Variation in Gene Expression in Neurofibromatosis Type 1

1型神经纤维瘤病(NF1)是一种常见的(约100,000美国人)遗传性细胞生长失调疾病。受影响的人可能会发展成多种(数十、数百或数千)称为神经纤维瘤的软性肉质肿瘤。患有NF1的人也会患上恶性肿瘤。NF1的治疗方法有限，没有治愈方法。目前，基本上不可能预测这种疾病的严重程度。除了极少数例外，无论是对相关基因(NF1)的突变检测，还是对其他受影响家庭成员的严重程度，都无助于估计疾病的临床进程。在这项研究中，我们研究了NF1患者家庭中严重程度的广泛差异。在我们关于1型神经纤维瘤病基因表达变化方案的翻译方法中，我们使用各种方法(体检、磁共振成像(MRI)、皮肤和眼睛摄影、超声心动图、牙科评估)对NF1家族进行定量评估。我们计划将这些测量的差异与基因表达的差异相关联，这是由微阵列确定的。最终目标是确定与严重程度相关的基因。这些基因的差异(如单核苷酸多态(SNPs))可能有助于预测疾病的严重性。与严重程度相关的基因产品也可能是有用的治疗靶点。 斯图尔特博士于2004年11月底加入NHGRI。IRB于2005年4月批准了我们的项目，随后不久就开始了招聘工作。到2008财年末，我们已经对大约100名NF1患者进行了表型鉴定，并收集了几乎所有父母的DNA。作为一个试点项目，我们从这组受NF1影响的表型个体中培养了25个淋巴母细胞系(LCL)，收集RNA并将其杂交到微阵列(表达谱分析)。然后，我们研究了各种表型(身高、咖啡斑数量、肿瘤负担等)与阵列上表达的大约24,000个基因中的每一个之间的相关性。我们发现了一种基因，该基因的水平似乎会影响NF1患者的身高。然后，我们扩大了研究范围，培养了大约75名NF1患者和大约25名对照组的LCL。我们目前正在研究这100名受试者的表达谱与表型数据的相关性。我们的目标是1)验证在初步研究中被确定为修饰基因的基因(NF1中的身高)，以及2)识别其他假定的修饰基因。 我们还与国家癌症研究所的Brigitte Widemann博士和Thomas Hornyak博士开发了一个合作项目(使用从长凳到床边项目的资金)，以调查神经纤维瘤的生长和生物学。该项目题为1型神经纤维瘤病皮肤神经纤维瘤的自然历史和生物学，于2006年5月由NHGRI IRB批准。它是用几种成像方式来研究皮肤神经纤维瘤的生长速度和出现率。我们还将活检真皮神经纤维瘤和正常皮肤。为了简化招募，资格标准与我们的主要项目-1型神经纤维瘤病的基因表达变异-重叠。到2008财年末，我们纵向评估了12名NF1患者的皮肤神经纤维瘤。 由于斯图尔特博士接受的是内科医生的培训，他对影响成年人的NF1表现特别感兴趣。为此，我们一直在评估患有NF1的成人中具有独特和未被认识到的疾病特征的个体。到2008财年末，我们已经切除了4例NF1患者的血管球瘤，这是一种不常见但令人痛苦的指尖良性肿瘤。我们在了解肿瘤发展的分子机制方面取得了重大进展，并正在准备一份手稿，详细说明我们的发现。另一份研究成人NF1患者的利希结节的手稿也在准备中。 2008财年，我们在《美国医学遗传学杂志》(American Journal Of Medical Genetics)上发表了一篇关于9q亚端粒缺失综合征的特邀综述。斯图尔特博士称，这是一种罕见的染色体疾病，是另一家机构的遗传学研究员。我们在美国人类遗传学学会2007年年会、美国医学遗传学学会2008年年会和儿童肿瘤基金会2008年年会上公布了我们的发现。

Neurofibromatosis type 1 (NF1) is a common (approximately 100,000 Americans) genetic disorder of dysregulated cell growth. Affected people can develop multiple (tens, hundreds, or thousands) of soft fleshy tumors called neurofibromas. People with NF1 also develop malignant cancers. There are limited therapies and no cures for NF1. At this time it is essentially impossible to predict the severity of the disorder. With few exceptions, neither mutation testing of the involved gene (NF1) nor the severity of other affected family members help in estimating the clinical course of the condition. In this study we study the wide variability in severity seen in families with NF1. In our translational approach in the protocol Variation in Gene Expression in Neurofibromatosis Type 1 we quantitatively evaluate families with NF1 using a variety of methods (physical exam, magnetic resonance imaging (MRI), skin and eye photography, echocardiography, dental evaluation). We plan to correlate differences in these measurements with differences in the expression of genes, as determined by a microarray. The ultimate goal is to identify genes associated with severity. Differences in these genes (such as single nucleotide polymorphisms (SNPs)) may be useful in predicting the severity of the disorder. Gene products associated with severity may also be useful therapeutic targets. Dr. Stewart joined NHGRI at the end of November 2004. The IRB approved our project in April 2005 and recruitment started shortly thereafter. By the end of fiscal 2008, we had phenotyped approximately 100 individuals affected with NF1 and collected DNA from nearly all their parents. As a pilot project, we cultured 25 lymphoblastoid cell lines (LCLs) from this phenotyped group of individuals affected with NF1, harvested RNA and hybridized it to microarrays (expression profiling). We then examined the correlation between a variety of phenotypes (height, number of caf-au-lait spots, tumor burden, etc) and each of the approximately 24,000 genes expressed on the array. We identified a gene whose level appears to influence height in individuals with NF1. We then expanded the investigation and cultured LCLs from approximately 75 individuals with NF1 and approximately 25 controls. We are currently investigating the correlation of expression profiles of these 100 subjects with phenotype data. Our goal is to 1) validate the gene identified in the pilot study as a modifier gene (for height in NF1) and 2) identify other putative modifier genes. We have also developed a collaborative project (using funds from the Bench-to-Bedside program) with Dr. Brigitte Widemann and Dr. Thomas Hornyak of the National Cancer Institute to investigate the growth and biology of neurofibromas. The project, titled Natural history and biology of dermal neurofibromas in neurofibromatosis type 1 was approved by the NHGRI IRB in May 2006. It is designed to investigate the growth rate and rate of appearance of dermal neurofibromas using several imaging modalities. We will also biopsy a dermal neurofibroma and normal skin. To streamline recruiting, the eligibility criteria overlap with that of our primary project, Variation in Gene Expression in Neurofibromatosis Type 1. By the end of fiscal 2008, we were evaluating, longitudinally, the dermal neurofibromas from 12 individuals affected with NF1. Since Dr. Stewart is trained as an internist, he has a special interest in manifestations of NF1 affecting adults. To this end, we have been evaluating individuals with NF1 with unique and under-recognized disease features in the adult. By the end of fiscal 2008 we had resected glomus tumors from four individuals with NF1, which are uncommon but painful benign tumors in the fingertips. We have made significant progress in understanding the molecular mechanism of the development of the tumors and are preparing a manuscript detailing our findings. Another manuscript investigating Lisch nodules in adults with NF1 is also in preparation. In fiscal 2008, we published in the American Journal of Medical Genetics an invited review on the 9q subtelomere deletion syndrome, an uncommon chromosomal disorder Dr. Stewart described as a genetics fellow at another institution. We presented our findings at the 2007 annual meeting of the American Society of Human Genetics, 2008 annual meeting of the American College of Medical Genetics and the 2008 annual meeting of the Childrens Tumor Foundation.