Terminal Deletion of Chromosome 2q Associated with Graves' Disease : A Case Report and Literature Review

二號染色體長臂尾端的缺失(terminal deletion of 2q)是罕見的染色體異常疾病，而葛瑞夫茲氏病(Graves' disease)是一種自體免疫性的甲狀腺功能亢進，它可以發生在任何一個年齡層但是少見於幼兒，第二號染色體長臂尾端缺失合併葛瑞夫茲氏病則是非常罕見。本文提出一病例報告，一位二十二歲的女性病患，染色體的核型是46, XX, del (2) (2q37.1-qter)，除具典型的輕微外觀異常之外，且合併葛瑞夫茲氏病。病人有輕微的智障、個性開朗、多話、好奇、無防禦心、與部分文獻所報告的自閉行為、缺乏社經能力、重複性的動作及興趣並不同，病人的皮膚狀況非常不好，除皮膚非常鬆軟之外，長年為濕疹、癢皮、毛囊炎及蜂窩性組織炎所苦。關節的鬆軟和兩腳長短不一及容易感染與細胞外基質的病變如存於2q37的COL6A3基因是否有關仍待進一步研究。其肢端的異常包括小手、小腳、長短腳、短指、左腳第一與第二趾間很寬、左腳第二趾的蹠骨很長，與文獻報告嚴重的肢端異常如裂手、裂腳常見的病變位置是在2q24-31雖有不同，根據其他文獻病人的統計推測2q37.1-qter此段缺失的染色體當中應有影響肢體發育的基因存在，只是目前還無法了解其致病的機轉。CTLA4基因位於2q33，目前發現與葛瑞夫茲氏病高度相關，而PDCD1基因位於2q37.3是免疫球膜蛋白，存在T和B細胞膜上，與T和B細胞之間的互相調控有關，病人的一個PDCD1對偶基因的缺失，是否與第二號染色體長臂尾端缺失基因交互作用的相關性仍待進一步研究。二號染色體長臂尾端的缺失所合併的其他異常也將在本文中回顧及討論。

關鍵字

染色體異常；第二號染色體長臂尾端缺失；葛瑞夫茲氏病

並列摘要

Terminal deletion of chromosome 2q is a rare chromosomal disorder. The clinical phenotype is mild but is usually associated with distinct craniofacial phenotype and variable digital anomalies. We describe a 22-year-old obese woman with terminal deletion of 2q. A high-resolution blood chromosome study revealed a 46, XX, del(2)(q37.1) karyotype in a total of 20 cells. She had typical facial dysmorphisms including frontal bossing, long eyelashes, arched eyebrows, mid-facial hypoplasia, and low set, dysplastic ears. She was mildly mentally retarded, talkative, happy, and curious. This cheerful behavior was different from behavior anomaly previously reported in patients with this deletion. Her limb anomalies were milder as compared with the split hands and split foot of patients with deletion of 2q24-31. Excessive sweating and chronic diarrhea were noted since early infancy, and Graves' disease was diagnosed at the age of 4 years. To our knowledge, this is the first report of a terminal deletion of the long arm of chromosome 2 associated with Graves' disease. Since the genetic contribution of autoimmune thyroid disease are found to be associated with human leukocyte antigen (HLA) genes, thyrotropin gene (TSH), cytokine genes, and immune modulators such as cytotoxic T lymphocyte antigen-4 gene (CTLA4). CTLA4 is located on chromosome 2q33 and encodes a T cell surface molecule critical for controlling T-cell tolerance. The association between immune dysregulation and genes in the region of 2q37.1~qter such as the programmed cell death 1 (PTCD1) gene is worth further investigation.

並列關鍵字

chromosome anomaly ； chromosome 2q37.1 deletion ； Graves' disease

國際替代計量

Terminal Deletion of Chromosome 2q Associated with Graves' Disease : A Case Report and Literature Review

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