Arianne Stevens Wallace

The Cognitive and Behavioral Phenotype of the 16p11.2 Deletion in a Clinically Ascertained Population

BACKGROUND Deletion of the recurrent ~600 kb BP4-BP5 chromosomal region 16p11.2 has been associated with a wide range of neurodevelopmental outcomes. METHODS To clarify the phenotype of 16p11.2 deletion, we examined the psychiatric and developmental presentation of predominantly clinically referred individuals, with a particular emphasis on broader autism phenotype characteristics in individuals with recurrent ~600 kb chromosome 16p11.2 deletions. Using an extensive standardized assessment battery across three clinical sites, 85 individuals with the 16p11.2 deletion and 153 familial control subjects were evaluated for symptom presentation and clinical diagnosis. RESULTS Individuals with the 16p11.2 deletion presented with a high frequency of psychiatric and developmental disorders (>90%). The most commonly diagnosed conditions were developmental coordination disorder, phonologic processing disorder, expressive and receptive language disorders (71% of individuals >3 years old with a speech and language-related disorder), and autism spectrum disorder. Individuals with the 16p11.2 deletion not meeting diagnostic criteria for autism spectrum disorder had a significantly higher prevalence of autism-related characteristics compared with the familial noncarrier control group. Individuals with the 16p11.2 deletion had a range of intellectual ability, but IQ scores were 26 points lower than noncarrier family members on average. CONCLUSIONS Clinically referred individuals with the 16p11.2 deletion have high rates of psychiatric and developmental disorders and provide a genetically well-defined group to study the emergence of developmental difficulties, particularly associated with the broader autism phenotype.

Clinical phenotype of the recurrent 1q21.1 copy-number variant

Purpose:To characterize the clinical phenotype of the recurrent copy-number variation (CNV) at 1q21.1, we assessed the psychiatric and medical phenotypes of 1q21.1 deletion and duplication carriers ascertained through clinical genetic testing and family member cascade testing, with particular emphasis on dimensional assessment across multiple functional domains.Methods:Nineteen individuals with 1q21.1 deletion, 19 individuals with the duplication, and 23 familial controls (noncarrier siblings and parents) spanning early childhood through adulthood were evaluated for psychiatric, neurologic, and other medical diagnoses, and their cognitive, adaptive, language, motor, and neurologic domains were also assessed. Twenty-eight individuals with 1q21.1 CNVs (15 deletion, 13 duplication) underwent structural magnetic resonance brain imaging.Results:Probands with 1q21.1 CNVs presented with a range of psychiatric, neurologic, and medical disorders. Deletion and duplication carriers shared several features, including borderline cognitive functioning, impaired fine and gross motor functioning, articulation abnormalities, and hypotonia. Increased frequency of Autism Spectrum Disorder (ASD) diagnosis, increased ASD symptom severity, and increased prevalence of macrocephaly were observed in the duplication relative to deletion carriers, whereas reciprocally increased prevalence of microcephaly was observed in the deletion carriers.Conclusions:Individuals with 1q21.1 deletions or duplications exhibit consistent deficits on motor and cognitive functioning and abnormalities in head circumference.Genet Med 18 4, 341–349.

Developmental trajectories for young children with 16p11.2 copy number variation

Copy number variation at 16p11.2 is associated with diverse phenotypes but little is known about the early developmental trajectories and emergence of the phenotype. This longitudinal study followed 56 children with the 16p11.2 BP4‐BP5 deletion or duplication between the ages of 6 months and 8 years with diagnostic characterization and dimensional assessment across cognitive, adaptive, and behavioral domains. Linear mixed modeling revealed distinct developmental trajectories with deletions showing VIQ gains but declines in motor and social abilities while duplications showed VIQ gains and steady development across other domains. Nonparametric analyses suggest distinct trajectories and early cognitive abilities for deletion carriers who are ultimately diagnosed with intellectual disability and developmental coordination disorder as well as distinct trajectories and early social communication and cognitive abilities for duplication carriers diagnosed with ASD and intellectual disability. Findings provide predictions for patient developmental trajectories, insight into mean functioning of individuals with 16p11.2 at early ages, and highlight the need for ongoing monitoring of social and motor functioning and behavioral symptomatology to improve treatment planning.

Prospective investigation of FOXP1 syndrome

BackgroundHaploinsufficiency of the forkhead-box protein P1 (FOXP1) gene leads to a neurodevelopmental disorder termed FOXP1 syndrome. Previous studies in individuals carrying FOXP1 mutations and deletions have described the presence of autism spectrum disorder (ASD) traits, intellectual disability, language impairment, and psychiatric features. The goal of the present study was to comprehensively characterize the genetic and clinical spectrum of FOXP1 syndrome. This is the first study to prospectively examine the genotype-phenotype relationship in multiple individuals with FOXP1 syndrome, using a battery of standardized clinical assessments.MethodsGenetic and clinical data was obtained and analyzed from nine children and adolescents between the ages of 5–17 with mutations in FOXP1. Phenotypic characterization included gold standard ASD testing and norm-referenced measures of cognition, adaptive behavior, language, motor, and visual-motor integration skills. In addition, psychiatric, medical, neurological, and dysmorphology examinations were completed by a multidisciplinary team of clinicians. A comprehensive review of reported cases was also performed. All missense and in-frame mutations were mapped onto the three-dimensional structure of DNA-bound FOXP1.ResultsWe have identified nine de novo mutations, including three frameshift, one nonsense, one mutation in an essential splice site resulting in frameshift and insertion of a premature stop codon, three missense, and one in-frame deletion. Reviewing prior literature, we found seven instances of recurrent mutations and another 34 private mutations. The majority of pathogenic missense and in-frame mutations, including all four missense mutations in our cohort, lie in the DNA-binding domain. Through structural analyses, we show that the mutations perturb amino acids necessary for binding to the DNA or interfere with the domain swapping that mediates FOXP1 dimerization. Individuals with FOXP1 syndrome presented with delays in early motor and language milestones, language impairment (expressive language > receptive language), ASD symptoms, visual-motor integration deficits, and complex psychiatric presentations characterized by anxiety, obsessive-compulsive traits, attention deficits, and externalizing symptoms. Medical features included non-specific structural brain abnormalities and dysmorphic features, endocrine and gastrointestinal problems, sleep disturbances, and sinopulmonary infections.ConclusionsThis study identifies novel FOXP1 mutations associated with FOXP1 syndrome, identifies recurrent mutations, and demonstrates significant clustering of missense mutations in the DNA-binding domain. Clinical findings confirm the role FOXP1 plays in development across multiple domains of functioning. The genetic findings can be incorporated into clinical genetics practice to improve accurate genetic diagnosis of FOXP1 syndrome and the clinical findings can inform monitoring and treatment of individuals with FOXP1 syndrome.

Health-Related Quality of Life in Pediatric Patients With Demyelinating Diseases: Relevance of Disability, Relapsing Presentation, and Fatigue

Objective Decreased health-related quality of life (HRQOL) in pediatric patients with multiple sclerosis is established, but little research has examined HRQOL in the broader pediatric demyelinating disease population, and predictors of reduced HRQOL are largely unexplored. We sought to (1) compare generic HRQOL and fatigue of pediatric patients with relapsing (i.e., multiple sclerosis and neuromyelitis optica) versus monophasic demyelinating diseases (i.e., acute disseminated encephalomyelitis, optic neuritis, transverse myelitis, clinically isolated syndrome) and (2) examine the extent to which disability, relapsing disease, and fatigue predict HRQOL. Methods Child and/or parent-proxy reports of generic and fatigue-related HRQOL were collected for 64 pediatric patients with demyelinating diseases. HRQOL of the sample was compared with published healthy child norms. Independent samples t-tests compared HRQOL and fatigue for children with monophasic versus relapsing diseases. Regression analyses examined disability, disease presentation, and fatigue as potential predictors of HRQOL. Results Compared with healthy child norms, generic HRQOL was significantly lower for the demyelinating disorder group, for both child and parent reports across multiple domains. As hypothesized, the relapsing disease group reported lower overall HRQOL and more fatigue than the monophasic group. Disability and relapsing disease predicted lower HRQOL for both parents and children, whereas fatigue was only predictive per the child perspective. Conclusions Children with demyelinating diseases evidence significantly lower HRQOL than healthy peers, supporting need for intervention. Those with relapsing disease appear particularly at risk; targeting disability and fatigue may be fruitful areas for intervention.

Comorbid symptoms of inattention, autism, and executive cognition in youth with putative genetic risk

BACKGROUND Symptoms of autism spectrum disorder (ASD) and inattention (IA) are highly comorbid and associated with deficits in executive cognition. Cognitive deficits have been posited as candidate endophenotypes of psychiatric traits, but few studies have conceptualized cognitive deficits as psychiatric comorbidities. The latter model is consistent with a latent factor reflecting broader liability to neuropsychological dysfunction, and explains heterogeneity in the cognitive profile of individuals with ASD and IA. METHODS We tested competing models of covariance among symptoms of ASD, IA, and cognition in a sample of 73 youth with a known genetic mutation. RESULTS A common executive factor fit best as a cognitive comorbidity, rather than endophenotype, of the shared variance between measures of IA and ASD symptoms. Known genetic risk explained a third of the shared variance among psychiatric and cognitive measures. CONCLUSIONS Comorbid symptoms of ASD, IA, and cognitive deficits are likely influenced by common neurogenetic factors. Known genetic risk in ASD may inform future investigation of putative genetic causes of IA.

Longitudinal report of child with de novo 16p11.2 triplication

16p11.2 deletions and duplications are commonly associated with autism spectrum disorder and linked to mirrored phenotypes of physical characteristics and higher penetrance for deletions. A male with a rare 16p11.2 triplication demonstrated a similar phenotypic presentation to deletion carriers with neurocognitive and adaptive skill deficits and above‐average physical growth.

Auditory perception is associated with implicit language learning and receptive language ability in autism spectrum disorder

Background: Autism spectrum disorder (ASD) is associated with language impairment as well as atypical auditory sensory processing. The current study investigated associations among auditory perception, implicit language learning and receptive language ability in youth with ASD. Methods: We measured auditory event related potentials (ERP) during an artificial language statistical learning task in 76 youth with ASD and 27 neurotypical (NT) controls. Participants with ASD had a broad range of cognitive and language abilities. Results: NT youth showed evidence of implicit learning via attenuated P1 amplitude in the left hemisphere. In contrast, among youth with ASD, implicit learning elicited bilateral attenuation that was increasingly evident with greater receptive language skill. Conclusions: Efficient early auditory perception reflects language learning and is a marker of language ability among youth with ASD. Atypical lateralization of word learning is evident in ASD across a broad range of receptive language abilities.

The autism spectrum phenotype in ADNP syndrome: Arnett et al./ASD phenotype in ADNP

Pathogenic disruptions to the activity‐dependent neuroprotector homeobox (ADNP) gene are among the most common heterozygous genetic mutations associated with autism spectrum disorders (ASDs). Individuals with ADNP disruptions share a constellation of medical and psychiatric features, including ASD, intellectual disability (ID), dysmorphic features, and hypotonia. However, the profile of ASD symptoms associated with ADNP may differ from that of individuals with another ASD‐associated single gene disruption or with ASD without a known genetic cause. The current study examined the ASD phenotype in a sample of representative youth with ADNP disruptions. Participants (N = 116, ages 4–22 years) included a cohort with ADNP mutations (n = 11) and three comparison groups with either a mutation to CHD8 (n = 11), a mutation to another ASD‐associated gene (other mutation; n = 53), or ASD with no known genetic etiology (idiopathic ASD; n = 41). As expected, individuals with ADNP disruptions had higher rates of ID but less severe social affect symptoms compared to the CHD8 and Idiopathic ASD groups. In addition, verbal intelligence explained more variance in social impairment in the ADNP group compared to CHD8, other mutation, and idiopathic ASD comparison groups. Restricted and repetitive behaviors in the ADNP group were characterized by high levels of stereotyped motor behaviors, whereas the idiopathic ASD group showed high levels of restricted interests. Taken together, these results underscore the role of ADNP in cognitive functioning and suggest that social impairments in ADNP syndrome are consistent with severity of verbal deficits. Autism Res 2018, 11: 1300–1310.