SRY mutation and tumor formation on the gonads of XP pure gonadal dysgenesis patients.

We report three patients with XY pure gonadal dysgenesis. Two of these patients developed gonadoblastoma and associated dysgerminoma. Molecular analyses were undertaken to investigate the relationship between the formation of these tumors and Y chromosome aberrations. Deletion analyses were performed by polymerase chain reaction (PCR) amplification of Y chromosome-specific DNA sequences (PABY, SRY, DYS250, DYS254, and DYZ1). A cryptic deletion of the short arm of the Y chromosome that included the PABY, SRY, DYS250, and DYS254 loci was observed in one of the patients (22-years-old) with an associated tumor. In the other two patients who did not demonstrate such a deletion, the sequence of the SRY open reading frame was determined by the dideoxynucleotide method. Two nucleotide substitutions followed by a seven nucleotide deletion were observed in the 3' end of HMG (high mobility group)-box in the other patient (15-years-old) with an associated tumor. The patient (22-years-old) without an associated tumor did not have the cryptic deletion or mutation of SRY. A Y chromosome specific sequence (DYZ1) was demonstrated by PCR amplification of microdissected tumor tissues from these two patients. These results suggest that SRY may play a role in the formation of gonadal tumors, especially dysgerminoma.     

A novel frame shift mutation in the HMG box of the SRY gene in a patient with complete 46,XY pure gonadal dysgenesis.

Pure gonadal dysgenesis or Swyer syndrome is a sex-reversal disorder resulting from embryonic testicular regression sequences especially during the first few weeks of fetal life and is induced by mutations in the SRY gene. In the present report, we describe a nonmosaic XY sex-reversed female with pure gonadal dysgenesis. Molecular analysis using sequential PCR to detect Y chromosomal microdeletions showed the presence of SRY, ZFY and AZFa, b and c regions. Automated sequencing of the SRY region revealed a new mutation (deletion of A (adenine) in codon 82 at position +244), leading to a frame shift mutation within the helix I of the HMG-box domain. This mutation generates a truncated protein and is very likely to produce an impairment of SRY DNA binding activity. The present findings further support the functional importance of the putative DNA binding activity of the SRY HMG-box domain.     

Identification of novel SRY mutations and SF1 (NR5A1) changes in patients with pure gonadal dysgenesis and 46,XY karyotype

Primary amenorrhea due to 46,XY disorders of sexual development (DSD) is complex with the involvement of several genes. Karyotyping of such patients is important as they may develop dysgerminoma and molecular analysis is important to identify the underlying mechanism and explore the cascade of events occurring during sexual development. The present study was undertaken for the genetic analysis in seven patients from five families presenting with primary amenorrhea and diagnosed with pure gonadal dysgenesis. Karyotyping was done and the patients were screened for underlying changes in SRY, desert hedgehog (DHH), DAX1 (NR0B1) and SF1 (NR5A1) genes, mutations in which are implicated in DSD. All the patients had 46,XY karyotype and two novel SRY mutations were found. In Family 1 (Patient S1.1) a missense mutation c.294G>A was seen, which results in a stop codon at the corresponding amino acid (Trp98X) and in Family 2 (Patients S2.1, S2.2 and S2.3), a missense mutation c.334G>A (Glu112Leu) was identified in all affected sisters. Both mutations were seen to occur in the conserved high mobility group box of SRY gene. One heterozygous change c.427G>A resulting in Glu143Lys in DHH gene in one patient and two heterozygous changes in the intronic region of SF1 (NR5A1) gene (c.244+80G>A+ c.1068-20C>T) in another patient were noted. One individual did not show changes in any of the genes analyzed. These results reiterate the importance of SRY and others, such as SF1 (NR5A1) and DHH, that are involved in the cascade of events leading to sex determination and also their role in sex reversal.     

6例性别异常患者的SRY基因分析

本文采用ＰＣＲ扩增、琼脂糖凝胶电泳方法，检测了６例性别异常患者的ＳＲＹ基因。结果表明，３例４６，ＸＹ女性患者中，１例ＳＲＹ基因阴性，２例呈阳性；１例如，ＸＸ男性，ＳＲＹ基因呈阳性；另２例两性畸形患者ＳＲＹ基因呈阳性。分析认为，４６，ＸＹ女性性反转，是由于ＳＲＹ基因丢失或突变所致；４６，ＸＸ男性性反转，是由于ＸＰ－ＹＰ易位引起；而两性畸形的发生则与ＳＲＹ以外的其它性别决定基因有关。     

A new de novo mutation (A113T) in HMG box of the SRY gene leads to XY gonadal dysgenesis.

We describe a new point mutation in the SRY gene of a Chinese XY female with gonadal dysgenesis (Swyer syndrome). Using the double stranded DNA cycle sequencing method, a single nucleotide substitution of G-->A was identified at codon 113 of the patient's SRY gene, resulting in a conservative amino acid change from alanine (A) to threonine (T) at a residue that lies within the putative DNA binding motif. With this mutation, one MnlI recognition site is abolished and a new BsmAI site is present in the DNA sequence of the SRY gene; therefore, it is easily detected by analysis of the digestion of the amplified SRY DNA fragment on an electrophoretic agarose gel. In situ hybridisation to the XY female's chromosomes showed that her mutant SRY gene was indeed located on the short arm of her Y chromosome. The SRY mutation in the XY female reported here occurred de novo, as sequence analysis showed that it was not present in her father or other family members.     

Description and functional implications of a novel mutation in the sex-determining gene SRY

The sex-determining gene SRY was screened for molecular alteration in an XY sex-reversed female by single-strand conformation polymorphism (SSCP) technique. An A-to-G transition was detected which leads to an exchange of a tyrosine by a cysteine in the SRY protein. The affected tyrosine residue located at the C terminus of the DNA binding protein is evolutionarily strongly conserved among the members of the HMG box containing proteins. Using gel shift assay and peptide synthesis such a mutation is shown to abolish the SRY protein DNA binding ability. The involvement of this particular amino acid in the binding specificity is also discussed. © 1994 Wiley-Liss, Inc.     

46, XY gonadal dysgenesis: new SRY point mutation in two siblings with paternal germ line mosaicism

Stoppa‐Vaucher S, Ayabe T, Paquette J, Patey N, Francoeur D, Vuissoz J‐M, Deladoëy J, Samuels ME, Ogata T, Deal CL. 46, XY gonadal dysgenesis: new SRY point mutation in two siblings with paternal germ line mosaicism. Familial recurrence risks are poorly understood in cases of de novo mutations. In the event of parental germ line mosaicism, recurrence risks can be higher than generally appreciated, with implications for genetic counseling and clinical practice. In the course of treating a female with pubertal delay and hypergonadotropic hypogonadism, we identified a new missense mutation in the SRY gene, leading to somatic feminization of this karyotypically normal XY individual. We tested a younger sister despite a normal onset of puberty, who also possessed an XY karyotype and the same SRY mutation. Imaging studies in the sister revealed an ovarian tumor, which was removed. DNA from the father's blood possessed the wild type SRY sequence, and paternity testing was consistent with the given family structure. A brother was 46, XY with a wild type SRY sequence strongly suggesting paternal Y‐chromosome germline mosaicism for the mutation. In disorders of sexual development (DSDs), early diagnosis is critical for optimal psychological development of the affected patients. In this case, preventive karyotypic screening allowed early diagnosis of a gonadal tumor in the sibling prior to the age of normal puberty. Our results suggest that cytological or molecular diagnosis should be applied for siblings of an affected DSD individual.     

A heterozygous mutation in the desert hedgehog gene in patients with mixed gonadal dysgenesis

Aetiology of mixed gonadal dysgenesis (MGD) has not been completely elucidated. Molecular analyses have failed to demonstrate the presence of mutations in sex-determining region on Y chromosome (SRY); it has been suggested that these individuals may bear mutations in other genes involved in the testis-determining pathway. Desert hedgehog's (DHH) importance regarding male sex differentiation has been demonstrated in various studies we describe here, for the first time, two cases of MGD in which a monoallelic single base deletion in DHH is associated with the disorder. Genomic DNA was isolated from paraffin-embedded gonad tissue from 10 unrelated patients with MGD and three controls; in addition to, DNA from peripheral blood leukocytes in 100 controls. Coding sequence abnormalities in DHH were assessed by exon-specific PCR, single-stranded conformation polymorphism (SSCP) and direct sequencing. In two patients, a heterozygous 1086delG in exon 3 was found. Comparing previously described mutations in DHH to the one observed in this study, we can affirm that the phenotypic spectrum of patients with gonadal dysgenesis due to mutations in DHH is variable. This study continues to demonstrate the importance that DHH has in mammalian male sexual differentiation, providing extended evidence that DHH constitutes a key gene in gonadal differentiation.     

Novel mutations affecting SRY DNA-binding activity: the HMG box N65H associated with 46,XY pure gonadal dysgenesis and the familial non-HMG box R30I associated with variable phenotypes

The SRY gene (sex-determining region of the Y chromosome) initiates the process of male sex differentiation in mammalians. In humans mutations in the SRY gene have been reported to account for 10-15% of the XY sex reversal cases. We describe here two novel missense mutations in the SRY gene after the screening of 17 patients, including 3 siblings, with 46,XY gonadal dysgenesis and 4 true hermaphrodites. One of the mutations, an A to C transversion within the HMG box, causes the N65H substitution and it was found in a patient presenting 46,XY pure gonadal dysgenesis. The Escherichia coli expressed SRY(N65H) protein did not present DNA-binding activity in vitro. The other mutation, a G to T transversion, causes the R30I substitution. This mutation was found in affected and nonaffected members of a family, including the father, two siblings with partial gonadal dysgenesis, a phenotypic female with pure gonadal dysgenesis, and three nonaffected male siblings. The G to T base change was not found in the SRY sequence of 100 normal males screened by ASO-PCR. The R30I mutation is located upstream to the HMG box, within the (29)RRSSS(33) phosphorylation site. The E. coli expressed SRY(R30I) protein was poorly phosphorylated and consequently showed reduced DNA-binding capacity in vitro.     

家族性高胆固醇血症家系低密度脂蛋白受体基因剪接突变的研究

目的　检测中国汉族家族性高胆固醇血症 (familial hypercholesterolemia,FH)大家系低密度脂蛋白受体 (low density lipoprotein receptor,L DL R)基因突变 ,探讨 FH发病的分子机理。方法　首先采用聚合酶链反应 -限制性片段长度多态性 (polymerase chain reaction- restriction fragment lengthpolymorphism,PCR- RFL P)技术检测载脂蛋白 B1 0 0 (apo B1 0 0 )基因 Q35 0 0 R突变 ,排除家族性 apo B1 0 0 缺陷症 ,再采用 PCR扩增结合核苷酸序列分析检测 1例临床诊断为 FH纯合子患儿及其家系成员 L DL R基因启动子和全部 18个外显子片段 ,结果与 Gen Bank公布的该基因正常序列对比找出突变 ,并在家系其他成员中证实该突变。结果　该患儿 L DL R基因第 3内含子剪接供体处存在 IN 5′GT→AT纯合剪接突变 ,并且在家系中得到证实 ,一级和二级亲属中各发现 2例相同位点和相同形式的杂合子 ,其基因型表现为野生型和突变型杂合现象。同时未检测出患儿及其父母 apo B1 0 0 Q35 0 0 R突变。结论　发现 L DL R基因第 3内含子 G→ A纯合剪接突变 ,可能是该 FH家系发病的分子基础 ;检测该突变对临床干预和遗传指导有参考价值。     

一个肌萎缩侧索硬化家系的SOD1基因突变

肌萎缩侧索硬化 (amyotrophic lateral sclerosis,ALS)是一种以脑和脊髓中大的运动神经元变性为特征的神经系统变性疾病。 5 %～ 10 %的患者有家族性。临床表现为缓慢起病 ,进行性发展 ,逐渐出现四肢肌肉的无力、萎缩 ,伴锥体束征等。临床治疗非常困难。目前已肯定编码铜、锌超氧化物歧化酶 (Cu/ Zn superoxidedismutase,Cu/ Zn- SOD)的 SOD1基因突变可引起部分家族性 ALS的发病[1] 。我们对重庆地区一个具有特殊临床表型的 ALS家系进行了 SOD1基因检测 ,结果发现部分患者第 2和第 5外显子有明显异常。1　对象与方法1.1　对象　受…     

家族性腺瘤性息肉病家系中一种新的APC基因的胚系突变

目的研究1个家族性腺瘤性息肉病家系的腺瘤样息肉病基因（adenomatous polyposis coli，APC）的胚系突变。方法经结肠镜、组织病理学检查和家族史的调查，确定了1例家族性腺瘤性息肉病（familial adenomatous polyposis，FAP）患者。应用多重连接依赖性探针扩增（multiplex ligation-dependent probe amplification，MLPA）、变性高效液相色谱（denaturing high-performance liquid chromatography，DHPLC）测序等技术对这一家系的成员进行系统的APC全基因筛查。结果在此家系中发现一个新的APC基因的胚系突变c。1999 C〉T（Q667X），这一突变造成了APC基因终止密码子的形成，从而形成有功能障碍的截短蛋白。临床上，此突变可引起严重的FAP症状，早发结直肠腺瘤和腺癌。结论Q667X胚系突变是引起该家系临床表型的原因，受累成员可考虑大肠预防性切除手术。     

Clinical expression and SRY gene analysis in XY subjects lacking gonadal tissue

In several syndromes genetic males lack gonadal tissue. A range of phenotypes are seen, which varies from complete female external genitalia to anorchic subjects with sexual infantilism. Differences in phenotypic expression depend on the stage at which testes degenerated during intrauterine development. Although most cases of these syndromes are sporadic, several instances of familial recurrence suggest a genetic origin. To help elucidate the source, we performed molecular analysis of the complete SRY gene open reading frame in two subjects with true agonadism and in two with anorchia. Our results add to previous findings indicating that molecular defects in SRY are not readily identified as a cause of these syndromes.