Cornelia de Lange Syndrome: From a Disease to a Broader Spectrum.

Cornelia de Lange syndrome (CdLS) is a genetic disease that exemplifies the evolution of knowledge in the field of rare genetic disorders. Originally described as a unique pattern of major and minor anomalies, over time this syndrome has been shown to be characterized by a significant variability of clinical expression. By increasing the number of patients described, knowledge of the natural history of the condition has been enriched with the demonstration of the relative frequency of various potential comorbidities. Since 2006, the discovery of CdLS's molecular basis has shown an equally vast genetic heterogeneity linked to the presence of variants in genes encoding for the cohesin complex pathway. The most recent clinical-genetic data led to the classification of the "original syndrome" into a "clinical spectrum" that foresees the presence of classic patients, of non-classic forms, and of conditions that show a modest phenotypic overlapping with the original disease. Finally, the knowledge of the molecular basis of the disease has allowed the development of basic research projects that could lay the foundations for the development of possible innovative pharmacological treatments.

Clinical relevance of postzygotic mosaicism in Cornelia de Lange syndrome and purifying selection of NIPBL variants in blood.

Postzygotic mosaicism (PZM) in NIPBL is a strong source of causality for Cornelia de Lange syndrome (CdLS) that can have major clinical implications. Here, we further delineate the role of somatic mosaicism in CdLS by describing a series of 11 unreported patients with mosaic disease-causing variants in NIPBL and performing a retrospective cohort study from a Spanish CdLS diagnostic center. By reviewing the literature and combining our findings with previously published data, we demonstrate a negative selection against somatic deleterious NIPBL variants in blood. Furthermore, the analysis of all reported cases indicates an unusual high prevalence of mosaicism in CdLS, occurring in 13.1% of patients with a positive molecular diagnosis. It is worth noting that most of the affected individuals with mosaicism have a clinical phenotype at least as severe as those with constitutive pathogenic variants. However, the type of genetic change does not vary between germline and somatic events and, even in the presence of mosaicism, missense substitutions are located preferentially within the HEAT repeat domain of NIPBL. In conclusion, the high prevalence of mosaicism in CdLS as well as the disparity in tissue distribution provide a novel orientation for the clinical management and genetic counselling of families.

Customised next-generation sequencing multigene panel to screen a large cohort of individuals with chromatin-related disorder.

BACKGROUND: The regulation of the chromatin state by epigenetic mechanisms plays a central role in gene expression, cell function, and maintenance of cell identity. Hereditary disorders of chromatin regulation are a group of conditions caused by abnormalities of the various components of the epigenetic machinery, namely writers, erasers, readers, and chromatin remodelers. Although neurological dysfunction is almost ubiquitous in these disorders, the constellation of additional features characterizing many of these genes and the emerging clinical overlap among them indicate the existence of a community of syndromes. The introduction of high-throughput next generation sequencing (NGS) methods for testing multiple genes simultaneously is a logical step for the implementation of diagnostics of these disorders. METHODS: We screened a heterogeneous cohort of 263 index patients by an NGS-targeted panel, containing 68 genes associated with more than 40 OMIM entries affecting chromatin function. RESULTS: This strategy allowed us to identify clinically relevant variants in 87 patients (32%), including 30 for which an alternative clinical diagnosis was proposed after sequencing analysis and clinical re-evaluation. CONCLUSION: Our findings indicate that this approach is effective not only in disorders with locus heterogeneity, but also in order to anticipate unexpected misdiagnoses due to clinical overlap among cognate disorders. Finally, this work highlights the utility of a prompt diagnosis in such a clinically and genetically heterogeneous group of disorders that we propose to group under the umbrella term of chromatinopathies.

De novo NIPBL Mutations in Vietnamese Patients with Cornelia de Lange Syndrome.

Cornelia de Lange Syndrome (CdLS) is a rare congenital genetic disease causing abnormal unique facial phenotypes, several defects in organs and body parts, and mental disorder or intellectual disorder traits. Main causes of CdLS have been reported as variants in cohesin complex genes, in which mutations in the NIPBL gene have been estimated to account for up to 80%. Our study included three Vietnamese patients with typical CdLS phenotypes. Whole exome sequencing revealed two known heterozygous mutations c.6697G>A (p.Val2233Met) and c.2602C>T (p.Arg868X), and a novel heterozygous mutation c.4504delG (p.Val1502fsX87) in the NIPBL gene of the three patients. In silico analyses of the identified mutations predicted possible damaging and truncating effects on the NIPBL protein. Inherited analyses in the patients' families showed that all of the mutations are de novo. Our results lead a definitive diagnosis of patients with CdLS and expand the spectrum of mutations in the NIPBL gene. These findings also confirm whole exome sequencing is an efficient tool for genetic screening of CdLS.

Age-related Behavioural Change in Cornelia de Lange and Cri du Chat Syndromes: A Seven Year Follow-up Study.

Age-related behavioural change in Cornelia de Lange syndrome is poorly understood. We report a 7 year follow-up study of adaptive behaviour, autism spectrum disorder symptomatology, language skills and behavioural characteristics in 30 individuals with Cornelia de Lange syndrome, compared with 18 individuals with Cri du Chat syndrome. The proportion of individuals with Cornelia de Lange syndrome meeting criteria for autism spectrum disorder on the Autism Diagnostic Observation Schedule increased, although patterns of change were complex. For both syndrome groups, absolute levels of adaptive ability were stable and receptive language improved, suggesting that changes over time do not result from an overall decline in ability. Reliable change index scores indicate heterogeneity within both groups in the occurrence of improvement or decline.

Cornelia de Lange syndrome in diverse populations.

Cornelia de Lange syndrome (CdLS) is a dominant multisystemic malformation syndrome due to mutations in five genes-NIPBL, SMC1A, HDAC8, SMC3, and RAD21. The characteristic facial dysmorphisms include microcephaly, arched eyebrows, synophrys, short nose with depressed bridge and anteverted nares, long philtrum, thin lips, micrognathia, and hypertrichosis. Most affected individuals have intellectual disability, growth deficiency, and upper limb anomalies. This study looked at individuals from diverse populations with both clinical and molecularly confirmed diagnoses of CdLS by facial analysis technology. Clinical data and images from 246 individuals with CdLS were obtained from 15 countries. This cohort included 49% female patients and ages ranged from infancy to 37 years. Individuals were grouped into ancestry categories of African descent, Asian, Latin American, Middle Eastern, and Caucasian. Across these populations, 14 features showed a statistically significant difference. The most common facial features found in all ancestry groups included synophrys, short nose with anteverted nares, and a long philtrum with thin vermillion of the upper lip. Using facial analysis technology we compared 246 individuals with CdLS to 246 gender/age matched controls and found that sensitivity was equal or greater than 95% for all groups. Specificity was equal or greater than 91%. In conclusion, we present consistent clinical findings from global populations with CdLS while demonstrating how facial analysis technology can be a tool to support accurate diagnoses in the clinical setting. This work, along with prior studies in this arena, will assist in earlier detection, recognition, and treatment of CdLS worldwide.

Attenuated behaviour in Cornelia de Lange and fragile X syndromes.

BACKGROUND: Catatonia-like presentations in people with autism have been increasingly recognised within research and diagnostic guidelines. The recently developed Attenuated Behaviour Questionnaire has identified that attenuated behaviour [autistic catatonia] is very prevalent in people with autism spectrum disorders (ASDs) and associated with repetitive behaviour. In the current study, we investigated attenuated behaviour within two genetic syndromes associated with ASD and examined ASD and repetitive behaviour as longitudinal predictors of attenuated behaviour. METHOD: The Attenuated Behaviour Questionnaire was completed by parents/carers of 33 individuals with Cornelia de Lange syndrome (CdLS) and 69 with fragile X syndrome (FXS). Information collected from the same informants 4 years previously was utilised to examine ASD and repetitive behaviour as predictors of later attenuated behaviour, controlling for age, gender and ability. RESULTS: Catatonia-like attenuated behaviour was reported for individuals with CdLS (30.3%) and FXS (11.6%). Slowed movement was more prevalent in people with CdLS. No other phenotypic differences were observed. Across the two groups, repetitive behaviour predicted the presence of attenuated behaviour 4 years later, after controlling for age, gender and ability. CONCLUSIONS: Attenuated behaviour can be identified in individuals with CdLS and FXS and may have an effect on both adaptive behaviour and quality of life. Repetitive behaviours predicted subsequent risk within both groups and should be assessed by services as part of a pro-active strategy of support.

Síndrome de Cornelia de Lange: incidencia de cardiopatía congénita en 149 pacientes / Cornelia de Lange syndrome: Congenital heart disease in 149 patients

Introducción: El síndrome Cornelia de Lange (SCdL) se produce por afectación de los genes que codifican proteínas reguladoras o estructurales del complejo de cohesinas. La cardiopatía congénita (CC) no es criterio mayor de enfermedad, pero afecta a numerosos individuos. El objetivo de este trabajo ha sido estudiar la incidencia y tipo de CC en pacientes con SCdL. Material y método: Se han evaluado los hallazgos cardiológicos en 149 pacientes con SCdL y su posible relación con variables clínicas y genéticas. Resultados: Un 34,9% presentan CC (defectos septales 50%, estenosis pulmonar 27%, coartación aórtica 9,6%). La presencia de CC se relaciona con hospitalización neonatal (p=0,04), hipoacusia (p=0,002), mortalidad (p=0,09) y menor hiperactividad (p=0,02); es más frecuente en pacientes HDAC8+ (60%), seguido de NIPBL+ (33%) y SMC1A+ (28,5%). Mientras que en NIPBL+ predominan los defectos septales, en HDAC8+ es más frecuente la estenosis pulmonar. Conclusiones: Los pacientes con SCdL tienen una incidencia elevada de CC, que varía según el gen afectado, siendo los hallazgos más frecuentes los defectos septales y la estenosis pulmonar. Se sugiere realizar estudio cardiológico en todos estos pacientes (AU)

Introduction: Cornelia de Lange syndrome (CdLS) is produced by mutations in genes that encode regulatory or structural proteins of the cohesin complex. Congenital heart disease (CHD) is not a major criterion of the disease, but it affects many individuals. The objective of this study was to study the incidence and type of CHD in patients with CdLS. Material and method: Cardiological findings were evaluated in 149 patients with CdLS and their possible relationship with clinical and genetic variables. Results: A percentage of 34.9 had CHD (septal defects 50%, pulmonary stenosis 27%, aortic coarctation 9.6%). The presence of CHD was related with neonatal hospitalisation (P=.04), hearing loss (P=.002), mortality (P=.09) and lower hyperactivity (P=.02), it being more frequent in HDAC8+ patients (60%), followed by NIPBL+ (33%) and SMC1A+ (28.5%). While septal defects predominate in NIPBL+, pulmonary stenosis is more common in HDAC8+. Conclusions: Patients with CdLS have a high incidence of CHD, which varies according to the affected gene, the most frequent findings being septal defects and pulmonary stenosis. Perform a cardiologic study in all these patients is suggested (AU)

Los defectos en las extremidades, una facies peculiar y el fallo de medro no siempre constituyen un síndrome de Cornelia de Lange / Limbs defects, peculiar face and failure to thrive is not always Cornelia de Lange Syndrome

Las malformaciones de las extremidades son raras y su etiología, variable. Existen síndromes genéticos que combinan estas malformaciones con discapacidad intelectual y otras malformaciones graves, como el síndrome de Cornelia de Lange. Presentamos el caso de una paciente con malformaciones severas en las 4 extremidades, discapacidad intelectual y características faciales peculiares que llevaron al diagnóstico presuntivo de síndrome de Cornelia de Lange. Presentamos el caso de una niña de 4 años de edad, padres consanguíneos y etnia gitana, con antecedentes de retraso del crecimiento intrauterino, bajo peso al nacer, microcefalia y múltiples malformaciones en ambas manos y pies, incluida la mano derecha hendida, con diagnóstico presuntivo de síndrome de Cornelia de Lange. Durante el primer año de vida se realizaron varios estudios con los siguientes resultados: cariotipo 46, XX; estudio de deleciones subteloméricas (técnica MLPA) normal; ecocardiograma y electrocardiograma sin hallazgos; evaluación oftalmológica y auditiva normales; ultrasonido abdominal y transfontanelar normales. A los 4 años se le aplicó una técnica de array de hibridación genómica comparada (comparative genomic hybridization) (array-CGH) con resolución de 180 kb, que detectó una deleción causal de 8,4 Mb en la citobanda 2q31.1q31.2. La deleción de 2q31 está asociada a la malformación de mano/pie hendido, y la correlación genotipo-fenotipo indica que las deleciones intersticiales de la región 2q31.1 muestran malformaciones en los miembros si incluyen una región crítica de 2,5 Mb, que incluye el cluster de HOXD y las regiones adyacentes en sentido 5’ y 3’. Concluimos que ante un paciente con malformaciones graves y signos y síntomas superpuestos de varios síndromes, es aconsejable comenzar el plan de trabajo con array-CGH, y si esta técnica no está disponible, realizar un cariotipo de alta resolución con la intención de descartar reordenamientos cromosómicos (AU)

Severe limbs deformities are rare and its etiology is variable. There are known genetic syndromes that combine limbs deformities, mental disability and other mayor malformations, such as Cornelia de Lange syndrome. We present the case of a patient with severe deformities in 4 limbs, mental disability and minor facial features that lead to the presumptive diagnosis of Cornelia de Lange syndrome. Four years old female her parents are consanguineous and from gipsy ethnicity. History of intrauterine growth retardation, low birth weight, microcephaly and multiple deformities in both hands and both feet including split-hand deformity of the right hand. Presumptive diagnosis of Cornelia de Lange syndrome, during the first year of life these studies were performed: kariotype 46, XX, subtelomeric deletion study (MLPA technique): normal, echocardiogram and EKG without abnormalities, oftalmologic and audition evaluation: normal and cranial and abdominal ultrasound also normal. At four years old array comparative genomic hybridization 180 kb was performed and it showed a causal deletion of 8.4 Mb at cytoband 2q31.1q31.2. 2q31 deletion is associated with the split hand/foot malformation, the genotype-phenotype correlation of interstitial deletions of the 2q31.1 region shows that limbs malformation are associated to a critical 2.5 Mb deletion containing the HOXD cluster and surrounding 5’ and 3’ regions. We conclude that when a patient presents major malformations and overlapping signs and symptoms of various syndromes it is wise to begin the workup with high resolution karyotype and/or, where available, array-CGH in order to rule out cytogenetic rearrangements (AU)

Social behavior and characteristics of autism spectrum disorder in Angelman, Cornelia de Lange, and Cri du Chat syndromes.

We evaluated autism spectrum disorder (ASD) characteristics and social behavior in Angelman (AS; n  =  19; mean age  = 10.35 years), Cornelia de Lange (CdLS; n  =  15; mean age  = 12.40 years), and Cri du Chat (CdCS, also known as 5 p-syndrome; n  =  19; mean age  =  8.80 years) syndromes. The proportion of individuals meeting the ASD cutoff on the Social Communication Questionnaire was significantly higher in the AS and CdLS groups than in the CdCS group (p < .01). The groups demonstrated divergent social behavior profiles during social conditions in which adult availability, adult familiarity, and social demand were manipulated. Social enjoyment was significantly heightened in AS, whereas social approaches were heightened in individuals with CdCS. Social motivation, social communication, and enjoyment were significantly lower in CdLS. The findings highlight the importance of detailed observation when evaluating ASD and social behavior in genetic syndromes.

Immunologic features of Cornelia de Lange syndrome.

OBJECTIVES: Cornelia de Lange syndrome (CdLS) is a genetic syndrome with multisystem abnormalities. Infections are a significant cause of morbidity and mortality. The goals of our study were to identify the frequency and types of infections in CdLS and to determine if underlying immunodeficiency contributes to the clinical spectrum of this syndrome. METHODS: We assessed infectious histories in 45 patients with CdLS and evaluated conventional immunologic screening tests in 27 patients. Among these 27 subjects, additional phenotypic enumeration of T-cell subsets, expression of activation markers in T cells, and production of cytokines in response to T-cell stimulants were studied in 12 CdLS subjects compared with 12 normal case control subjects. RESULTS: Recurrent infections were reported at high frequency in CdLS patients and included chronic ear infections (53%), chronic viral respiratory infections (46%), pneumonia (42%), sinus infections (33%), oral candidiasis (13%), sepsis (6%), and bacterial skin infections (4%). Full immune evaluation in 27 subjects led to identification of 9 cases of antibody deficiency syndrome in patients with severe forms of CdLS. Subjects with CdLS had decreased percentages of T regulatory cells and T follicular helper cells compared with normal control subjects (P < .05). CONCLUSIONS: This study identified for the first time a high frequency of antibody deficiency in CdLS subjects, indicating a critical need for screening and management of immunodeficiency in CdLS patients with a history of well-documented severe or recurrent infections. Furthermore, our results indicate that impaired T-cell populations may be associated with antibody deficiency in CdLS.

The prevalence and phenomenology of self-injurious and aggressive behaviour in genetic syndromes.

BACKGROUND: Self-injurious and aggressive behaviours are reported as components of some behavioural phenotypes but there are few studies comparing across syndrome groups. In this study we examined the prevalence of these behaviours and the associated person characteristics in seven genetic syndromes. METHODS: Questionnaire data on self-injury and aggression, mood, hyperactivity, autism spectrum disorder and repetitive behaviour were collected on Angelman (AS, n=104), Cornelia de Lange (CdLS, 101), Cri du Chat (CdCS, 58), Fragile X (FXS, 191), Lowe (LS, 56), Prader-Willi (PWS, 189) and Smith-Magenis (SMS, 42) syndromes. RESULTS: A significantly higher prevalence of self-injury was evident in CdCS, CdLS, FXS, PWS, LS and SMS. The prevalence of aggression was significantly heightened in AS and SMS. Self-injury was associated with repetitive and impulsive behaviour in CdLS, FXS, PWS and LS. Impulsivity and overactivity were significantly higher in those showing aggression across all syndrome groups. CONCLUSIONS: These data quantify the risk for self-injury and aggression in the syndromes studied with implications for early intervention. The associations between these behaviours and person characteristics both within and between syndromes warrant further research.

Characterization of sleep disturbance in Cornelia de Lange Syndrome.

OBJECTIVE: Prior studies have suggested that sleep disturbance is common in Cornelia de Lange Syndrome (CdLS); however, the nature of this sleep disturbance has not been well characterized. In this study, we evaluate the prevalence of sleep disordered breathing (SDB) and sleepiness in children and young adults with CdLS. METHODS: Caregivers of 22 patients with CdLS completed 3 validated Pediatric Sleep Questionnaires: the Pediatric Sleep Questionnaire (PSQ), Pediatric Daytime Sleepiness Scale (PDSS), and OSA18. RESULTS: Both measures of SDB (OSA18 and PSQ) suggest that 35-36% of these patients may have moderate to severe SDB. This is much higher than the general population estimates of 1-4% for SDB with a relative risk of 5.2 (95% CI: 2.8-9.9). Correlation between the OSA18 and PSQ was significant (R=0.67; 95% CI: 0.33-0.85, p=0.0007). Confirming these results among patients with a high probability of SDB (based upon OSA18 scores ≥60), there was a non-significant trend toward increased sleepiness with a relative risk of 2.0 (95% CI: 0.73-5.7, p=0.31) on the PDSS and 2.9 (95% CI: 0.93-9.1, p=0.08) on the PSQ sleepiness scale. In those patients with low probability of SDB (OSA18<60), sleepiness was still seen in 13-29% of patients. Overall 23-35% of participants were characterized as sleepy. CONCLUSIONS: Sleep disordered breathing and sleepiness appear to be common in CdLS although small sample sizes limit further conclusions. Additional studies with larger sample size and confirmation with polysomnography are needed to further explore the nature and extent of sleep disturbance in this population.

Barrett's esophagus and Cornelia de Lange Syndrome.

AIM: To review the records of Cornelia de Lange Syndrome (CDLS) children, affected by Gastro-oesophageal reflux disease (GERD), to detect the presence of Barrett's Esophagus (BE). METHODS: A total of 62 CDLS patients were investigated for GERD (1 month-35 years). In all of them a pH-metry, an upper endoscopy with multiple biopsies and a complete radiologic digestive evaluation were carried out. BE was diagnosed in case of replacement of oesophageal mucosa by specialized intestinal-type columnar mucosa. Anti-reflux surgery was considered in case of persistence of BE after medical therapy. Follow-up (mean 3.5 years) consisted in endoscopy every 6 months . RESULTS: Gastro-oesophageal reflux disease was found in 50 CDLS patients (80%) and BE in six of them (12% of the GERD group, 9.6% of the entire population, mean age 17 years, range 6-32 years). A short segment BE was observed in three patients, a long one in two patients and an infiltrating adenocarcinoma of the lower oesophagus in one patient. CONCLUSIONS: A higher frequency of BE in CDLS patients than in a normal population is found. A delayed diagnosis because of atypical GERD symptoms and an altered intestinal motility as a result of neurological impairment can be recognized as the main cause.

Self-injurious behaviour in Cornelia de Lange syndrome: 2. Association with environmental events.

BACKGROUND: Self-injurious behaviour is commonly seen in Cornelia de Lange syndrome (CdLS). However, there has been limited research into the aetiology of self-injury in CdLS and whether environmental factors influence the behaviour. METHODS: We observed the self-injury of 27 individuals with CdLS and 17 participants who did not have CdLS matched for age, gender, level of intellectual disability and mobility. Descriptive analyses were used to determine the extent to which environmental events were associated with self-injury. RESULTS: Lag sequential analysis of the association between self-injurious behaviour and environmental events revealed no differences between the two groups in terms of either the number or degree of environmental associations. CONCLUSIONS: The results suggest that the associations between the environment and self-injury in CdLS do not differ from those seen in the broader population of people with intellectual disability. By implication the social reinforcement hypothesis is equally applicable to both groups.

Self-injurious behaviour in Cornelia de Lange syndrome: 1. Prevalence and phenomenology.

BACKGROUND: Self-injurious behaviour is frequently identified as part of the behavioural phenotype of Cornelia de Lange syndrome (CdLS). We conducted a case-control study of the prevalence and phenomenology of self-injurious behaviour (SIB) in CdLS. METHODS: A total of 54 participants with CdLS were compared with 46 individuals who were comparable on key variables including age, degree of intellectual disability and wheelchair use, using questionnaire and observational measures. RESULTS: Clinically significant self-injury was not more prevalent in the CdLS group (55.6%), nor was it different in presentation from that seen in the comparison group. Hyperactivity, stereotyped and compulsive behaviours predicted clinically significant self-injury in all participants. Hand directed, mild self-injury was more prevalent in CdLS. CONCLUSIONS: The results show that clinically significant self-injury may not be part of the behavioural phenotype of CdLS but a specific body target for proto-SIB is more common.

[Myopia in systemic disorders]. / Krótkowzrocznosc w schorzeniach ogólnoustrojowych.

Myopia is the most common refractive error Myopia has been well established as a multifactorial disease with both genetic and environmental etiology. A number of genetic loci have been linked with myopia. We have described the prevalence and the symptoms of systemic disorders associated with myopia, including: Stickler syndrome, Marfan syndrome, Ehlers-Danlos syndrome, Weill-Marchesani syndrome, homocystinuria, McCune-Albright syndrome, Kniest syndrome, Down syndrome, Prader-Willi syndrome, Noonan syndrome, Cohen syndrome, Rubinstein-Taybi syndrome, Cornelia de Lange syndrome and fetal alcohol syndrome.

Social anxiety in Cornelia de Lange syndrome.

In this study we assessed the behavioral presentation of social anxiety in Cornelia de Lange syndrome (CdLS) using a contrast group of Cri du Chat syndrome (CdCS). Behaviors indicative of social anxiety were recorded in twelve children with CdLS (mean age = 11.00; SD = 5.15) and twelve children with CdCS (8.20; SD = 2.86) during social interaction. Lag sequential analysis revealed that participants with CdLS were significantly more likely to evidence behavior indicative of anxiety in close temporal proximity to the point at which they maintained eye contact or spoke. Individuals with CdLS demonstrate a heightened probability of anxiety related behavior during social interaction but only at the point at which social demand is high.

The prevalence and phenomenology of repetitive behavior in genetic syndromes.

We investigated the prevalence and phenomenology of repetitive behavior in genetic syndromes to detail profiles of behavior. The Repetitive Behaviour Questionnaire (RBQ) provides fine-grained identification of repetitive behaviors. The RBQ was employed to examine repetitive behavior in Angelman (N = 104), Cornelia de Lange (N = 101), Cri-du-Chat (N = 58), Fragile X (N = 191), Prader-Willi (N = 189), Lowe (N = 56) and Smith-Magenis (N = 42) syndromes and individuals with intellectual disability of heterogeneous aetiology (N = 56). Repetitive behavior was variable across syndromes. Fragile X syndrome scored highly on all subscales. Angelman syndrome demonstrated a significantly lowered probability for most behaviors. Prader-Willi, Cri-du-Chat and Smith-Magenis syndrome evidenced unique profiles of repetitive behavior. There is extreme heterogeneity of repetitive behavior across genetic syndromes, highlighting syndrome specific profiles.

Prevalence of autism spectrum phenomenology in Cornelia de Lange and Cri du Chat syndromes.

Autism spectrum disorder characteristics have not been evaluated in Cornelia de Lange and Cri du Chat syndromes using robust assessments. The Autism Diagnostic Observation Schedule and Social Communication Questionnaire were administered to 34 participants with Cornelia de Lange syndrome and a comparison group of 23 participants with Cri du Chat syndrome (M ages 12.4 [SD = 3.8] and 10.3 years [SD = 3.6], respectively). Twenty-one participants with Cornelia de Lange syndrome (61.8%) scored above the autism cut-off on the Autism Diagnostic Observation Schedule compared to 9 with Cri du Chat syndrome (39.2%). Prevalence of autism spectrum disorder characteristics is heightened in Cornelia de Lange syndrome. The profile of characteristics is atypical to that of idiopathic autism.