antibodies of cells from patients with both WDR62 and TBCD mutation showed abnormal tubulin network when compared to controls and cells with only the WDR62 mutation. Therefore, we propose that genetic factors contribute to modify the severity of the WDR62 phenotype and, although based on suggestive evidence, TBCD could function as one of such factors. (C) 2014 Wiley Periodicals, Inc.

Objective: Desmoid tumours are rare mesenchymal tumours with unpredictable progression and high recurrence risk. They can occur sporadically or in association with Familial Adenomatous Polyposis (FAP), which is caused by germline APC mutations. The Wnt/beta-catenin pathway has a central role in the pathogenesis of desmoid tumours. These tumours can occur due to either a somatic CTNNB1 or APC mutation but can also be the first manifestation of FAP. Because germline APC analysis is not routinely performed in children with desmoid tumours, the diagnosis FAP may escape detection. The aim of this study is to form guidelines for the identification of possible APC germline mutation carriers among children with desmoid tumours, based on CTNNB1 mutation analysis and immunohistochemical analysis (IHC) for beta-catenin. Patients and methods: We performed IHC of beta-catenin and mutation analysis of CTNNB1 and APC in 18 paediatric desmoid tumours, diagnosed between 1990 and 2009 in the Erasmus MC, Rotterdam. Results: In 11 tumours, IHC showed an abnormal nuclear beta-catenin accumulation. In this group a CTNNB1 mutation was detected in seven tumours. In two tumours with an abnormal nuclear beta-catenin accumulation and no CTNNB1 mutation, an APC mutation was identified, which appeared to be a germline mutation. Conclusions: Aberrant staining of beta-catenin in paediatric desmoids helps to identify children at risk for FAP. We recommend to screen paediatric desmoid tumours for nuclear localisation of beta-catenin and consequently for CTNNB1 mutations. For patients with nuclear beta-catenin expression and no CTNNB1 mutations, APC mutation analysis should be offered after genetic counselling. (C) 2012 Elsevier Ltd. All rights reserved.

Familiaire adenomateuze polyposis coli (FAP) is een erfelijke aandoening die gepaard gaat met het ontstaan van honderden tot duizenden darmpoliepen en darmkanker, veroorzaakt door kiembaanmutaties in het APC-gen. Vaak ontstaan poliepen al op de kinderleeftijd en zijn asymptomatisch of geven aspecifieke klachten. Op de kinderleeftijd kan FAP zich echter ook presenteren met extraintestinale verschijnselen. Hier beschrijven we het beloop, de genetische diagnostiek en counseling bij een kind met hepatoblastoom als de eerste uiting van FAP. Vervolgens wordt een overzicht van de medische, genetische en psychosociale aspecten van FAP op de kinderleeftijd gegeven. Het genetisch testen en counseling van ouders en kinderen in verband met FAP vereist specifieke expertise en dient plaats te vinden in een multidisciplinaire setting.