Risk of meningomyelocele mediated by the common 22q11.2 deletion.

Meningomyelocele is one of the most severe forms of neural tube defects (NTDs) and the most frequent structural birth defect of the central nervous system. We assembled the Spina Bifida Sequencing Consortium to identify causes. Exome and genome sequencing of 715 parent-offspring trios identified six patients with chromosomal 22q11.2 deletions, suggesting a 23-fold increased risk compared with the general population. Furthermore, analysis of a separate 22q11.2 deletion cohort suggested a 12- to 15-fold increased NTD risk of meningomyelocele. The loss of Crkl, one of several neural tube-expressed genes within the minimal deletion interval, was sufficient to replicate NTDs in mice, where both penetrance and expressivity were exacerbated by maternal folate deficiency. Thus, the common 22q11.2 deletion confers substantial meningomyelocele risk, which is partially alleviated by folate supplementation.

Clinical, genetic, and cognitive correlates of seizure occurrences in Phelan-McDermid syndrome.

BACKGROUND: Phelan-McDermid syndrome (PMS) is a genetic neurodevelopmental disorder caused by SHANK3 haploinsufficiency and is associated with an increased risk for seizures. Previous literature indicates that around one third of individuals with PMS also have epilepsy or seizures, with a wide range of types and ages of onset. Investigating the impact of seizures on intellectual and adaptive functioning for PMS is a primary concern for caregivers and is important to understanding the natural history of this syndrome. METHODS: We report on results from 98 individuals enrolled in a prospective, longitudinal study. We detailed seizure frequency, type, and age of onset, and we analyzed seizure occurrence with best estimate IQ, adaptive functioning, clinical features, and genotype. We conducted multiple linear regression analyses to assess the relationship between the presence of seizures and the Vineland Adaptive Behavior Scale, Second Edition (VABS-II) Adaptive Behavior Composite score and the best estimate full-scale IQ. We also performed Chi-square tests to explore associations between seizure prevalence and genetic groupings. Finally, we performed Chi-square tests and t-tests to explore the relationship between seizures and demographic features, features that manifest in infancy, and medical features. RESULTS: Seizures were present in 41% of the cohort, and age of onset was widely variable. The presence of seizures was associated with significantly lower adaptive and intellectual functioning. Genotype-phenotype analyses were discrepant, with no differences in seizure prevalence across genetic classes, but with more genes included in deletions of participants with 22q13 deletions and seizures compared to those with 22q13 deletions and no seizures. No clinical associations were found between the presence of seizures and sex, history of pre- or neonatal complications, early infancy, or medical features. In this cohort, generalized seizures were associated with developmental regression, which is a top concern for PMS caregivers. CONCLUSIONS: These results begin to eludicate correlates of seizures in individuals with PMS and highlight the importance of early seizure management. Importantly, presence of seizures was associated with adaptive and cognitive functioning. A larger cohort might be able to identify additional associations with medical features. Genetic findings suggest an increased capability to realize genotype-phenotype relationships when deletion size is taken into account.

22q11.2 Deletion Syndrome: Influence of Parental Origin on Clinical Heterogeneity.

22q11.2 deletion syndrome (22q11.2DS) shows significant clinical heterogeneity. This study aimed to explore the association between clinical heterogeneity in 22q11.2DS and the parental origin of the deletion. The parental origin of the deletion was determined for 61 individuals with 22q11.2DS by genotyping DNA microsatellite markers and single-nucleotide polymorphisms (SNPs). Among the 61 individuals, 29 (47.5%) had a maternal origin of the deletion, and 32 (52.5%) a paternal origin. Comparison of the frequency of the main clinical features between individuals with deletions of maternal or paternal origin showed no statistically significant difference. However, Truncus arteriosus, pulmonary atresia, seizures, and scoliosis were only found in patients with deletions of maternal origin. Also, a slight difference in the frequency of other clinical features between groups of maternal or paternal origin was noted, including congenital heart disease, endocrinological alterations, and genitourinary abnormalities, all of them more common in patients with deletions of maternal origin. Although parental origin of the deletion does not seem to contribute to the phenotypic variability of most clinical signs observed in 22q11.2DS, these findings suggest that patients with deletions of maternal origin could have a more severe phenotype. Further studies with larger samples focusing on these specific features could corroborate these findings.

A regulatory variant impacting TBX1 expression contributes to basicranial morphology in Homo sapiens.

Changes in gene regulatory elements play critical roles in human phenotypic divergence. However, identifying the base-pair changes responsible for the distinctive morphology of Homo sapiens remains challenging. Here, we report a noncoding single-nucleotide polymorphism (SNP), rs41298798, as a potential causal variant contributing to the morphology of the skull base and vertebral structures found in Homo sapiens. Screening for differentially regulated genes between Homo sapiens and extinct relatives revealed 13 candidate genes associated with basicranial development, with TBX1, implicated in DiGeorge syndrome, playing a pivotal role. Epigenetic markers and in silico analyses prioritized rs41298798 within a TBX1 intron for functional validation. CRISPR editing revealed that the 41-base-pair region surrounding rs41298798 modulates gene expression at 22q11.21. The derived allele of rs41298798 acts as an allele-specific enhancer mediated by E2F1, resulting in increased TBX1 expression levels compared to the ancestral allele. Tbx1-knockout mice exhibited skull base and vertebral abnormalities similar to those seen in DiGeorge syndrome. Phenotypic differences associated with TBX1 deficiency are observed between Homo sapiens and Neanderthals (Homo neanderthalensis). In conclusion, the regulatory divergence of TBX1 contributes to the formation of skull base and vertebral structures found in Homo sapiens.

Caregiver perspectives on patient-focused drug development for Phelan-McDermid syndrome.

BACKGROUND: Phelan-McDermid syndrome (PMS) is a neurodevelopmental disorder caused by SHANK3 haploinsufficiency with clinical manifestations that can be devastating and profoundly affect quality of life. RESULTS: The Externally Led Patient-Focused Drug Development (EL-PFDD) meeting was an opportunity for families affected by PMS to share with the Food and Drug Administration (FDA) how symptoms impact their lives and how treatments could be most meaningful. The Voice of the Patient report serves as a summary of this meeting to influence upcoming drug development and clinical trials. The purpose of this report is to provide a clinical perspective on the results of the EL-PFDD meeting to amplify the voice of these caregivers to the scientific community. CONCLUSIONS: Caregivers prioritize an improved quality of life for their loved ones characterized by improved cognitive function, improved communication, increased independence, and reduced risk of regression. With these caregiver priorities in mind, this report provides the FDA and the scientific community with a clear understanding of which aspects of PMS should influence the development of future therapeutics.

Trisomy 22 Mosaicism from Prenatal to Postnatal Findings: A Case Series and Systematic Review of the Literature.

BACKGROUND: Among aneuploidies compatible with life, trisomy 22 mosaicism is extremely rare, and only about 25 postnatal and 18 prenatal cases have been described in the literature so far. The condition is mainly characterized by facial and body asymmetry, cardiac heart defects, facial dysmorphisms, growth failure, delayed puberty, and variable degrees of neurodevelopmental delay. PROBLEM: The scattered information regarding the condition and the dearth of data on its natural history and developmental outcomes restrict genetic counseling, particularly in prenatal settings. Moreover, a prompt diagnosis is frequently delayed by the negative selection of trisomic cells in blood, with mosaicism percentage varying among tissues, which often entails the need for further testing. Purpose/topic: The aim of our work is to provide assistance in prenatal and postnatal genetic counseling by systematically delineating the current knowledge of the condition. This entails defining the prenatal and postnatal characteristics of the condition and presenting novel data from three cases, both prenatally and postnatally. Additionally, we report the developmental outcomes observed in two new patients.

Evidence for common mechanisms of pathology between SHANK3 and other genes of Phelan-McDermid syndrome.

Chromosome 22q13.3 deletion (Phelan-McDermid) syndrome (PMS, OMIM 606232) is a rare genetic condition that impacts neurodevelopment. PMS most commonly results from heterozygous contiguous gene deletions that include the SHANK3 gene or likely pathogenic variants of SHANK3 (PMS-SHANK3 related). Rarely, chromosomal rearrangements that spare SHANK3 share the same general phenotype (PMS-SHANK3 unrelated). Very recent human and model system studies of genes that likely contribute to the PMS phenotype point to overlap in gene functions associated with neurodevelopment, synaptic formation, stress/inflammation and regulation of gene expression. In this review of recent findings, we describe the functional overlaps between SHANK3 and six partner genes of 22q13.3 (PLXNB2, BRD1, CELSR1, PHF21B, SULT4A1, and TCF20), which suggest a model that explains the commonality between PMS-SHANK3 related and PMS-SHANK3 unrelated classes of PMS. These genes are likely not the only contributors to neurodevelopmental impairments in the region, but they are the best documented to date. The review provides evidence for the overlapping and likely synergistic contributions of these genes to the PMS phenotype.

Young adults with a 22q11.2 microdeletion and the cost of aging with complexity in a population-based context.

PURPOSE: Information about the impact on the adult health care system is limited for complex rare pediatric diseases, despite their increasing collective prevalence that has paralleled advances in clinical care of children. Within a population-based health care context, we examined costs and multimorbidity in adults with an exemplar of contemporary genetic diagnostics. METHODS: We estimated direct health care costs over an 18-year period for adults with molecularly confirmed 22q11.2 microdeletion (cases) and matched controls (total 60,459 person-years of data) by linking the case cohort to health administrative data for the Ontario population (∼15 million people). We used linear regression to compare the relative ratio (RR) of costs and to identify baseline predictors of higher costs. RESULTS: Total adult (age ≥ 18) health care costs were significantly higher for cases compared with population-based (RR 8.5, 95% CI 6.5-11.1) controls, and involved all health care sectors. At study end, when median age was <30 years, case costs were comparable to population-based individuals aged 72 years, likelihood of being within the top 1st percentile of health care costs for the entire (any age) population was significantly greater for cases than controls (odds ratio [OR], for adults 17.90, 95% CI 7.43-43.14), and just 8 (2.19%) cases had a multimorbidity score of zero (vs 1483 (40.63%) controls). The 22q11.2 microdeletion was a significant predictor of higher overall health care costs after adjustment for baseline variables (RR 6.9, 95% CI 4.6-10.5). CONCLUSION: The findings support the possible extension of integrative models of complex care used in pediatrics to adult medicine and the potential value of genetic diagnostics in adult clinical medicine.

Evaluation of catatonia in autism and severe depression revealing Phelan-McDermid syndrome and tetrahydrobiopterin deficiency.

The authors describe a female in her late twenties, presenting with catatonia and diagnosed with epilepsy, autism spectrum disorder, mild intellectual disability, psychosis, dysthymia, anxiety and bipolar disorder, receiving weekly electroconvulsive therapy (ECT). After testing, findings indicated an interstitial deletion in the 22q13.33 region associated with Phelan-McDermid syndrome. In addition, the patient had low cerebral spinal fluid tetrahydrobiopterin (BH4) levels, suggesting dysfunction in the pterin biosynthetic pathway. As a result, the patient started on sapropterin, a BH4 replacement small molecule. After sapropterin treatment, catatonia improved, and the need for ECT decreased. There was an improvement in her cognitive ability, attention and independence. However, there has been no improvement in seizure frequency.

22q13.33 duplication involving SHANK3 gene: a boy and his mother with "persistent" language and speech sound disorder.

Patients carrying 22q13.33 duplication present variable neurodevelopmental phenotype. Among these, patients with genetic alteration disrupting SHANK3 gene are very rare and they also present neurodevelopmental disorder such as autism spectrum disorder and intellectual disability. The real incidence is unknown because mild and variable phenotype could cause reduction in diagnosed cases. We describe the first case of 22q13.33 microduplication disrupting SHANK3 gene, inherited from mother to son, that presents a "persistent" language and speech sound disorder as main symptom without intellectual disability and autism spectrum disorder. More clinical reports with accurate phenotype description are needed to better define the profile of carriers of this genetic alteration.

Genetics of kidney disorders in Phelan-McDermid syndrome: evidence from 357 registry participants.

BACKGROUND: Phelan-McDermid syndrome (PMS) is a rare genetic disorder caused by SHANK3 pathogenic variants or chromosomal rearrangements affecting the chromosome 22q13 region. Previous research found that kidney disorders, primarily congenital anomalies of the kidney and urinary tract, are common in people with PMS, yet research into candidate genes has been hampered by small study sizes and lack of attention to these problems. METHODS: We used a cohort of 357 people from the Phelan-McDermid Syndrome Foundation International Registry to investigate the prevalence of kidney disorders in PMS using a cross-sectional design and to identify 22q13 genes contributing to these disorders. RESULTS: Kidney disorders reported included vesicoureteral reflux (n = 37), hydronephrosis (n = 36), dysplastic kidneys (n = 19), increased kidney size (n = 19), polycystic kidneys (15 cases), and kidney stones (n = 4). Out of 315 subjects with a 22q13 deletion, 101 (32%) had at least one kidney disorder, while only one out of 42 (2%) individuals with a SHANK3 pathogenic variant had a kidney disorder (increased kidney size). We identified two genomic regions that were significantly associated with having a kidney disorder with the peak associations observed near positions approximately 5 Mb and 400 Kb from the telomere. CONCLUSIONS: The candidate genes for kidney disorders include FBLN1, WNT7B, UPK3A, CELSR1, and PLXNB2. This study demonstrates the utility of patient registries for uncovering genetic contributions to rare diseases. Future work should focus on functional studies for these genes to assess their potential pathogenic contribution to the different subsets of kidney disorders.

Living with and managing seizures among parents of children diagnosed with Phelan-McDermid syndrome: a qualitative study using in-depth interviews.

To describe the experience of parents of children diagnosed with Phelan-McDermid syndrome (PMS) in relation to epileptic seizures and/or convulsions, their daily management and impact on family life. A qualitative descriptive study was conducted. The study included parents of children diagnosed with PMS by a medical specialist. Purposive sampling was used, and data were collected via in-depth interviews. A thematic analysis was performed on the data. This study was conducted according to the Standards for Reporting Qualitative Research. Thirty-two parents were recruited. Four themes were identified: (a) the first epileptic seizure, where the first seizure appears abruptly and unexpectedly; (b) living with seizures, seizures generate high concern about the evolution of the disease and the future of children with PMS; (c) treatment of epileptic seizures, obtaining an adequate treatment is a long process that involves decision making by parents; (d) the impact of epilepsy on the family, where there is a change in the functioning and relationships among family members.  Conclusions: It is necessary to develop programs where parents can discuss treatment decisions with professionals and provide coping strategies for the management of epilepsy and seizures. What is Known: • Children with Phelan-McDermid syndrome may develop epilepsy. Parents receive insufficient information for the management and control of seizures. • Parents describe concerns about the evolution of epilepsy in their children's adulthood, along with the impact of seizures and/or convulsions on their children. What is New: • Epilepsy and seizures force the entire family to adapt their lifestyle and give up activities that can trigger seizures. • Parents pointed out the need to create programs to inform about the benefits and disadvantages of pharmacological treatments in order to improve decision making.

Trisomy 22: First and Second Trimester Cytogenetic Analysis and Phenotypic Presentation in a Series of Seven Cases.

INTRODUCTION: Trisomy 22 is a chromosomal disorder rarely encountered prenatally. Even fewer live births are observed and generally correspond to confined placental mosaic trisomy 22, or even more uncommonly, to true fetal mosaic trisomy 22. CASE PRESENTATION: We examine and describe a series of seven cases of trisomy 22 encountered prenatally in terms of their cytogenetic and phenotypic presentations and discuss their interrelationships along with case management and outcomes. We aimed to identify aspects of prenatal data suggestive of fetal trisomy 22 and to determine whether a prognosis can be established from these factors. CONCLUSION: Our conclusion is that prenatal data elements can provide key elements of information to guide multidisciplinary care and support for the couple and the neonate.

Cat eye syndrome: Clinical, cytogenetics and familial findings in a large cohort of 43 patients highlighting the importance of congenital heart disease and inherited cases.

Cat Eye Syndrome (CES) is a rare genetic disease caused by the presence of a small supernumerary marker chromosome derived from chromosome 22, which results in a partial tetrasomy of 22p-22q11.21. CES is classically defined by association of iris coloboma, anal atresia, and preauricular tags or pits, with high clinical and genetic heterogeneity. We conducted an international retrospective study of patients carrying genomic gain in the 22q11.21 chromosomal region upstream from LCR22-A identified using FISH, MLPA, and/or array-CGH. We report a cohort of 43 CES cases. We highlight that the clinical triad represents no more than 50% of cases. However, only 16% of CES patients presented with the three signs of the triad and 9% not present any of these three signs. We also highlight the importance of other impairments: cardiac anomalies are one of the major signs of CES (51% of cases), and high frequency of intellectual disability (47%). Ocular motility defects (45%), abdominal malformations (44%), ophthalmologic malformations (35%), and genitourinary tract defects (32%) are other frequent clinical features. We observed that sSMC is the most frequent chromosomal anomaly (91%) and we highlight the high prevalence of mosaic cases (40%) and the unexpectedly high prevalence of parental transmission of sSMC (23%). Most often, the transmitting parent has mild or absent features and carries the mosaic marker at a very low rate (<10%). These data allow us to better delineate the clinical phenotype associated with CES, which must be taken into account in the cytogenetic testing for this syndrome. These findings draw attention to the need for genetic counseling and the risk of recurrence.

Metabolic signature of the pathogenic 22q11.2 deletion identifies carriers and provides insight into systemic dysregulation.

Large deletions at chromosome 22q11.2 are known to cause severe clinical conditions collectively known as 22q11.2 deletion syndrome. Notwithstanding the pathogenicity of these deletions, affected individuals are typically diagnosed in late childhood or early adolescence, and little is known of the molecular signaling cascades and biological consequences immediately downstream of the deleted genes. Here, we used targeted metabolomics to compare neonatal dried blood spot samples from 203 individuals clinically identified as carriers of a deletion at chromosome 22q11.2 with 203 unaffected individuals. A total of 173 metabolites were successfully identified and used to inform on systemic dysregulation caused by the genomic lesion and to discriminate carriers from non-carriers. We found 84 metabolites to be differentially abundant between carriers and non-carriers of the 22q11.2 deletion. A predictive model based on all 173 metabolites achieved high Accuracy (89%), Area Under the Curve (93%), F1 (88%), Positive Predictive Value (94%), and Negative Predictive Value (84%) with tyrosine and proline having the highest individual contributions to the model as well as the highest interaction strength. Targeted metabolomics provides insight into the molecular consequences possibly contributing to the pathology underlying the clinical manifestations of the 22q11 deletion and is an easily applicable approach to first-pass screening for carrier status of the 22q11 to prompt subsequent verification of the genomic diagnosis.

Gait Abnormalities in Children with Phelan-McDermid Syndrome.

Background: Phelan-McDermid syndrome is a genetic disorder caused by haploinsufficiency of the SHANK3 gene on chromosome 22q13.3 and is characterized by autism spectrum disorder, intellectual disability, speech and language abnormalities, hypotonia, and mild dysmorphic features. Early literature in Phelan-McDermid syndrome did not include gait abnormalities as part of the syndrome although recent prospective studies report that the prevalence of gait abnormalities ranges from 55% to 94%. We compared gait abnormalities in individuals with Phelan-McDermid syndrome, idiopathic autism spectrum disorder, and typically developing controls, and explored associations between gait abnormalities, autism spectrum disorder, and intellectual functioning. Method: The study cohort consists of 67 participants between the ages of 3 and 18 years, divided into 3 groups: Phelan-McDermid syndrome (n = 46), idiopathic autism spectrum disorder (n = 11), and typically developing controls (n = 10). Gait was recorded using a video camera and scored across 26 gait features using a "Gait Clinical Observations scale" designed specifically for this study. Results: Gait abnormalities were significantly higher in the Phelan-McDermid syndrome group as compared to idiopathic autism spectrum disorder or typically developing controls. The number of gait abnormalities across groups was also significantly correlated with Intellectual Quotient/Developmental Quotient (IQ/DQ). In analysis of covariance including IQ/DQ, the effect of group was not significant, but the effect of IQ/DQ was significant. Conclusions: Overall differences in gait abnormalities were determined by the degree of intellectual disability, which was significantly higher in Phelan-McDermid syndrome.

Drugs prescribed for Phelan-McDermid syndrome differentially impact sensory behaviors in shank3 zebrafish models.

Background: Altered sensory processing is a pervasive symptom in individuals with Autism Spectrum Disorders (ASD); people with Phelan McDermid syndrome (PMS), in particular, show reduced responses to sensory stimuli. PMS is caused by deletions of the terminal end of chromosome 22 or point mutations in Shank3. People with PMS can present with an array of symptoms including ASD, epilepsy, gastrointestinal distress, and reduced responses to sensory stimuli. People with PMS are often medicated to manage behaviors like aggression and/or self-harm and/or epilepsy, and it remains unclear how these medications might impact perception/sensory processing. Here we test this using zebrafish mutant shank3ab PMS models that likewise show reduced sensory responses in a visual motor response (VMR) assay, in which increased locomotion is triggered by light to dark transitions. Methods: We screened three medications, risperidone, lithium chloride (LiCl), and carbamazepine (CBZ), prescribed to people with PMS and one drug, 2-methyl-6-(phenylethynyl) pyridine (MPEP) tested in rodent models of PMS, for their effects on a sensory-induced behavior in two zebrafish PMS models with frameshift mutations in either the N- or C- termini. To test how pharmacological treatments affect the VMR, we exposed larvae to selected drugs for 24 hours and then quantified their locomotion during four ten-minute cycles of lights on-to-off stimuli. Results: We found that risperidone normalized the VMR in shank3 models. LiCl and CBZ had no effect on the VMR in any of the three genotypes. MPEP reduced the VMR in wildtype (WT) to levels seen in shank3 models but caused no changes in either shank3 model. Finally, shank3 mutants showed resistance to the seizure-inducing drug pentylenetetrazol (PTZ), at a dosage that results in hyperactive swimming in WT zebrafish. Conclusions: Our work shows that the effects of drugs on sensory processing are varied in ways that can be highly genotype- and drug-dependent.

Ileal Dysbiosis Is Associated with Increased Acoustic Startle in the 22q11.2 Microdeletion Mouse Model of Schizophrenia.

Recent studies involving transplantation of feces from schizophrenia (SCZ) patients and their healthy controls into germ-free mice have demonstrated that the gut microbiome plays a critical role in mediating SCZ-linked physiology and behavior. To date, only one animal model (a metabotropic glutamate receptor 5 knockout) of SCZ has been reported to recapitulate SCZ-linked gut dysbiosis. Since human 22q11.2 microdeletion syndrome is associated with increased risk of SCZ, we investigated whether the 22q11.2 microdeletion ("Q22") mouse model of SCZ exhibits both SCZ-linked behaviors and intestinal dysbiosis. We demonstrated that Q22 mice display increased acoustic startle response and ileal (but not colonic) dysbiosis, which may be due to the role of the ileum as an intestinal region with high immune and neuroimmune activity. We additionally identified a negative correlation between the abundance of a Streptococcus species in the ilea of Q22 mice and their acoustic startle response, providing early evidence of a gut-brain relationship in these mice. Given the translational relevance of this mouse model, our work suggests that Q22 mice could have considerable utility in preclinical research probing the relationship between gut dysbiosis and the gut-brain axis in the pathogenesis of SCZ.

Balanced chromosomal rearrangements implicate YIPF5 and SPATC1L in non-obstructive oligoasthenozoospermia and oligozoospermia and of a derivative chromosome 22 in recurrent miscarriage.

Naturally occurring balanced, unbalanced, and complex chromosomal rearrangements have been reported to cause pathogenic genomic or genetic variants leading to infertility and recurrent miscarriage. Therefore, balanced chromosomal rearrangements were used as genomic signposts for identification of candidate genes or genomic loci associated with male infertility due to defects of spermatogenesis, or with recurrent miscarriage. In three male probands, structural chromosomal variants and copy number variants were identified at nucleotide resolution by long-insert genome sequencing approaches and Sanger sequencing. The pathogenic potential of these and affected candidate genes was assessed based on convergent genomic and genotype-phenotype correlation data. Identification of balanced chromosomal rearrangement breakpoints and interpretation in the context of their genomic background of structural and copy number variants led us to conclude that the infertility due to oligoasthenozoospermia and oligozoospermia is most likely associated with a position effect on YIPF5 and SPATC1L, respectively. In a third proband with intellectual disability and recurrent miscarriage, disruption of CAMK2B causing autosomal dominant, intellectual developmental disorder 54 and increased meiotic segregation during gametogenesis of a der(22) are responsible for the reported phenotype. Our data further support the existence of loci at 5q23 and 21q22.3 for these spermatogenesis defects and highlight the importance of the naturally occurring balanced chromosomal rearrangements for assessment of the pathogenic mechanisms. Furthermore, we show comorbidities due to the same balanced chromosomal rearrangement caused by different pathogenic mechanisms.

Updated consensus guidelines on the management of Phelan-McDermid syndrome.

Phelan-McDermid syndrome (PMS) is a genetic condition caused by SHANK3 haploinsufficiency and characterized by a wide range of neurodevelopmental and systemic manifestations. The first practice parameters for assessment and monitoring in individuals with PMS were published in 2014; recently, knowledge about PMS has grown significantly based on data from longitudinal phenotyping studies and large-scale genotype-phenotype investigations. The objective of these updated clinical management guidelines was to: (1) reflect the latest in knowledge in PMS and (2) provide guidance for clinicians, researchers, and the general community. A taskforce was established with clinical experts in PMS and representatives from the parent community. Experts joined subgroups based on their areas of specialty, including genetics, neurology, neurodevelopment, gastroenterology, primary care, physiatry, nephrology, endocrinology, cardiology, gynecology, and dentistry. Taskforce members convened regularly between 2021 and 2022 and produced specialty-specific guidelines based on iterative feedback and discussion. Taskforce leaders then established consensus within their respective specialty group and harmonized the guidelines. The knowledge gained over the past decade allows for improved guidelines to assess and monitor individuals with PMS. Since there is limited evidence specific to PMS, intervention mostly follows general guidelines for treating individuals with developmental disorders. Significant evidence has been amassed to guide the management of comorbid neuropsychiatric conditions in PMS, albeit mainly from caregiver report and the experience of clinical experts. These updated consensus guidelines on the management of PMS represent an advance for the field and will improve care in the community. Several areas for future research are also highlighted and will contribute to subsequent updates with more refined and specific recommendations as new knowledge accumulates.