PLS3 missense variants affecting the actin-binding domains cause X-linked congenital diaphragmatic hernia and body-wall defects.

Congenital diaphragmatic hernia (CDH) is a relatively common and genetically heterogeneous structural birth defect associated with high mortality and morbidity. We describe eight unrelated families with an X-linked condition characterized by diaphragm defects, variable anterior body-wall anomalies, and/or facial dysmorphism. Using linkage analysis and exome or genome sequencing, we found that missense variants in plastin 3 (PLS3), a gene encoding an actin bundling protein, co-segregate with disease in all families. Loss-of-function variants in PLS3 have been previously associated with X-linked osteoporosis (MIM: 300910), so we used in silico protein modeling and a mouse model to address these seemingly disparate clinical phenotypes. The missense variants in individuals with CDH are located within the actin-binding domains of the protein but are not predicted to affect protein structure, whereas the variants in individuals with osteoporosis are predicted to result in loss of function. A mouse knockin model of a variant identified in one of the CDH-affected families, c.1497G>C (p.Trp499Cys), shows partial perinatal lethality and recapitulates the key findings of the human phenotype, including diaphragm and abdominal-wall defects. Both the mouse model and one adult human male with a CDH-associated PLS3 variant were observed to have increased rather than decreased bone mineral density. Together, these clinical and functional data in humans and mice reveal that specific missense variants affecting the actin-binding domains of PLS3 might have a gain-of-function effect and cause a Mendelian congenital disorder.

Frequency of QTc Interval Prolongation in Children and Adults with Williams Syndrome.

QTc prolongation (≥ 460 ms), according to Bazett formula (QTcB), has been identified to be increased in Williams syndrome (WS) and suggested as a potential cause of increased risk of sudden cardiac death. The Bazett formula tends to overestimate QTc in higher heart rates. We performed a retrospective chart review of WS patients with ≥ 1 electrocardiogram (EKG) with sinus rhythm, no evidence of bundle branch blocks, and measurable intervals. A total of 280 EKGs from 147 patients with WS were analyzed and 123 EKGs from 123 controls. The QTc was calculated using Bazett formula. The average QTcB for individuals with WS and controls was 444 ± 24 ms and 417 ± 26 ms, respectively (p < 0.001). In our WS cohort 34.4% had at least 1 EKG with a QTcB ≥ 460 ms. The mean heart rate (HR) from patients with WS was significantly higher than controls (96 bpm vs 76 bpm, p < 0.001). Linear regression showed that HR contributed 27% to QTcB prolongation in the patients with WS. Patients with WS have a mean QTcB in the normal range but higher than controls, and a higher than expected frequency of QTc ≥ 460 ms compared to the general population. HR is also higher in WS and contributes modestly to the WS QTcB prolongation. Future studies are needed to assess if these findings contribute risk to sudden cardiac death but in the interim we recommend routine EKG testing, especially when starting QTc prolonging medications.

Social, neurodevelopmental, endocrine, and head size differences associated with atypical deletions in Williams-Beuren syndrome.

Williams-Beuren syndrome (WBS) is a multisystem disorder caused by a hemizygous deletion on 7q11.23 encompassing 26-28 genes. An estimated 2-5% of patients have "atypical" deletions, which extend in the centromeric and/or telomeric direction from the WBS critical region. To elucidate clinical differentiators among these deletion types, we evaluated 10 individuals with atypical deletions in our cohort and 17 individuals with similarly classified deletions previously described in the literature. Larger deletions in either direction often led to more severe developmental delays, while deletions containing MAGI2 were associated with infantile spasms and seizures in patients. In addition, head size was notably smaller in those with centromeric deletions including AUTS2. Because children with atypical deletions were noted to be less socially engaged, we additionally sought to determine how atypical deletions relate to social phenotypes. Using the Social Responsiveness Scale-2, raters scored individuals with atypical deletions as having different social characteristics to those with typical WBS deletions (p = .001), with higher (more impaired) scores for social motivation (p = .005) in the atypical deletion group. In recognizing these distinctions, physicians can better identify patients, including those who may already carry a clinical or FISH WBS diagnosis, who may benefit from additional molecular evaluation, screening, and therapy. In addition to the clinical findings, we note mild endocrine findings distinct from those typically seen in WBS in several patients with telomeric deletions that included POR. Further study in additional telomeric deletion cases will be needed to confirm this observation.

Glucose and lipid metabolism, bone density, and body composition in individuals with Williams syndrome.

OBJECTIVE: We assessed body composition, bone mineral density (BMD), glucose and lipids in Williams syndrome (WS), a rare microdeletion disorder. DESIGN: Individuals with WS had outpatient assessment at Massachusetts General Hospital. Controls were selected from the National Health and Nutrition Examination Survey (NHANES 2005-2006). PATIENTS: A total of 22 individuals with WS, each matched by age, sex and race to four NHANES controls. MEASUREMENTS: Blood sampling, oral glucose tolerance test, dual-energy X-ray absorptiometry scan. RESULTS: WS and control groups were 59% female and 29 ± 8 years old. Compared to controls, individuals with WS were shorter but had similar body weight, with more fat and less lean mass. Per cent body fat was higher in WS even after adjusting for BMI (+2.1% [95% CI 0.4, 3.9%]). Four WS patients had abnormal lower extremity fat accumulation resembling lipedema. HbA1c (+0.5% [0.2, 0.7]) and 2-hour glucose (+68 mg/dL [44, 93]) were higher in WS vs controls, differences which persisted after adjusting for BMI. Fasting glucose was comparable between groups. LDL (-18 mg/dL [-35, -2]) and triglycerides (-45 mg/dL [-87, -2]) were significantly lower in WS. Whole-body BMD was significantly lower (-0.15 g/cm2 [-0.20, -0.11]) in WS, and this remained true controlling for height (-0.06 g/cm2 [-0.11, -0.02]). Vitamin D was <30 ng/mL in 81% of those with WS. CONCLUSIONS: On average, adults with WS have increased fat, decreased lean mass, impaired glucose homeostasis and reduced BMD. Clinical efforts to build muscle and bone mass, and to ensure vitamin D sufficiency, are warranted. Genotype-phenotype research efforts are also warranted.

The proceedings of the 15th professional conference on Williams Syndrome.

Williams Syndrome (WS) is a contiguous gene deletion disorder, caused by the deletion of approximately 26-28 genes from chromosome 7 (7q11.23). Individuals with WS have complex medical, developmental, and behavioral features, requiring multidisciplinary and interdisciplinary collaboration. Guidelines detailing the identification, evaluation, and monitoring of individuals with WS need clarification, especially for primary care providers who are first-line in their management. This report summarizes the proceedings of the 2016 Professional Conference on WS in Columbus, OH. Presentations were directed towards primary care providers and subspecialists, emphasizing evidence-based practices for treating the prevalent medical and behavioral features of WS. Included in this report are findings from a panel of cardiovascular experts discussing three case studies on treatment of hypertension and the use of sedation or anesthesia for non-cardiac procedures. Abstracts from individual expert presenters are included, covering various medical and behavioral topics, and providing updates in management of WS individuals. The following topics were discussed: differences in phenotypes of 7q11.23 deletion versus duplication, growth parameters, endocrine concerns, sleep difficulties, behaviors to monitor, and pharmacological options, the neurodevelopmental profile of WS individuals, and the importance of monitoring medical and behavioral concerns as WS individuals transition to adulthood.

A new diagnosis of Williams-Beuren syndrome in a 49-year-old man with severe bullous emphysema.

Williams-Beuren syndrome (WBS) is a chromosomal microdeletion syndrome typically presenting with intellectual disability, a unique personality, a characteristic facial appearance, and cardiovascular disease. Several clinical features of WBS are thought to be due to haploinsufficiency of elastin (ELN), as the ELN locus is included within the WBS critical region at 7q11.23. Emphysema, a disease attributed to destruction of pulmonary elastic fibers, has been reported in patients without WBS who have pathogenic variants in ELN but only once (in one patient) in WBS. Here we report a second adult WBS patient with emphysema where the diagnosis of WBS was established subsequent to the discovery of severe bullous emphysema. Haploinsufficiency of ELN likely contributed to this pulmonary manifestation of WBS. This case emphasizes the contribution of rare genetic variation in cases of severe emphysema and provides further evidence that emphysema should be considered in patients with WBS who have respiratory symptoms, as it may be under-recognized in this patient population.

Molecular pathogenesis of congenital diaphragmatic hernia revealed by exome sequencing, developmental data, and bioinformatics.

Congenital diaphragmatic hernia (CDH) is a common and severe birth defect. Despite its clinical significance, the genetic and developmental pathways underlying this disorder are incompletely understood. In this study, we report a catalog of variants detected by a whole exome sequencing study on 275 individuals with CDH. Predicted pathogenic variants in genes previously identified in either humans or mice with diaphragm defects are enriched in our CDH cohort compared with 120 size-matched random gene sets. This enrichment was absent in control populations. Variants in these critical genes can be found in up to 30.9% of individuals with CDH. In addition, we filtered variants by using genes derived from regions of recurrent copy number variations in CDH, expression profiles of the developing diaphragm, protein interaction networks expanded from the known CDH-causing genes, and prioritized genes with ultrarare and highly disruptive variants, in 11.3% of CDH patients. These strategies have identified several high priority genes and developmental pathways that likely contribute to the CDH phenotype. These data are valuable for comparison of candidate genes generated from whole exome sequencing of other CDH cohorts or multiplex kindreds and provide ideal candidates for further functional studies. Furthermore, we propose that these genes and pathways will enhance our understanding of the heterogeneous molecular etiology of CDH.

Hypercalcemia in Patients with Williams-Beuren Syndrome.

OBJECTIVE: To evaluate the timing, trajectory, and implications of hypercalcemia in Williams-Beuren syndrome (WBS) through a multicenter retrospective study. STUDY DESIGN: Data on plasma calcium levels from 232 subjects with WBS aged 0-67.1 years were compared with that in controls and also with available normative data. Association testing was used to identify relevant comorbidities. RESULTS: On average, individuals with WBS had higher plasma calcium levels than controls, but 86.7% of values were normal. Nonpediatric laboratories overreport hypercalcemia in small children. When pediatric reference intervals were applied, the occurrence of hypercalcemia dropped by 51% in infants and by 38% in toddlers. Across all ages, 6.1% of the subjects had actionable hypercalcemia. In children, actionable hypercalcemia was seen in those aged 5-25 months. In older individuals, actionable hypercalcemia was often secondary to another disease process. Evidence of dehydration, hypercalciuria, and nephrocalcinosis were common in both groups. Future hypercalcemia could not be reliably predicted by screening calcium levels. A subgroup analysis of 91 subjects found no associations between hypercalcemia and cardiovascular disease, gastrointestinal complaints, or renal anomalies. Analyses of electrogradiography data showed an inverse correlation of calcium concentration with corrected QT interval, but no acute life-threatening events were reported. CONCLUSIONS: Actionable hypercalcemia in patients with WBS occurs infrequently. Although irritability and lethargy were commonly reported, no mortality or acute life-threatening events were associated with hypercalcemia and the only statistically associated morbidities were dehydration, hypercalciuria, and nephrocalcinosis.

Mutations in LRP2, which encodes the multiligand receptor megalin, cause Donnai-Barrow and facio-oculo-acoustico-renal syndromes.

Donnai-Barrow syndrome is associated with agenesis of the corpus callosum, congenital diaphragmatic hernia, facial dysmorphology, ocular anomalies, sensorineural hearing loss and developmental delay. By studying multiplex families, we mapped this disorder to chromosome 2q23.3-31.1 and identified LRP2 mutations in six families with Donnai-Barrow syndrome and one family with facio-oculo-acoustico-renal syndrome. LRP2 encodes megalin, a multiligand uptake receptor that regulates levels of diverse circulating compounds. This work implicates a pathway with potential pharmacological therapeutic targets.

Cellular interference in craniofrontonasal syndrome: males mosaic for mutations in the X-linked EFNB1 gene are more severely affected than true hemizygotes.

Craniofrontonasal syndrome (CFNS), an X-linked disorder caused by loss-of-function mutations of EFNB1, exhibits a paradoxical sex reversal in phenotypic severity: females characteristically have frontonasal dysplasia, craniosynostosis and additional minor malformations, but males are usually more mildly affected with hypertelorism as the only feature. X-inactivation is proposed to explain the more severe outcome in heterozygous females, as this leads to functional mosaicism for cells with differing expression of EPHRIN-B1, generating abnormal tissue boundaries-a process that cannot occur in hemizygous males. Apparently challenging this model, males occasionally present with a more severe female-like CFNS phenotype. We hypothesized that such individuals might be mosaic for EFNB1 mutations and investigated this possibility in multiple tissue samples from six sporadically presenting males. Using denaturing high performance liquid chromatography, massively parallel sequencing and multiplex-ligation-dependent probe amplification (MLPA) to increase sensitivity above standard dideoxy sequencing, we identified mosaic mutations of EFNB1 in all cases, comprising three missense changes, two gene deletions and a novel point mutation within the 5' untranslated region (UTR). Quantification by Pyrosequencing and MLPA demonstrated levels of mutant cells between 15 and 69%. The 5' UTR variant mutates the stop codon of a small upstream open reading frame that, using a dual-luciferase reporter construct, was demonstrated to exacerbate interference with translation of the wild-type protein. These results demonstrate a more severe outcome in mosaic than in constitutionally deficient males in an X-linked dominant disorder and provide further support for the cellular interference mechanism, normally related to X-inactivation in females.

Congenital diaphragmatic hernia candidate genes derived from embryonic transcriptomes.

Congenital diaphragmatic hernia (CDH) is a common (1 in 3,000 live births) major congenital malformation that results in significant morbidity and mortality. The discovery of CDH loci using standard genetic approaches has been hindered by its genetic heterogeneity. We hypothesized that gene expression profiling of developing embryonic diaphragms would help identify genes likely to be associated with diaphragm defects. We generated a time series of whole-transcriptome expression profiles from laser captured embryonic mouse diaphragms at embryonic day (E)11.5 and E12.5 when experimental perturbations lead to CDH phenotypes, and E16.5 when the diaphragm is fully formed. Gene sets defining biologically relevant pathways and temporal expression trends were identified by using a series of bioinformatic algorithms. These developmental sets were then compared with a manually curated list of genes previously shown to cause diaphragm defects in humans and in mouse models. Our integrative filtering strategy identified 27 candidates for CDH. We examined the diaphragms of knockout mice for one of the candidate genes, pre-B-cell leukemia transcription factor 1 (Pbx1), and identified a range of previously undetected diaphragmatic defects. Our study demonstrates the utility of genetic characterization of normal development as an integral part of a disease gene identification and prioritization strategy for CDH, an approach that can be extended to other diseases and developmental anomalies.

Skin findings in Williams syndrome.

Previous examination in a small number of individuals with Williams syndrome (also referred to as Williams-Beuren syndrome) has shown subtly softer skin and reduced deposition of elastin, an elastic matrix protein important in tissue recoil. No quantitative information about skin elasticity in individuals with Williams syndrome is available; nor has there been a complete report of dermatologic findings in this population. To fill this knowledge gap, 94 patients with Williams syndrome aged 7-50 years were recruited as part of the skin and vascular elasticity (WS-SAVE) study. They underwent either a clinical dermatologic assessment by trained dermatologists (2010 WSA family meeting) or measurement of biomechanical properties of the skin with the DermaLab™ suction cup (2012 WSA family meeting). Clinical assessment confirmed that soft skin is common in this population (83%), as is premature graying of the hair (80% of those 20 years or older), while wrinkles (92%), and abnormal scarring (33%) were detected in larger than expected proportions. Biomechanical studies detected statistically significant differences in dP (the pressure required to lift the skin), dT (the time required to raise the skin through a prescribed gradient), VE (viscoelasticity), and E (Young's modulus) relative to matched controls. The RT (retraction time) also trended longer but was not significant. The biomechanical differences noted in these patients did not correlate with the presence of vascular defects also attributable to elastin insufficiency (vascular stiffness, hypertension, and arterial stenosis) suggesting the presence of tissue specific modifiers that modulate the impact of elastin insufficiency in each tissue.

Rapamycin inhibits smooth muscle cell proliferation and obstructive arteriopathy attributable to elastin deficiency.

OBJECTIVE: Patients with elastin deficiency attributable to gene mutation (supravalvular aortic stenosis) or chromosomal microdeletion (Williams syndrome) are characterized by obstructive arteriopathy resulting from excessive smooth muscle cell (SMC) proliferation, mural expansion, and inadequate vessel size. We investigated whether rapamycin, an inhibitor of the cell growth regulator mammalian target of rapamycin (mTOR) and effective against other SMC proliferative disorders, is of therapeutic benefit in experimental models of elastin deficiency. APPROACH AND RESULTS: As previously reported, Eln(-/-) mice demonstrated SMC hyperplasia and severe stenosis of the aorta, whereas Eln(+/-) mice exhibited a smaller diameter aorta with more numerous but thinner elastic lamellae. Increased mTOR signaling was detected in elastin-deficient aortas of newborn pups that was inhibited by maternal administration of rapamycin. mTOR inhibition reduced SMC proliferation and aortic obstruction in Eln(-/-) pups and prevented medial hyperlamellation in Eln(+/-) weanlings without compromising aortic size. However, rapamycin did not prolong the survival of Eln(-/-) pups, and it retarded the somatic growth of juvenile Eln(+/-) and Eln(+/+) mice. In cell cultures, rapamycin inhibited prolonged mTOR activation and enhanced proliferation of SMC derived from patients with supravalvular aortic stenosis and with Williams syndrome. CONCLUSIONS: mTOR inhibition may represent a pharmacological strategy to treat diffuse arteriopathy resulting from elastin deficiency.

Matrisome and Immune Pathways Contribute to Extreme Vascular Outcomes in Williams-Beuren Syndrome.

BACKGROUND: Supravalvar aortic stenosis (SVAS) is a characteristic feature of Williams-Beuren syndrome (WBS). Its severity varies: ~20% of people with Williams-Beuren syndrome have SVAS requiring surgical intervention, whereas ~35% have no appreciable SVAS. The remaining individuals have SVAS of intermediate severity. Little is known about genetic modifiers that contribute to this variability. METHODS AND RESULTS: We performed genome sequencing on 473 individuals with Williams-Beuren syndrome and developed strategies for modifier discovery in this rare disease population. Approaches include extreme phenotyping and nonsynonymous variant prioritization, followed by gene set enrichment and pathway-level association tests. We next used GTEx v8 and proteomic data sets to verify expression of candidate modifiers in relevant tissues. Finally, we evaluated overlap between the genes/pathways identified here and those ascertained through larger aortic disease/trait genome-wide association studies. We show that SVAS severity in Williams-Beuren syndrome is associated with increased frequency of common and rarer variants in matrisome and immune pathways. Two implicated matrisome genes (ACAN and LTBP4) were uniquely expressed in the aorta. Many genes in the identified pathways were previously reported in genome-wide association studies for aneurysm, bicuspid aortic valve, or aortic size. CONCLUSIONS: Smaller sample sizes in rare disease studies necessitate new approaches to detect modifiers. Our strategies identified variation in matrisome and immune pathways that are associated with SVAS severity. These findings suggest that, like other aortopathies, SVAS may be influenced by the balance of synthesis and degradation of matrisome proteins. Leveraging multiomic data and results from larger aorta-focused genome-wide association studies may accelerate modifier discovery for rare aortopathies like SVAS.

Hearing from parents: the impact of receiving the diagnosis of Williams syndrome in their child.

Healthcare providers often share difficult or life-altering news with their patients yet this challenging and delicate process is frequently met with dissatisfaction by those receiving this news. Articles and guidelines exist to aid providers in sharing diagnoses such as Down syndrome, but relatively few have focused on rare genetic conditions often diagnosed years after birth. For this reason, we sought to learn about the experience of receiving a diagnosis from parents of children with Williams syndrome. We asked members of the Williams Syndrome Association to complete an anonymous online survey about recollections related to the diagnostic process. Responses, both close-ended and open-ended, were received from 600 families across the United States. Analysis revealed a high proportion of families (59.91%) with at least some negative recollections about the experience (and nearly half of those with negative recollections denied recalling anything positive). Factors influencing a more positive overall perception of the experience included receiving written information about Williams syndrome and seeing a genetic counselor. Analysis of open-ended responses identified additional positive and negative themes; for example, nearly one quarter of respondents expressed a desire to be given hope when receiving the diagnosis. Based on these analyses, we offer several specific recommendations for improving the diagnostic process in the future.

Mutations in IRF6 cause Van der Woude and popliteal pterygium syndromes.

Interferon regulatory factor 6 (IRF6) belongs to a family of nine transcription factors that share a highly conserved helix-turn-helix DNA-binding domain and a less conserved protein-binding domain. Most IRFs regulate the expression of interferon-alpha and -beta after viral infection, but the function of IRF6 is unknown. The gene encoding IRF6 is located in the critical region for the Van der Woude syndrome (VWS; OMIM 119300) locus at chromosome 1q32-q41 (refs 2,3). The disorder is an autosomal dominant form of cleft lip and palate with lip pits, and is the most common syndromic form of cleft lip or palate. Popliteal pterygium syndrome (PPS; OMIM 119500) is a disorder with a similar orofacial phenotype that also includes skin and genital anomalies. Phenotypic overlap and linkage data suggest that these two disorders are allelic. We found a nonsense mutation in IRF6 in the affected twin of a pair of monozygotic twins who were discordant for VWS. Subsequently, we identified mutations in IRF6 in 45 additional unrelated families affected with VWS and distinct mutations in 13 families affected with PPS. Expression analyses showed high levels of Irf6 mRNA along the medial edge of the fusing palate, tooth buds, hair follicles, genitalia and skin. Our observations demonstrate that haploinsufficiency of IRF6 disrupts orofacial development and are consistent with dominant-negative mutations disturbing development of the skin and genitalia.

Diversity of Participants in Williams Syndrome Intervention Studies.

PURPOSE: This study describes participant diversity in Williams syndrome (WS) intervention studies. METHODS: A literature search was conducted to identify prospective treatment studies including participants with WS. Data was extracted on the reporting of and information provided on age, sex, cognitive ability, socioeconomic status, race, and ethnicity. RESULTS: Eleven eligible articles were identified. Reporting rates of demographic factors varied considerably, with the highest rates for age and sex (100%) and the lowest reporting rates for race (18%) and ethnicity (9%). Combining demographic data from the two studies that reported on race and/or ethnicity (n = 33), 88% of participants were White. The combined participant mean age was 20.9 years. CONCLUSION: There is a low frequency of reporting on several demographic factors including socioeconomic status, race, and ethnicity in WS intervention studies. There is a need for increased representation of racial and ethnic minority groups, older participants, and more cognitively impaired patients in WS research.

Congenital diaphragmatic hernia interval on chromosome 8p23.1 characterized by genetics and protein interaction networks.

Chromosome 8p23.1 is a common hotspot associated with major congenital malformations, including congenital diaphragmatic hernia (CDH) and cardiac defects. We present findings from high-resolution arrays in patients who carry a loss (n = 18) or a gain (n = 1) of sub-band 8p23.1. We confirm a region involved in both diaphragmatic and heart malformations. Results from a novel CNVConnect algorithm, prioritizing protein-protein interactions between products of genes in the 8p23.1 hotspot and products of previously known CDH causing genes, implicated GATA4, NEIL2, and SOX7 in diaphragmatic defects. Sequence analysis of these genes in 226 chromosomally normal CDH patients, as well as in a small number of deletion 8p23.1 patients, showed rare unreported variants in the coding region; these may be contributing to the diaphragmatic phenotype. We also demonstrated that two of these three genes were expressed in the E11.5-12.5 primordial mouse diaphragm, the developmental stage at which CDH is thought to occur. This combination of bioinformatics and expression studies can be applied to other chromosomal hotspots, as well as private microdeletions or microduplications, to identify causative genes and their interaction networks.

Genetic counseling as a tool for type 2 diabetes prevention: a genetic counseling framework for common polygenetic disorders.

Advances in genetic epidemiology have increased understanding of common, polygenic preventable diseases such as type 2 diabetes. As genetic risk testing based on this knowledge moves into clinical practice, we propose that genetic counselors will need to expand their roles and adapt traditional counseling techniques for this new patient set. In this paper, we present a genetic counseling intervention developed for a clinical trial [Genetic Counseling/Lifestyle Change for Diabetes Prevention, ClinicalTrials.gov identifier: NCT01034319] designed to motivate behavioral changes for diabetes prevention. Seventy-two phenotypically high-risk participants received counseling that included their diabetes genetic risk score, general education about diabetes risk factors, and encouragement to participate in a diabetes prevention program. Using two validated genetic counseling scales, participants reported favorable perceived control and satisfaction with the counseling session. Our intervention represents one model for applying traditional genetic counseling principles to risk testing for polygenetic, preventable diseases, such as type 2 diabetes.

Functional Neurological Symptom Disorder in Williams Syndrome: Case Series and Review of Relevant Literature.

BACKGROUND: Williams syndrome (WS) is a neurodevelopmental disorder associated with several medical and psychiatric comorbidities. OBJECTIVE: To describe the clinical presentation and treatment course of functional neurological symptom disorder (FNSD) in 3 adult patients with WS. METHODS: This report describes the clinical presentation and long-term follow-up of 3 individuals with WS and FNSD who experienced a range of clinical presentations and responses to treatment. The literature on the clinical assessment and treatment of FNSD as it applies to patients with neurodevelopmental disorders is reviewed. RESULTS: FNSD treatment strategies used in the general population were successfully adapted for these 3 patients. Literature on the diagnosis and treatment of FNSD in patients with neurodevelopmental disorders is lacking. CONCLUSIONS: FNSD may be more common in individuals with WS than previously appreciated, and future studies describing the prevalence, clinical presentation, risk factors, and treatment of FNSD in WS are needed.