RESUMEN
Copy number variants (CNVs) of a 600 kb region on 16p11.2 are associated with neurodevelopmental disorders and changes in brain volume. The authors hypothesize that abnormal brain development associated with this CNV can be attributed to changes in transcriptional regulation. The authors determined the effects of 16p11.2 dosage on gene expression by transcription profiling of lymphoblast cell lines derived from 6 microdeletion carriers, 15 microduplication carriers and 15 controls. Gene dosage had a significant influence on the transcript abundance of a majority (20/34) of genes within the CNV region. In addition, a limited number of genes were dysregulated in trans. Genes most strongly correlated with patient head circumference included SULT1A, KCTD13, and TMEM242. Given the modest effect of 16p11.2 copy number on global transcriptional regulation in lymphocytes, larger studies utilizing neuronal cell types may be needed in order to elucidate the signaling pathways that influence brain development in this genetic disorder.
Asunto(s)
Cromosomas Humanos Par 16 , Variaciones en el Número de Copia de ADN , Duplicación de Gen , Eliminación de Secuencia , Transcriptoma/genética , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/patología , Línea Celular , Expresión Génica/genética , Cabeza/patología , Herpesvirus Humano 4 , Humanos , Ganglios Linfáticos/citología , Ganglios Linfáticos/metabolismo , Análisis por Micromatrices , Tamaño de los Órganos , Reacción en Cadena en Tiempo Real de la Polimerasa , Esquizofrenia/genética , Esquizofrenia/metabolismo , Esquizofrenia/patologíaRESUMEN
Individuals with autism are more likely to carry rare inherited and de novo copy number variants (CNVs). However, further research is needed to establish which CNVs are causal and the mechanisms by which these CNVs influence autism. We examined genomic DNA of children with autism (N = 41) and healthy controls (N = 367) for rare CNVs using a high-resolution array comparative genomic hybridization platform. We show that individuals with autism are more likely to harbor rare CNVs as small as â¼ 10 kb, a threshold not previously detectable, and that CNVs in cases disproportionately affect genes involved in transcription, nervous system development, and receptor activity. We also show that a subset of genes that have known or suspected allele-specific or imprinting effects and are within rare-case CNVs may undergo loss of transcript expression. In particular, expression of CNTNAP2 and ZNF214 are decreased in probands compared with their unaffected transmitting parents. Furthermore, expression of PRODH and ARID1B, two genes affected by de novo CNVs, are decreased in probands compared with controls. These results suggest that for some genes affected by CNVs in autism, reduced transcript expression may be a mechanism of pathogenesis during neurodevelopment.
Asunto(s)
Trastorno Autístico/genética , Dosificación de Gen , Regulación del Desarrollo de la Expresión Génica , ARN Mensajero/análisis , Estudios de Casos y Controles , Niño , Hibridación Genómica Comparativa , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Genoma Humano , Humanos , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Prolina Oxidasa/genética , Prolina Oxidasa/metabolismo , ARN Mensajero/biosíntesis , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Transcripción GenéticaRESUMEN
Recurrent microdeletions and microduplications of a 600-kb genomic region of chromosome 16p11.2 have been implicated in childhood-onset developmental disorders. We report the association of 16p11.2 microduplications with schizophrenia in two large cohorts. The microduplication was detected in 12/1,906 (0.63%) cases and 1/3,971 (0.03%) controls (P = 1.2 x 10(-5), OR = 25.8) from the initial cohort, and in 9/2,645 (0.34%) cases and 1/2,420 (0.04%) controls (P = 0.022, OR = 8.3) of the replication cohort. The 16p11.2 microduplication was associated with a 14.5-fold increased risk of schizophrenia (95% CI (3.3, 62)) in the combined sample. A meta-analysis of datasets for multiple psychiatric disorders showed a significant association of the microduplication with schizophrenia (P = 4.8 x 10(-7)), bipolar disorder (P = 0.017) and autism (P = 1.9 x 10(-7)). In contrast, the reciprocal microdeletion was associated only with autism and developmental disorders (P = 2.3 x 10(-13)). Head circumference was larger in patients with the microdeletion than in patients with the microduplication (P = 0.0007).
Asunto(s)
Cromosomas Humanos Par 16 , Duplicación de Gen , Predisposición Genética a la Enfermedad , Esquizofrenia/genética , Humanos , Factores de RiesgoRESUMEN
Schizophrenia is a devastating neurodevelopmental disorder whose genetic influences remain elusive. We hypothesize that individually rare structural variants contribute to the illness. Microdeletions and microduplications >100 kilobases were identified by microarray comparative genomic hybridization of genomic DNA from 150 individuals with schizophrenia and 268 ancestry-matched controls. All variants were validated by high-resolution platforms. Novel deletions and duplications of genes were present in 5% of controls versus 15% of cases and 20% of young-onset cases, both highly significant differences. The association was independently replicated in patients with childhood-onset schizophrenia as compared with their parents. Mutations in cases disrupted genes disproportionately from signaling networks controlling neurodevelopment, including neuregulin and glutamate pathways. These results suggest that multiple, individually rare mutations altering genes in neurodevelopmental pathways contribute to schizophrenia.