Analysis of CYP17A1 gene variants in 5 patients with 17-hydroxylase deficiency / 中华医学遗传学杂志

OBJECTIVE@#To identify pathogenic variants in 5 sporadic patients and two Chinese pedigrees affected with 17-hydroxylase deficiency (17-OHD).@*METHODS@#Peripheral blood samples were collected with informed consent. Variants of CYP17A1 gene were screened by PCR and Sanger sequencing. Suspected mutations were validated in other members of the pedigrees.@*RESULTS@#Gene sequencing has identified a homozygous c.985_987delTACinsAA (Y329Kfs) mutation in exon 6 of the CYP17A1 gene in 4 patients and the sister of case 3. Case 1 was found to harbor compound heterozygous mutations c.1459_1467del9 (p.D487_F489del) and c.1244-3C>A. The parents and brother of cases 2 and 5 were heterozygous carriers of a c.985_987delTACinsAA(Y329Kfs) mutation.@*CONCLUSION@#Mutations of the CYP17A1 gene probably underlie the pathogenesis of 17-OHD, for which c.985_987delTACinsAA(Y329Kfs) is the most common. The c.1244-3C>A is a novel mutation. Above results have facilitated genetic counseling for the affected families.

Functional Identification of Compound Heterozygous Mutations in the CYP17A1 Gene Resulting in Combined 17α-Hydroxylase/17,20-Lyase Deficiency

BACKGROUND: We previously reported a patient with congenital adrenal hyperplasia (CAH) with compound heterozygous mutations in the cytochrome P450 17A1 (CYP17A1) gene. One allele had a p.His373Leu and the other a new p.Glu383fsX36 mutation. The aim of this study was to investigate the functional properties of a new allele present in a compound heterozygote of CYP17A1. METHODS: To understand how p.His373Leu and p.Glu383fsX36 affect P450c17 enzymatic activity, wild type and mutant CYP17A1 cDNAs were cloned into flag-tagged pcDNA3 vector and introduced into human embryonic kidney cells 293T (HEK293T) cells. Protein expression levels of CYP17A1 were then analyzed. And the activities of 17α-hydroxylase and 17,20-lyase of CYP17A1 were evaluated by measuring the conversion of progesterone to 17α-hydroxyprogesterone and of 17α-hydroxypregnenolone to dehydroepiandrosterone, respectively. In addition a computer model was used to create the three-dimensional structure of the mutant CYP17A1 enzymes. RESULTS: Production of the p.His373Leu mutant protein was significantly lower than that of the wild type protein, and the p.Glu383fsX36 protein was hardly produced. Similarly the enzymatic activity derived from the p.His373Leu mutant vector was significantly lower than that obtained from the wild type vector, and little activity was obtained from the p.Glu383fsX36 vector. Three-dimensional modeling of the enzyme showed that p.His373 was located in region important for heme-binding and proper folding. Neither the p.His373Leu nor the p.Glu383fsX36 mutant protein formed a heme-binding structure. CONCLUSION: Enzyme activity measured in both mutants disappeared completely in both 17α-hydroxylase and 17,20-lyase. This result accounts for the clinical manifestations of the patient with the compound heterozygous CYP17A1 mutations.

Combined Effect of the PGR + 331C > T, CYP17A1 -34A > G and CYP19A1 1531G > A Polymorphisms on the Risk of Developing Endometriosis / Efeito combinado dos polimorfismos PGR + 331C > T, CYP17A1 -34A > G e CYP19A1 1531G > A no risco de desenvolvimento da endometriose

Abstract Purpose To evaluate the magnitude of the association of the polymorphisms of the genes PGR, CYP17A1 and CYP19A1 in the development of endometriosis. Methods This is a retrospective case-control study involving 161 women with endometriosis (cases) and 179 controls. The polymorphisms were genotyped by real-time polymerase chain reaction using the TaqMan system. The association of the polymorphisms with endometriosis was evaluated using the multivariate logistic regression. Results The endometriosis patients were significantly younger than the controls (36.0±7.3 versus 38.0±8.5 respectively, p = 0.023), and they had a lower body mass index (26.3±4.8 versus 27.9±5.7 respectively, p = 0.006), higher average duration of the menstrual flow (7.4±4.9 versus 6.1±4.4 days respectively, p = 0.03), and lower average time intervals between menstrual periods (25.2±9.6 versus 27.5±11.1 days respectively, p = 0.05). A higher prevalence of symptoms of dysmenorrhea, dyspareunia, chronic pelvic pain, infertility and intestinal or urinary changes was observed in the case group when compared with the control group. The interval between the onset of symptoms and the definitive diagnosis of endometriosis was 5.2±6.9 years. When comparing both groups, significant differences were not observed in the allelic and genotypic frequencies of the polymorphisms PGR + 331C > T, CYP17A1 -34A > G and CYP19A1 1531G > A, even when considering the symptoms, classification and stage of the endometriosis. The combined genotype PGR + 331TT/CYP17A1 -34AA/CYP19A11531AA is positively associated with endometriosis (odds ratio [OR] = 1.72; 95% confidence interval [95%CI] = 1.09-2.72). Conclusions The combined analysis of the polymorphisms PGR-CYP17A1-CYP19A1 suggests a gene-gene interaction in the susceptibility to endometriosis. These results may contribute to the identification of biomarkers for the diagnosis and/or prognosis of the disease and of possible molecular targets for individualized treatments.

Resumo Objetivo Avaliar a magnitude de associação de polimorfismos nos genes PGR, CYP17A1 e CYP19A1 no desenvolvimento da endometriose. Métodos Este é um estudo retrospectivo do tipo caso-controle, envolvendo 161 mulheres com endometriose (casos) e 179 controles. Os polimorfismos foram genotipados pela reação em cadeia da polimerase em tempo real utilizando o sistema TaqMan. A associação dos polimorfismos estudados com a endometriose foi avaliada pela regressão logística multivariada. Resultados As pacientes com endometriose eram significativamente mais jovens do que os controles (36,0±7,3 versus 38,0±8,5, respectivamente, p = 0,023), apresentaram um índice de massa corporal menor (26,3±4,8 versus 27,9±5,7, respectivamente, p = 0,006), maior tempo médio de duração do fluxo menstrual (7,4±4,9 versus 6,1±4,4 dias, respectivamente, p = 0,03) e menor tempo médio do intervalo entre as menstruações (25,2±9,6 versus 27,5±11,1 dias, respectivamente, p = 0,05). Uma maior prevalência dos sintomas de dismenorreia, dispareunia, dor pélvica crônica, infertilidade, alterações intestinais e urinárias foi observada no grupo casos comparado ao grupo controle. O tempo médio entre o início dos sintomas e o diagnóstico definitivo de endometriose foi de 5,2±6,9 anos. Comparando os dois grupos, não foram observadas diferenças significativas nas frequências alélicas e genotípicas dos polimorfismos PGR + 331C > T, CYP17A1 -34A > G e CYP19A1 1531G > A, e nem considerando os sintomas, a classificação e o estadiamento da endometriose. O genótipo combinado PGR + 331TT/CYP17A1 -34AA/CYP19A11531AA está associado positivamente com a endometriose (razão de possibilidades [RP] = 1,72; intervalo de confiança de 95% [IC95%] = 1,09-2,72). Conclusões A análise combinada dos polimorfismos PGR-CYP17A1-CYP19A1 sugere uma interação gene-gene na susceptibilidade à endometriose. Estes resultados podem contribuir para a identificação de biomarcadores para o diagnóstico e/ou prognóstico da doença, assim como de possíveis alvos moleculares para um tratamento individualizado.

Surgical Therapy of 17α-hydroxylase Deficiency in 30 Patients / 中国医学科学院学报

Objective To analyze the clinical features of 17α-hydroxylase deficiency and explore the appropriate timing and methods of surgical treatment. Methods We retrospectively analyzed the clinical data of patients with complete 17α-hydroxylase deficiency,containing Y chromosome material in their karyotype,adimitted to Peking Union Medical College Hospital from January 2004 to December 2014. Results Thirty patients with complete 17α-hydroxylase deficiency were included. Their social gender were all female and the mean age at diagnosis was (16.1±2.7) years. Twenty-six patients (86.7%) presented with primary amenorrhea and hypertension. The development of secondary sexual characteristics was poor and their uterus was absent. The levels of gonadotropin,progesterone,and adrenocorticotropic hormone were elevated in all patients and the levels of estradiol,testosterone,and cortisol were decreased. All patients had undergone laparoscopic gonadectomy. Most (86.7%) of the gonads were located in abdomen,while 13.3% were in inguinal canal. Histopathology confirmed that gonadal malignancy was obsetved in two patients (6.7%): one with leydig cell tumor and the other with sertoli cell tumor. Conclusions Patients with complete 17α-hydroxylase deficiency have specific clinical features. Early diagnosis and timely laparoscopic gonadectomy are critical to prevent gonadal malignancy.

A case of 17 alpha-hydroxylase deficiency / 대한생식의학회지

17alpha-hydroxylase and 17,20-lyase are enzymes encoded by the CYP17A1 gene and are required for the synthesis of sex steroids and cortisol. In 17alpha-hydroxylase deficiency, there are low blood levels of estrogens, androgens, and cortisol, and resultant compensatory increases in adrenocorticotrophic hormone that stimulate the production of 11-deoxycorticosterone and corticosterone. In turn, the excessive levels of mineralocorticoids lead to volume expansion and hypertension. Females with 17alpha-hydroxylase deficiency are characterized by primary amenorrhea and delayed puberty, with accompanying hypertension. Affected males usually have female external genitalia, a blind vagina, and intra-abdominal testes. The treatment of this disorder is centered on glucocorticoid and sex steroid replacement. In patients with 17alpha-hydroxylase deficiency who are being raised as females, estrogen should be supplemented, while genetically female patients with a uterus should also receive progesterone supplementation. Here, we report a case of a 21-year-old female with 17alpha-hydroxylase deficiency who had received inadequate treatment for a prolonged period of time. We also include a brief review of the recent literature on this disorder.

Congenital adrenal hyperplasia due to 17-alpha-hydoxylase/17, 20-lyase deficiency presenting with hypertension and pseudohermaphroditism: first case report from Oman

This is the first report of congenital adrenal hyperplasia [CAH] due to combined 17 alpha-hydroxylase/17, 20 lyase deficiency in an Omani patient who was initially treated for many years as a case of hypertension. CAH is an uncommon disorder that results from a defect in steroid hormones biosynthesis in the adrenal cortex. The clinical presentation depends on the site of enzymatic mutations and the types of accumulated steroid precursors. A 22-year-old woman who was diagnosed to have hypertension since the age of 10 years who was treated with anti-hypertensive therapy was referred to the National Diabetes and Endocrine Centre, Royal Hospital, Oman. The patient also had primary amenorrhea and features of sexual infantilism. Full laboratory and radio-imaging investigations were done. Adrenal steroids, pituitary function and karyotyping study were performed and the diagnosis was confirmed by molecular mutation study. Laboratory investigations revealed adrenal steroids and pituitary hormones profile in addition to 46XY karyotype that are consistent with the diagnosis of CAH due to 17 alpha-hydroxylase deficiency. Extensive laboratory workup revealed low levels of serum cortisol [and its precursors 17 alpha-hydroxyprogesterone and ll'deoxycortisol], adrenal androgens [dehydroepiandrosterone sulfate and androstenedione], and estrogen [estradiol]; and high levels of mineralocorticoids precursors [11-deoxycorticosterone and corticosterone] with high levels of ACTH, FSH and LH. Mutation analysis revealed CYP17Al-homozygous mutation [c.287G>A p.Arg96Gln] resulting in the complete absence of 17 alpha-hydroxylase/17, 20-lyase activity. The patient was treated with dexamethasone and ethinyl estradiol with cessation of anti-hypertensive therapy. A review of the literature was conducted to identify previous studies related to this subtype of CAH. This is the first biochemically and genetically proven case of CAH due to 17 alpha-hydroxylase/17, 20-lyase deficiency in Oman and in the Arab World described in the literature

Advances in the study of steroidal inhibitors of cytochrome P45017alpha / 药学学报

The steroidal enzyme cytochrome P45017alpha catalyzes the conversion of progesterone and pregnenolone into androgens, androstenedione and dehydroepiandrosterone, respectively, the direct precursors of estrogens and testosterone. Dihydrotestosterone is the principal active androgen in the prostate, testosterone is also an active stimulant of the growth of prostatic cancer tissue. Inhibition of this enzyme as a mechanism for inhibiting androgen biosynthesis could be a worthwhile therapeutic strategy for the treatment of PCA. In this paper, four categories of steroidal inhibitors of cytochrome P45017alpha will be reviewed, a diverse range of steroidal inhibitors had been synthesized and shown to be potent inhibitors of P45017alpha.

Analysis of CYP17A1 gene mutation in a child patient with 17 alpha-hydroxylase/17, 20-lyase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze CYP17A1 gene mutations in a child patient with 17 alpha-hydroxylase/17, 20-lyase deficiency (17OHD), and to review characteristics of CYP17A1 gene mutations in Chinese patients with 17OHD.</p><p><b>METHODS</b>Clinical data were collected. PCR and DNA sequencing were performed to detect mutations in the patient.</p><p><b>RESULTS</b>The patient has presented classical features of 17OHD including hypertension, hypokalemia, decreased sex hormones and plasma cortisol, and elevated blood adrenocorticotrophic hormone. A compound heterozygous mutation c.987C>A and c.985del was detected in the CYP17A1 gene, which resulted in two premature stop codons at positions 328 and 417.</p><p><b>CONCLUSION</b>A compound mutation, c.987C>A and c.985del, has been identified in a patient with 17OHD. Among CYP17A1 gene mutations identified in Chinese patients, missence mutations have been most common, and exons 5 and 8 have been the mutation hotspots.</p>

Association of single nucleotide polymorphism in CYP17 and ERα genes with endometriosis risk in southern Chinese women / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the association of single nucleotide polymorphisms in cytochrome P450 17 (CYP17) and estrogen receptor alpha (ERα ) genes with the risk of endometriosis among southern Chinese women.</p><p><b>METHODS</b>Two SNPs rs743572 (CYP17 gene 34T/C) and rs9322331 (ERα gene -397T/C) were genotyped by high resolution melting curve in 432 endometriosis patients and 499 matched controls.</p><p><b>RESULTS</b>There was no significant difference in the genotype frequencies of the two loci between endometriosis patients and the control subjects (P> 0.05). And there was no significant interaction effect of these two genes on the disease either.</p><p><b>CONCLUSION</b>CYP17 gene and ERα gene may not be genetic risk factors for endometriosis among southern women in China.</p>

Limited Expression of Cytochrome P450 17alpha-Hydroxylase/17,20-Lyase in Prostate Cancer Cell Lines

PURPOSE: Cytochrome P450 17alpha-hydroxylase/17,20-lyase (CYP17A1) is a key enzyme in the androgen biosynthesis pathway. CYP17A1 has been focused on because of the promising results of a potent CYP17A1 inhibitor in the treatment of castration-resistant prostate cancer (CRPC). A hypothesis that intratumoral androgenesis may play a role in the progression of CRPC has recently been postulated. Thus, we evaluated whether commonly used prostate cancer cell lines express CYP17A1. MATERIALS AND METHODS: Androgen-sensitive LNCaP and androgen-insensitive PC-3 and DU145 cells were used. To evaluate the expression of CYP17A1 protein and RNA, we performed Western blotting and RT-PCR, respectively. RESULTS: We were unable to detect either CYP17A1 protein or RNA in any of the cell lines tested. We failed to detect any expression of CYP17A1, despite several repetitions of these techniques under different conditions. CONCLUSIONS: The expression of CYP17A1 protein and RNA in LNCaP, PC-3, and DU145 cells appears to be either absent or too low for detection. The mechanism of action of abiraterone acetate, a CYP17A1 inhibitor, may be related more to adrenal androgen blockade than to intratumoral androgenesis.

Correlation between CYP17 gene polymorphisms and female post adolescent acne in Han population in Hunan Province / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the correlation between androgen-related CYP17 gene polymorphisms and female post adolescent acne in Han population in Hunan Province.</p><p><b>METHODS</b>The female patients with post adolescent acne and high levels of androgen (A group), those without high levels of androgen (B group) and healthy subjects (C group) were enrolled. The CYP17 gene polymorphism was investigated by PCR using DNA samples from peripheral blood lymphocytes. The T-->C transition in the risk allele (A2) produced a new recognition site for the restriction endonuclease MspA1 I. Three genotypes of androgen-related CYP17 gene (A1A1, A1A2, and A2A2) were determined and confirmed by sequencing.</p><p><b>RESULTS</b>The frequency of the A1A2 gene was similar in the cases and controls (P>0.05). The frequency of A2A2 gene was not significantly different between groups A and C (P>0.05). The frequency of A2A2 gene was significantly different between groups A and B and between groups B and C (P<0.05).</p><p><b>CONCLUSION</b>The presence of base substitution in androgen-related CYP17 gene at -34 bp (T-->C) increases the risk of post adolescent acne in female subjects with increased androgen levels.</p>

The three mechanisms underlying progesterone withdrawal in late pregnancy in mammals / 生理学报

Endocrine hormones are important factors in maintaining pregnancy as well as initiation of parturition. Progesterone is the major hormone maintaining myometrium quiescence, while glucocorticoids, prostaglandins and estrogen are among the major hormones involved in the initiation of parturition. Therefore progesterone withdrawal at the end of pregnancy is the prerequisite for the initiation of parturition. However, unlike most of the other species of mammals that the withdrawal of progesterone is achieved via reduction of progesterone synthesis or increased conversion of progesterone to estrogen, some mammals including the primates maintain high progesterone level throughout gestation and even during parturition. Accumulating lines of evidence indicate that the withdrawal of progesterone in human being is attained via the changes of the expression ratio of progesterone receptor subtypes and the changes of co-activators required for the activation of transcriptional activity of progesterone receptor. Here we reviewed the three major mechanisms, namely luteolysis, upregulation of placental P450c17 hydroxylase and changes of progesterone receptor functions, underlying progesterone withdrawal in late pregnancy in mammals.

Genetic mutation analysis of a kindred with a patient suffering from 17 alpha-hydroxylase/17, 20-lyase deficiency / 中华儿科杂志

<p><b>OBJECTIVE</b>To detect CYP17A1 gene mutation in a patient with 17 alpha-hydroxylase/17, 20-lyase deficiency and her family members.</p><p><b>METHOD</b>Genomic DNA was extracted from the blood of the patient, her parents and twin sister. The 8 exons of CYP17A1 gene were amplified with polymerase chain reaction (PCR) and screened for mutations by sequencing.</p><p><b>RESULT</b>The analysis revealed that the patient was a compound heterozygote carrying two different inherited point mutations on CYP17A1 gene. They were nt186delC on exon 1 and nt1085G > A on exon 6. This type of mutation could induce 17OHD because of complete loss of 17 alpha-hydroxylase activities. And her parents and the twin sister were carriers on CYP17A1 gene. In addition, the mutation nt186delC was a novel point mutation and it was not discovered in normal children.</p><p><b>CONCLUSION</b>A new compound heterozygote carrying two different inherited point mutations on CYP17A1 gene was found, and her parents and twin sister were carriers. This is probably the first report in the world of a twin sisters of whom one is a patient with 17OHD and the other is a carrier of CYP17A1 gene mutation.</p>

A case-control study of environmental and genetic factors and prostate cancer in Guangdong / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the etiologic relationship of prostate cancer and environmental and genetic polymorphism in southern China</p><p><b>METHODS</b>A hospital-based and 1:1 matched case-control study was conducted. A total of 142 matched pairs of subjects were investigated in this study. The blood samples were collected from 85 cases of prostate cancer and 82 controls of other diseases after informing consent. The CYP1A1, CYP17 and AR genes were analyzed by using the method of PCR, PCR-RFLP. The data were analyzed with conditional logistic regression model.</p><p><b>RESULTS</b>An increased risk of prostate cancer development was observed with the early first spermatorrhea (age < 18) (OR = 2.90, 95% CI: 1.76 - 4.80), early first sexual intercourse (age < or = 24) (OR = 2.38, 95% CI: 1.14 - 4.96), frequent sexual intercourse before 35 year old (OR = 1.80, 95% CI: 1.19 - 2.70), family history of cancer (OR = 2.70, 95% CI: 1.31 - 5.58), more intake of pork (OR =2.27, 95% CI: 1.38 - 3.70). Factors in lowing the risks were the fruit intake and drinking of green tea by OR value at 0.25 (95% CI: 0.08 - 0.75) and 0.52 (95% CI: 0.28 -0.96) respectively. CYP17 A1/A2 and CYP17 A2/A2 genotypes were related with a high risk of prostate cancer and OR values of 1.78 (95% CI: 0.70 - 4.53) and 2.57 (95% CI: 0.91 - 7.25) respectively. Study also showed that there was an interaction between CYP17 polymorphisms and early first spermatorrhea and family cancer history related to the risk of prostate cancer with OR value at 13.35 (95% CI: 1.58 - 113.00) and 4.01 (95% CI: 1.22 - 13.17) respectively.</p><p><b>CONCLUSION</b>Sexual intercourse, dietary intake and family cancer history should be related to prostate cancer occurrence. CYP17 polymorphism might be associated with a high risk of prostate cancer. It suggests that there are multiple environmental and genetic factors to the prostate cancer.</p>

Clinical and molecular genetic analysis for 7 patients from 5 pedigrees with 17a-hydroxylase/17, 20 lyase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the clinical and genetic characteristics of 7 patients from 5 families with 17a-hydroxylase/17,20 lyase deficiency (17OHD) and the CYP17A1 mutation in Chinese.</p><p><b>METHODS</b>Clinical features and laboratory data were collected from 5 families with 17OHD. PCR direct sequencing was performed to screen the mutation of CYP17A1 gene of the patients. Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) and sequencing were performed to screen the mutations of CYP17A1 gene in 288 healthy individuals from Shandong province.</p><p><b>RESULTS</b>Seven patients (5 of them were 46,XX; 2 were 46,XY) had typical clinical presentation of sexual infantilism, hypertension and hypokalemia. Hormone profile indicated decreased plasma cortisol and sex hormones, and elevated blood adrenocorticotrophic hormone (ACTH). TAC329AA and H373L in exon 6 and D487_F489del in exon 8 were identified from the patients. One heterozygote for D487_F489del was identified in 288 healthy controls.</p><p><b>CONCLUSION</b>The TAC329AA and D487_F489del of the CYP17A1 gene were the most frequent mutations in Chinese with 17OHD.There might be certain frequency of heterozygotes for D487_F489del in Chinese population.</p>

Relationship between estrogen-biosynthesis gene (CYP17, CYP19, HSD17beta1) polymorphisms and breast cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the relationship between the polymorphism of estrogen-biosynthesis genes (CYP17, CYP19, HSD17beta1) and risk of breast cancer.</p><p><b>METHODS</b>A matched case-control study was designed. From May 2007 to July 2008, 200 pairs of subjects with and without breast cancer were enrolled, who were matched by age and menstruation status. Demographical characteristics, dietary factors and reproductive factors were investigated by questionnaire. CYP17 locus 1931 (T-->C), CYP19 codon 264 (Arg-->Cys) and HSD17beta1 locus 1954 (A-->G) were identified by AS-PCR (allele-specific PCR). The gene-gene interaction were analyzed with the MDR model (multifactor dimensionality reduction). Based on the results of MDR model, an unconditional logistic regression model was simulated to estimate the ORs of interaction factors and other risk factors.</p><p><b>RESULTS</b>The main effect of CYP17, CYP19 and HSD17beta1 susceptible genotypes were not correlated to breast cancer (OR approximately 1, P > 0.05). The positive interaction effect between CYP17 (T 1931C) and HSD17beta1 (A1954G) was discovered by MDR model with a statistically significant difference (Sign test, P = 0.05). The model's testing balance accuracy was 56.00%, and crossing validation consistency was 10/10. Multivariable unconditional logistic regression showed that after adjusting BMI, intake of estrogen, age of first birth, number of abortion and period of breast feeding, the interaction item of CYP17 (T1931C) and HSD17beta1 (A1954G) was strongly and positively correlated to breast cancer (OR = 2.52, 95%CI = 1.54 to 4.11).</p><p><b>CONCLUSION</b>The estrogen-biosynthesis genes CYP17 (T1931C) and HSD17beta1 (A1954G) polymorphism may jointly increase the risk of breast cancer.</p>

Association study of the oestrogen signalling pathway genes in relation to age at natural menopause.

Genetic factors play a significant role in influencing the variation of age at natural menopause (AANM). Estrogen receptor beta (ESR2), is an important factor in the mechanism of action of estrogen, while the aromatase gene (CYP19) and the 17-alpha-hydroxylase gene (CYP17) are involved in the biosynthesis of estrogen. We tested whether polymorphisms of ESR2, CYP19 and CYP17 genes are associated with AANM in Caucasian females. A total of 52 SNPs (17 for ESR2, 28 for CYP19, and 7 for CYP17) were successfully genotyped for 229 Caucasian women having experienced natural menopause. Comprehensive statistical analyses focusing on the association of these genes with AANM were conducted. The effects of age, height and age at menarche on AANM were adjusted when conducting association analyses. We found that six SNPs (2, 6-7, 9, 13 and 16) within ESR2 were not significantly associated with AANM after Bonferroni correction. However, two blocks of ESR2 were associated with AANM. For CYP19, two SNPs (24 and 27) were nominally associated with AANM. No significant association was observed between CYP17 and AANM. Our results suggest that genetic variation in the ESR2 and CYP19 genes may influence the variation in AANM in Caucasian women.

New compound heterozygous mutation causes partial combined 17 alpha-hydroxylase/17,20-lyase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the CYP17A1 gene mutations in a Chinese 46,XX patient with partial combined 17 alpha-hydroxylase/17,20-lyase deficiency.</p><p><b>METHODS</b>Clinical data were retrospectively analyzed. The genomic DNA of the patient and her parents was isolated from whole blood. Seven pairs of primers were used to amplify eight exons and exon-intron boundaries of the CYP17A1 gene. The amplified PCR products were purified by agarose gel and then directly sequenced. In order to confirm the DNA sequences of different alleles, some fragments were inserted into pMD 18-T vector and then subclone sequenced. Sequencing results were compared to the established human CYP17A1 sequence.</p><p><b>RESULTS</b>The patient was new compound heterozygous of 5994-5995 delAT/7541 C>T. The mutation 5994-5995 del AT, causing amino acid I259H, 274X, was proposed to result early truncated protein which was lack of the activity center site of P450C17, whereas missense mutation 7541 C>T causing A398V did not lie in the active site of the enzyme according to the computer model of human P450C17. The 46, XX case had irregular menstruation and slightly hypertension and hypokalemia. The ACTH stimulating test as well as the result of the sex hormones suggested that there was partial 17 alpha-hydroxylase/17, 20-lyase enzyme activities in the adrenal and sexual gland. We speculate that A398V might conserve partial of the enzyme's activities. The genotype was coincident with phenotype.</p><p><b>CONCLUSION</b>More study should be done to have better understanding of the function of the mutated P450C17 enzymes.</p>

CYP1A1 and CYP2E1 polymorphism frequencies in a large Brazilian population

The enzymes encoded by the polymorphic genes CYP1A1 and CYP2E1 play an important role in the activation and inactivation of xenobiotics. These enzymes have been associated with xenobiotic-induced diseases, such as cancer, therapeutic failure and adverse effects of drugs. The aim of the present study was to determine the allelic and genotypic frequencies of these polymorphisms in a large, ethnically mixed Brazilian population sample from Rio de Janeiro. Polymorphisms CYP1A1 and CYP2E1 were determined in 870 unrelated individuals by PCR-RFLP analysis in peripheral blood DNA. The observed allelic frequencies were 0.90 for CYP1A1*1A and 0.95 for CYP2E1*1A, in the total sample. The allelic frequency of CYP1A1*2C in "pardos" (0.13) and Brazilian whites (0.11) was higher than in Caucasians (0.05), which may be a result of the Amerindian genetic component, that presents the highest frequency of this allele observed up to now. The genotype distributions for both polymorphisms were in Hardy-Weinberg equilibrium and were statistically different between males and females, and among ethnic groups.