RESUMO
The association of genetic variation with disease and drug response, and improvements in nucleic acid technologies, have given great optimism for the impact of 'genomic medicine'. However, the formidable size of the diploid human genome, approximately 6 gigabases, has prevented the routine application of sequencing methods to deciphering complete individual human genomes. To realize the full potential of genomics for human health, this limitation must be overcome. Here we report the DNA sequence of a diploid genome of a single individual, James D. Watson, sequenced to 7.4-fold redundancy in two months using massively parallel sequencing in picolitre-size reaction vessels. This sequence was completed in two months at approximately one-hundredth of the cost of traditional capillary electrophoresis methods. Comparison of the sequence to the reference genome led to the identification of 3.3 million single nucleotide polymorphisms, of which 10,654 cause amino-acid substitution within the coding sequence. In addition, we accurately identified small-scale (2-40,000 base pair (bp)) insertion and deletion polymorphism as well as copy number variation resulting in the large-scale gain and loss of chromosomal segments ranging from 26,000 to 1.5 million base pairs. Overall, these results agree well with recent results of sequencing of a single individual by traditional methods. However, in addition to being faster and significantly less expensive, this sequencing technology avoids the arbitrary loss of genomic sequences inherent in random shotgun sequencing by bacterial cloning because it amplifies DNA in a cell-free system. As a result, we further demonstrate the acquisition of novel human sequence, including novel genes not previously identified by traditional genomic sequencing. This is the first genome sequenced by next-generation technologies. Therefore it is a pilot for the future challenges of 'personalized genome sequencing'.
Assuntos
Variação Genética/genética , Genoma Humano/genética , Genômica/métodos , Análise de Sequência de DNA/métodos , Alelos , Biologia Computacional , Predisposição Genética para Doença/genética , Genômica/economia , Genômica/tendências , Genótipo , Humanos , Individualidade , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único/genética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Alinhamento de Sequência , Análise de Sequência de DNA/economia , SoftwareRESUMO
Genomic copy number imbalances are being increasingly identified as an important cause of intellectual disability and behavioral abnormalities. The typical deletion in WAGR syndrome encompasses the PAX6 and WT1 genes, but larger deletions have been associated with neurobehavioral abnormalities and obesity. We identified four patients with overlapping interstitial deletions on 11p14.1 and extending telomeric to the WAGR critical domain. The minimal overlapping critical chromosomal region was 2.3 Mb at 11p14.1. The deletions encompass the BDNF and LIN7C genes that are implicated in the regulation of development and differentiation of neurons and synaptic transmission. All patients with this deletion exhibit variable degrees of developmental delay, behavioral problems, and obesity. Our data show that ADHD, autism, developmental delay, and obesity are highly associated with deletion involving 11p14.1 and provide additional support for a significant role of BDNF in obesity and neurobehavioral problems.
Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/genética , Transtorno Autístico/genética , Deleção Cromossômica , Transtornos Cromossômicos/genética , Cromossomos Humanos Par 11/genética , Deficiências do Desenvolvimento/genética , Obesidade/genética , Fenótipo , Transtorno do Deficit de Atenção com Hiperatividade/patologia , Transtorno Autístico/patologia , Criança , Transtornos Cromossômicos/patologia , Deficiências do Desenvolvimento/patologia , Humanos , Hibridização in Situ Fluorescente , Lactente , Masculino , Análise em Microsséries , Obesidade/patologia , Análise de Sequência com Séries de OligonucleotídeosRESUMO
We report on a detailed phenotypic characterization of two patients with novel de novo deletions involving 15q13q14, a chromosomal region immediately distal to the Prader-Willi/Angelman syndrome critical interval. Both cases were detected by the clinical array-based comparative genomic hybridization (array-CGH) and were precisely delineated through the high-density Agilent 244 K oligonucleotide array. The comparison of our patients with previously reported deletion cases involving the 15q13q14 region demonstrated a recurrent pattern of developmental anomalies including mild dysmorphic features, cleft palate/bifid uvula, congenital heart defects (PFO or ASD), developmental delay, and learning disabilities. The potential role of the genes within the deleted region in the pathogenesis of these various phenotypic abnormalities is discussed.
Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 15 , Deficiências do Desenvolvimento/genética , Genoma Humano , Análise de Sequência com Séries de Oligonucleotídeos , Criança , Feminino , Humanos , Hibridização in Situ Fluorescente , Lactente , Masculino , Fenótipo , Testes PsicológicosRESUMO
Interstitial deletions of 6q are rare. We report a detailed clinical and molecular characterization of four patients with interstitial deletion involving 6q25. All of our patients presented with microcephaly, developmental delay, dysmorphic features and hearing loss, whereas two of them had agenesis of the corpus callosum. We determined the size, extent and genomic content of the deletions using high-density array-comparative genomic hybridization (a-CGH), and found that a common segment spanning 3.52 Mb within the 6q25.2-q25.3 region was deleted in all four cases. We hypothesize that a subset of genes in the commonly deleted region are dosage sensitive and that haploinsufficieny of these genes impairs normal development of the brain and hearing.