甲状腺激素受体β基因V458A点突变所致甲状腺激素抵抗综合征

目的研究1例甲状腺激素抵抗综合征患者的甲状腺激素受体β(THRB)的基因型。方法收集1例甲状腺激素抵抗综合征患者及其父母外周血标本,提取基因组DNA后,应用PCR技术和直接测序法了解患者及其父母THRB基因有无突变。结果患者THRB基因外显子1～9无突变,第10号外显子在第458个密码子处有点突变(V458A),且为杂合子错义突变。患者父母THRB基因无突变。结论经基因诊断证实患者THRB基因存在V458A突变,突变位于THRB配体结合区。     

TRβ基因突变致甲状腺激素抵抗综合征

目的 研究一甲状腺激素抵抗综合征家系的甲状腺激素受体β( thyroid hormone reecptorβ)的基因突变情况.方法 提取患者及其家系5名成员的外周血基因组DNA,PGR分段扩增TRβ基因1-10号外显子,产物直接进行DNA测序检测突变位点.结果 测序结果显示,该家系中有2名成员TRβ基因第10外显子1642位核苷酸发生C转换为A的错义突变,使该位点所编码的氨基酸由脯氨酸变为苏氨酸(P453T),此种突变为杂合子突变.结论 经基因测序检测诊断证实患者TRβ基因第10外显子存在P453T突变,该突变可能导致了甲状腺激素抵抗综合征发生.     

Brugada综合征SCN5A基因的三个新突变

目的 研究Brugada综合征相关基因SCN5A突变情况。方法 以4例Brugada综合征患者和9例临床可疑Brugada综合征患者为研究对象,采用聚合酶链反应和双脱氧末端终止测序法对所有患者进行SCNSA基因扫描。对阳性结果者进行家系中其他成员的筛查。结果 在1个Brugada综合征家系发现两个杂合突变,即SCN5A基因第3外显子上发现一错义突变（G283A）,导致代表缬氨酸残基的第95位密码子突变为异亮氨酸残基（V95I）,第28外显子上也发现一错义突变（CA946T）,导致代表丙氨酸的第1649位密码子突变为缬氨酸（A1649V）。在1个临床可疑Brugada综合征家系发现一杂合突变,即SCN5A基因第28外显子缺失3个碱基（TCT）,导致代表苯丙氨酸残基的第1617位密码子缺失（delF1617）。结论 在Brugada综合征患者发现了3个SCN5A基因新突变（V95I、A1649V、delF1617）。     

一家族性高胆固醇血症家系低密度脂蛋白受体基因突变分析

为分析一家族性高胆固醇血症家系低密度脂蛋白受体的基因突变，提取患儿及其父母外周血基因组DNA，用聚合酶链反应扩增低密度脂蛋白受体基因的18个外显子。用单链构象多态性分析检测聚合酶链反应产物，对单链构象多态性分析电泳结果异常者进行DNA序列分析。结果发现，单链构象多态性分析发现患者及其母亲第10外显子存在一异常条带。DNA测序结果证实患者第10外显子的471位密码子由AGA同义突变为AGG，483住密码子由TGG突变为TAG，导致在483住提前出现终止密码子。本研究利用聚合酶链反应一单链构象多态性分析方法报道了一个新的低密度脂蛋白受体突变位点。     

家族性高胆固醇血症低密度脂蛋白受体基因突变分析

目的:检测1例家族性高胆固醇血症(FH)先证者及其4代家系成员低密度脂蛋白受体(LDL-R)基因突变,探讨该家族FH可能发病分子机制.方法:收集先证者及其家系成员临床资料和基因组DNA,以基因组DNA为模板,用PCR方法扩增LDL-R基因的启动子和全部18个外显子,PCR产物进行限制性内切酶技术结合DNA测序,核苷酸序列分析结果与Gen Bank比对寻找突变;采用PCR-DNA测序技术检测apoB100基因R3500Q、R3531C和R3500W位点以及枯草溶菌素转化酶9(PCSK9)基因,以排除家族性apoB100缺陷症和PCSK9基因突变.结果:先证者及其部分家系成员第6号外显子发生Cys276X杂合无义突变,为半胱氨酸改变为提前终止密码子,使终止密码子在第276位提前出现,为致病性突变,国内尚无报道;另外,第15号外显子发生Arg744Arg同义突变.其母未发现上述突变,未检测出患者及其家系apoB100基因R3500Q、R3531C和R3500W突变以及枯草溶菌素转化酶9基因突变.结论:此患者及家系LDL-R基因存在Cys276X无义突变,可能是FH的致病突变,该突变是我国FH患者LDLR基因的一种新突变类型.     

中国人A型胰岛素抵抗家系与胰岛素受体基因突变研究

目的探讨胰岛素受体基因突变在严重胰岛素抵抗综合征中的发病机制。方法采用PCR对一临床拟诊A型胰岛素抵抗综合征患者胰岛素受体的22个外显子进行扩增并直接测序,测得突变所在外显子后,将其一级亲属的相应外显子进行扩增并直接测序。结果先证者及其父亲均为胰岛素受体第20号外显子R1174W杂合错义突变,另发现先证者胰岛素受体3处外显子纯合同义突变及6处内含子变异。胰岛素受体第20号外显子R1174W杂合子突变引起胰岛素受体β亚基酪氨酸激酶活性下降和自身磷酸化缺陷。结论胰岛素受体第20号外显子R1174W杂合子突变是导致该家系先证者及其父亲严重胰岛素抵抗的主要原因,不排除环境因素及其它基因突变的合并存在造成临床表型差异的可能。     

Liddle综合征的基因诊断(附4例同胞兄弟上皮钠通道基因突变分析)

目的 Liddle综合征家系成员的基因突变分析。方法 一家系三代4例同胞兄弟均患高血压,其中2例经临床检验诊断为Liddle综合征。抽取三代所有成员的基因组DNA,用PCR法扩增上皮钠通道β及γ亚单位（βENaC,γENaC）第13外显子,直接DNA测序法进行基因突变检测。结果 βENaC基因第13外显子的DNA测序结果显示,4例患病同胞兄弟在该外显子的616号密码子均存在CCC→CTC错义突变,家系中其他成员均未发现基因突变。γENaC基因测序未发现突变。结论 同一个家系中的4例高血压同胞检出βENaC基因突变,在基因水平上确诊为Liddle综合征。     

hMLH1和hMSH2基因在胃癌易感人群中的突变

目的:分析中国北方地区胃癌家系人群及胃癌散发患者hMLH1和hMSH2基因的突变.方法:收集胃癌家族史的胃癌患者16例及5个家系健康人114例,无胃癌家族史的胃癌患者56例,正常人群对照100例.采取外周血,用小样本血液DNA提取试剂盒提取DNA.分别扩增hMLH1的外显子3、8、12、13和外显子16以及hMSH2的外显子5和外显子7,热变性后,用毛细管电泳进行单链构象多态性的分析,对可疑样本进行测序.结果:突变出现在hMLH1基因第8、第12和第16外显子,而外显子3和外显子13没有检测到突变,hMSH2基因的外显子5和外显子7也没有检测到突变.在有家族史的胃癌患者的16例外周血标本中,有6例出现突变,突变率37%;无胃癌家族史的56例患者,总计6例出现突变,突变率11%;胃癌家系健康人群的114例样本中,31例出现突变,突变率27%;在100例对照样本中,5例出现突变,突变率5%.第8外显子的突变点位于219位密码子的第一个碱基(ATC→GTC):第12外显子的突变点位于第384位密码子的第二个碱基(GTT→GAT);第16外显子的突变点位于第553位密码子的第二个碱基(AGT→AGG),这三个突变都是碱基置换.但有家族史的胃癌患者和胃癌家系健康成员的突变率明显高于对照组(P=0.001,0.000),无家族史的胃癌患者突变率虽然略高于对照组,但差异不显著(P=0.204).第16外显子的突变是目前尚未见报道的新的突变.结论:胃癌家系人群体细胞存在与遗传性非息肉性结肠癌(hereditary nonpolyposis colorectal cancer,HNPCC)相似的基因突变.     

CYP17A1基因TAC329AA纯合突变致17α-羟化酶缺陷症一例家系研究

目的　通过对一个 17α 羟化酶缺陷症家系的临床和分子生物学研究 ,探讨其分子机制。方法　针对在本中心就诊的一个 17α 羟化酶缺陷症家系 ,全面收集患者及其家庭成员的临床和实验室资料 ,同时采用PCR和亚克隆测序方法检测 17羟化酶基因 (CYP17A1)序列。结果　患者临床及内分泌功能检查完全符合 17α 羟化酶缺陷症。CYP17A1基因序列分析发现 ,第 6号外显子 3 2 9位密码子发生了TAC3 2 9AA突变 ,引起Tyr3 2 9Lys错义突变和以后的移码突变。患者为纯合突变 ,患者的父母均为携带该突变基因的杂合子。结论　本研究的这个家系 ,CYP17A1基因突变是 17α 羟化酶缺陷症的致病基因。CYP17A1第 6号外显子 3 2 9位密码子TAC被AA替代为一新的纯合突变类型。     

中国人Brugada综合征分子遗传学研究发现一个新的SCN5A基因突变

目的 研究探索中国人Brugada综合征是否存在基因突变及突变类型。并分析突变可能的致病机制。方法 以SCN5A作为候选基因。应用PCR-SSCP技术对4例患及其家系成员进行突变检测，并用DNA直接测序验证。结果 SSCP分析在一个家系内发现SCN5A基因第8外显子PCR产物出现异常带型，而在200例正常对照中均未发现此改变，DNA直接测序显示SCN5A编码区第317位密码子的第三位碱基G→C的错义突变，并导致位于DⅠS5与DⅠS6节段之间与钠通道蛋白“孔”区相关的第一个P-Loop结构上一个赖氨酸（K）被天冬酰胺（N）取代（K317N）。一个家系调查表明，21例家系成员中共有10例携带，其中有症状（4例）均为携带，2例无症状携带有心电图改变，隐性携带占40%，结论 在中国人中发现了Brugada综合征一个新的SCN5A基因突变。     

A clinical syndrome of mild androgen insensitivity

We studied four patients from three kindreds who had normal male body habitus and external genitalia except for short penile length and gynecomastia. Prostate size was small in all patients and spermatogenesis was decreased markedly in one and absent in three. Testicular biopsies in two patients revealed normal histology but evidence of spermatogenic arrest at the spermatocyte stage. Circulating levels of testosterone and LH were increased and the testosterone-dihydrotestosterone ratios were normal. Plasma estradiol was elevated in three of the four patients. Serum FSH levels were significantly elevated in only one patient. The response of LH and FSH to LHRH stimulation was normal in the two patients who were tested. Despite the normal male phenotype, the laboratory studies suggested the diagnosis of androgen insensitivity. This was confirmed in two patients by finding decreased dihydrotestosterone-binding capacity in genital skin fibroblasts. Two of the patients had normal levels of androgen receptor binding, suggesting that their defect represented a mild form of androgen insensitivity with normal receptor activity. These results demonstrated that mild forms of androgen insensitivity exist in which the only obvious clinical manifestations may be the presence of reduced penile length, gynecomastia, and/or infertility. The incidence of androgen insensitivity among men with these subtle phenotypic abnormalities, including infertility, remains to be determined.     

雄激素和雄激素受体对肝癌细胞株PEG10表达的作用

目的 探讨雄激素和雄激素受体(AR)对肝癌细胞株PEG10表达的调控作用.方法 设计合成针对人ARsiRNA,并转染HepG2和7404肝癌细胞株.用双氢睾丸酮(DHT)干预HepG2细胞.Western Blot检测AR和PEG10表达水平.结果 从3对AR siRNA中筛选到1对siRNA(AR siRNA-3),它在2种肝癌细胞株中均可有效抑制AR的表达,其抑制作用呈剂量依赖关系.2种肝癌细胞株中,浓度为240 nmol/L的AR siRNA-3在转染后24 h,对AR抑制效率可达80%以上,且抑制效果可持续至72 h.AR siRNA-3转染24h后PEG10表达水平降低,转染48 h后,PEG10表达水平降低非常明显,72 h后PEG10表达有所上升.DHT可促进HepG2细胞PEG10的表达,呈剂量依赖关系.DHT对AR表达未见明显作用.结论 雄激素和AR参与了肝癌细胞株PEG10表达的调控.这可能是男性肝细胞癌发病率较高的原因之一.     

Estrogen and androgen production rates in two brothers with Reifenstein syndrome

Defects of the androgen receptor in 46,XY individuals cause aberrant virilization that varies from a female phenotype to men with minor defects. More severely affected individuals also develop gynecomastia associated with enhanced estradiol secretion by the testis. However, the degree of breast development does not correlate with the rate of estrogen production, leading us to propose that feminization is a function of the degree of androgen resistance as well as the rate of estrogen formation. To test this hypothesis we measured estrogen and androgen formation in two brothers with perineoscrotal hypospadias and severe gynecomastia (the Reifenstein phenotype) due to a mutation that impairs androgen receptor function. Rates of estradiol production (60 and 70 micrograms/day) were elevated, but were not as high as in previously studied men with a similar phenotype. We conclude that the variable degree of feminization in this disorder cannot be explained by androgen resistance alone.     

A comprehensive endocrine description of Kennedy's disease revealing androgen insensitivity linked to CAG repeat length

Our study aims to provide a comprehensive view of the endocrine features in Kennedy's disease (KD). Twenty-two men with KD underwent detailed endocrine investigations. Clinical signs of partial androgen resistance were present in more than 80% of the patients, with gynecomastia being the most prominent. Gynecomastia was postpubertal but appeared before muscular weakness in most cases. Thirteen patients had alteration of testicular exocrine function. Hormonal profile of partial androgen resistance was present in 86% of the patients, with an elevated testosterone level in 68%. Androgen insensitivity seems to appear later in life in KD, similar to the development of neurological signs. Although we confirm the previously reported correlation between the CAG repeat length and the early onset of the neurological disease, we describe a significant correlation between repeat length and the age of onset of gynecomastia as well as biological indexes of androgen insensitivity. This is supported by numerous in vitro data correlating variations in the CAG tract with androgen receptor activity; the longer the CAG repeats, the weaker the receptor transactivation. Ours is the first study to show such a clear and prominent pattern of androgen insensitivity in KD. In clinical practice, KD patients are often misdiagnosed as having amyotrophic lateral sclerosis. Careful examination of the endocrine component could avoid such a deleterious misdiagnosis.     

Cardiovascular risks of androgen deprivation therapy

Prostate adenocarcinoma is the most common cancer type in the male sex after skin cancer. Among the several types of treatment for prostate cancer, the androgen deprivation therapy has been highly recommended in patients with metastatic or locally advanced disease, which probably results in increased survival. However, the androgen deprivation is the cause of several adverse effects. Complications such as osteoporosis, sexual dysfunction, gynecomastia, anemia and body composition alterations are well-known effects of the therapy. Recently, a number of metabolic complications have been described, such as increase in the abdominal circumference, insulin resistance, hyperglycemia, diabetes, dyslipidemia and metabolic syndrome, with a consequent increase in the risk of coronary events and cardiovascular mortality in this specific population. This update article presents a literature review carried out at MEDLINE database of all literature published in English from 1966 to June 2009, using the following key words: androgen deprivation therapy, androgen suppression therapy, hormone treatment, prostate cancer, metabolic syndrome and cardiovascular disease, with the objective of analyzing which would be the actual cardiovascular risks of androgen deprivation therapy, also called androgen suppression, in patients with prostate cancer.     

The role of androgens and the androgen receptor in cycling endometrium

Androgens and the androgen receptor (AR) are not only required for male reproductive function, they are also essential for female reproductive physiology. Widely expressed in female reproductive tissues, AR levels fluctuate in a regulated manner in the cycling endometrium. Female androgen production depends on the adrenal glands and expression of key enzymes in the endometrium that facilitate local androgen biosynthesis and conversion. Moreover, levels of circulating androgens, in women of reproductive age, fluctuate in a cycle-dependent manner and a mid-cycle peak is associated with conception. AR and androgen signalling have a decisive role in the differentiation of human endometrial stromal cells into decidual cells. Compelling evidence for androgen signalling in the regulation of endometrial function pertaining to implantation and pregnancy is provided by epidemiological studies demonstrating a strong association between polycystic ovary syndrome, premature ovarian failure or advanced maternal age and adverse pregnancy outcome. Thus, androgen signalling is an essential component of normal endometrial physiology and its perturbation is associated with reproductive failure.     

Improvement of spermatogenesis after treatment with the antiestrogen tamoxifen in a man with the incomplete androgen insensitivity syndrome

A 32-yr-old man with a history of hypospadias, unilateral cryptorchidism, and pubertal gynecomastia (all surgically corrected) presented with complaints of infertility. Examination revealed scant virilization, recurrence of gynecomastia, small but normal sized testes, small prostate, and oligospermia. His plasma LH, testosterone, dihydrotestosterone, and estradiol levels were high, and his plasma FSH was below the reference range of adult men. An assay of pubic skin fibroblast androgen receptors confirmed the diagnosis of a form of incomplete androgen insensitivity syndrome. Administration of the estrogen receptor antagonist tamoxifen (10 mg, twice daily) induced an increase in plasma FSH greater than that which occurred in six men with idiopathic oligospermia. This man's wife conceived three times during a period of 5 yr, each time after he had received tamoxifen for 12-20 weeks and had considerable improvement of sperm parameters. Conversely, upon cessation of tamoxifen therapy, the semen abnormalities returned. These results indicate that estrogen action impaired this man's fertility, and the impairment could be reversed by administration of an estrogen receptor antagonist.     

A mutation of the androgen receptor associated with partial androgen resistance, familial gynecomastia, and fertility

A family is described in which gynecomastia and undervirilization in five men (four of whom have fathered children) were inherited in a manner compatible with an X-linked defect. Three members from whom blood could be obtained had supranormal serum testosterone and normal LH and FSH levels. One man had severe oligospermia with decreased motility, and one had normal sperm density and motility. In fibroblasts cultured from genital skin biopsies from two of the men, the levels of androgen receptor and affinity of binding of receptor to dihydrotestosterone were normal. However, androgen binding in fibroblast monolayers was thermolabile, up-regulation of receptor levels did not occur after prolonged incubation of monolayers with dihydrotestosterone or methyltrienolone, and dissociation rates at 37 C were increased with the synthetic androgen mibolerone. In addition, in cytosol preparations the androgen receptor protein was unstable. This disorder probably represents the most subtle functional abnormality of androgen receptor characterized to date, since it is compatible with normal male phenotypic development and in some affected men with fertility. It follows that infertility is not an invariable feature of androgen resistance as we previously suggested.     

Gynecomastia as a familial incomplete male pseudohermaphroditism type 1: a limited androgen resistance syndrome.

Four postpubertal 46 XY male patients with an inherited form of bilateral gynecomastia were studied to delineate the nature of the disease. Normal serum FSH and moderately elevated serum LH with concomitantly increased circulating levels of testosterone (T) and estradiol (E2) were found persistently in all cases in blood samples drawn at frequent intervals. LRH pituitary stimulation resulted in an exaggerated LH response and a normal FSH response. Chronic administration of T-cyclopentylate failed to decrease serum LH levels. The peripheral conversion rate of androstenedione to estrone was within normal limits. All patients had low ejaculate volumes with relatively normal spermatozoa counts. Testicular biopsies revealed normal Leydig cells and complete spermatogenesis. Urological examination disclosed that the prostate gland was extremely small. The breast tissue demonstrated the presence of tubular structures as well as the specific binding of [3H]T and [3H]dihydrotestosterone (DHT), which was inhibited by nonlabeled T, DHT, E2, and progesterone, but not by cortisol. The pedigree suggested a recessive X-linked inherited trait. A patient with a nonfamilial form of gynecomastia served as a control in all studies. These data were interpreted as demonstrating that this inherited type of gynecomastia represents the mildest expression of the androgen resistance syndromes and, therefore, belongs to the type 1 form of familial incomplete male pseudohermaphroditism.