Bi-allelic CAMSAP1 variants cause a clinically recognizable neuronal migration disorder.

Non-centrosomal microtubules are essential cytoskeletal filaments that are important for neurite formation, axonal transport, and neuronal migration. They require stabilization by microtubule minus-end-targeting proteins including the CAMSAP family of molecules. Using exome sequencing on samples from five unrelated families, we show that bi-allelic CAMSAP1 loss-of-function variants cause a clinically recognizable, syndromic neuronal migration disorder. The cardinal clinical features of the syndrome include a characteristic craniofacial appearance, primary microcephaly, severe neurodevelopmental delay, cortical visual impairment, and seizures. The neuroradiological phenotype comprises a highly recognizable combination of classic lissencephaly with a posterior more severe than anterior gradient similar to PAFAH1B1(LIS1)-related lissencephaly and severe hypoplasia or absence of the corpus callosum; dysplasia of the basal ganglia, hippocampus, and midbrain; and cerebellar hypodysplasia, similar to the tubulinopathies, a group of monogenic tubulin-associated disorders of cortical dysgenesis. Neural cell rosette lineages derived from affected individuals displayed findings consistent with these phenotypes, including abnormal morphology, decreased cell proliferation, and neuronal differentiation. Camsap1-null mice displayed increased perinatal mortality, and RNAScope studies identified high expression levels in the brain throughout neurogenesis and in facial structures, consistent with the mouse and human neurodevelopmental and craniofacial phenotypes. Together our findings confirm a fundamental role of CAMSAP1 in neuronal migration and brain development and define bi-allelic variants as a cause of a clinically distinct neurodevelopmental disorder in humans and mice.

Adaptive functioning in children with neurofibromatosis type 1: relationship to cognition, behavior, and magnetic resonance imaging.

AIM: To characterize the adaptive behavior profile of children with neurofibromatosis type 1 (NF1) and determine its relationship to neuropsychological functioning and non-neoplastic T2-weighted hyperintense brain lesions on brain magnetic resonance imaging (MRI). METHOD: In this cross-sectional study, we retrospectively reviewed neuropsychological reports from 104 children with NF1 (56 males, 48 females; mean age 10y 4mo; standard deviation [SD] 3y 4mo; range 3y 5mo-17y 6mo), and extracted data from a range of cognitive and behavioral measures, including the Adaptive Behavior Assessment System (ABAS). Brain MRI was retrospectively reviewed in 42 individuals. RESULTS: Adaptive Behavior Assessment System scores were continuously distributed and pathologically shifted by 0.79 to 1.26SD across Conceptual, Social, and Practical domains, and 46.5% of individuals had a composite score in the borderline or impaired range. Impairment in adaptive functioning was correlated with deficits in executive function (r=-9.543, p<0.001), externalizing problems (r=-0.366, p<0.001), and attention (r=-9.467, p=0.001). Cluster analysis revealed three distinct phenotypic subgroups, one of which exhibited normal cognitive ability, but impaired adaptive functioning, with persistent deficits in executive function, behavioral problems, and attention-deficit/hyperactivity disorder symptomatology. There was no relationship between ABAS scores and the number or location of unidentified bright objects. INTERPRETATION: Adaptive functioning deficits are common among children with NF1 and are associated with impairment in other cognitive/behavioral domains, independent of general cognitive ability. WHAT THIS PAPER ADDS: Deficits in adaptive behavior are common in children with neurofibromatosis type 1 (NF1). Poor adaptive functioning is associated with impairments in executive function, externalizing behaviors, and attention, regardless of cognitive ability. The presence or location of unidentified bright objects do not predict adaptive behavior skills in children with NF1.

FUNCIONAMIENTO ADAPTATIVO EN NIÑOS CON NEUROFIBROMATOSIS TIPO 1: RELACIÓN ENTRE COGNICIÓN, COMPORTAMIENTO E IMÁGENES DE RESONANCIA MAGNÉTICA: OBJETIVO: Caracterizar el perfil del comportamiento adaptativo de niños con neurofibromatosis tipo 1 (NF1) y determinar la relación entre el funcionamiento neuropsicológico y las lesiones hiperintensas cerebrales no neoplásicas en T2-pesado de la resonancia magnética cerebral (RM). MÉTODO: En este estudio transversal, revisamos de forma retrospectiva reportes neuropsicológicos de 104 niños con NF1 (56 varones, 48 mujeres, media de edad 10 años 4 meses; desviación estándar (DE) 3 años 4 meses; rango 3 años 5 meses a 17 años 6 meses), y se extrajeron datos de una serie de mediciones cognitivas y conductuales, incluyendo el test sistema de evaluación de la conducta adaptativa (Adaptative Behaivor Assesment System ABAS). Se revisaron 42 RM cerebrales de forma retrospectiva. RESULTADOS: Los resultados ABAS fueron continuamente distribuidos y se cambiaron patológicamente entre 0,79 a 1,26 DE en los dominios de lo conceptual, social y práctico, y 46,5 por ciento de los individuos tuvieron un puntaje limítrofe o sin afectación. La afectación en las funciones adaptativas fue correlacionada con los déficits en funciones ejecutivas (r = -9,543, p < 0,001), externalizar problemas (r = -0,366, p < 0,001), y atención (r = -9,467, p = 0,001). El análisis de grupo revelo tres subgrupos fenotípicos distintos, uno de ellos exhibía una habilidad cognitiva tipica, pero afectación en el funcionamiento adaptativo, con déficits persistentes en función ejecutiva, problemas conductuales, y sintomatología de déficit de atención/hiperactividad. No hubo relación entre el puntaje ABAS y el número o localización de imágenes brillantes no identificadas en la RM cerebral. INTERPRETACIÓN: Los déficits de funcionamiento adaptativo son comunes entre niños con NF1 y son asociados con afectación de otros dominios cognitivo/conductual, independiente de la habilidad cognitiva en general.

FUNCIONAMENTO ADAPTATIVO EM CRIANÇAS COM NEUROFIBROMATOSE TIPO 1: RELAÇÃO COM COGNIÇÃO, COMPORTAMENTO, E IMAGEM DE RESSONÂNCIA MAGNÉTICA: OBJETIVO: Caracterizar o comportamento adaptativo de crianças com neurofibromatose tipo 1 (NF1) e determinar sua relação com funcionamento neuropsicológico e lesões em T2 hiperintensas não neoplásticas ao exame de ressonância magnética (RM). MÉTODO: Neste estudo transversal, revisamos retrospectivamente os relatórios neuropsicológicos de 104 crianças com NF1 (56 do sexo masculino, 48 do sexo feminino; média de idade 10a 4m; desvio padrão [DP] 3a 4m; variação 3a 5m-17a6m), e extraímos dados de uma variedade de medidas cognitivas e comportamentais, incluindo o Sistema de Avaliação do Comportamento Adaptativo (SACA). Imagens de RM cerebral foram retrospectivamente revisadas em 42 indivíduos. RESULTADOS: Os escores SACA foram distribuídos continuamente, e patologicamente deslocados em 0,79 a 1,26 DP nos domínios Conceitual, Social e Prático, e 46,5 por cento dos indivíduos tiveram escore composto na faixa limítrofe ou deficiente. Deficiências no comportamento adaptativo se correlacionaram com déficits na função executiva (r = −9,543, p < 0,001), problemas externalizantes (r = −0,366, p < 0,001), e atenção (r = −9,467, p = 0,001). Análise agrupada revelou três subgrupos genotípicos distintos, um dos quais exibiu capacidade cognitiva normal, mas funcionamento adaptativo deficiente, e sintomatologia de transtorno de deficit de atenção e hiperatividade. Não houve relação entre escores SACA e o número ou localização de objetos luminosos não identificados. INTERPRETAÇÃO: Déficits no funcionamento adaptativo são comuns entre crianças com NF1 e são associados com deficiência em outros domínios cognitivos/comportamentais, independente da capacidade cognitiva geral.

Increased prevalence of brain tumors classified as T2 hyperintensities in neurofibromatosis 1.

BACKGROUND: We sought to define the radiologic features that differentiate neoplastic from non-neoplastic T2 hyperintensities (T2Hs) in neurofibromatosis type 1 (NF1) and identify those lesions most likely to require oncologic surveillance. METHODS: We conducted a single-center retrospective review of all available brain MRIs from 68 children with NF1 (n = 190) and 46 healthy pediatric controls (n = 104). All T2Hs identified on MRI were characterized based on location, border, shape, degree of T1 hypointensity, and presence of mass effect or contrast enhancement, and subsequently classified using newly established radiologic criteria as either unidentified bright objects (UBOs) or probable tumors. Lesion classification was pathologically confirmed in 10 NF1 cases. RESULTS: T2Hs were a highly sensitive (94.4%; 95% confidence interval [CI] 86.4%-98.5%) and specific (100.0%; 95% CI 92.3%-100.0%) marker for the diagnosis of NF1. UBOs constituted the majority of T2Hs (82%) and were most frequently located in cerebellar white matter, medial temporal lobe, and thalamus, where they were more likely than probable tumors to be bilateral (p < 0.001) and have nondiscrete borders (p < 0.001). Surprisingly, 57% of children with T2Hs harbored lesions classified as probable tumors, and 28% of children with probable tumors received treatment. In contrast to UBOs, probable tumors were most frequently located within the globus pallidus and medulla, and rarely occurred prior to 3 years of age. CONCLUSIONS: With the implementation of standardized radiologic criteria, a high prevalence of brain tumors was identified in this at-risk population of children, of which nearly one-third required treatment, emphasizing the need for appropriate oncologic surveillance for patients with NF1 harboring nonoptic pathway brain tumors.