The R453Q and D151A polymorphisms of hexose-6-phosphate dehydrogenase gene (H6PD) influence the polycystic ovary syndrome (PCOS) and obesity.

Hexose-6-phosphate dehydrogenase (H6PDH) influences 11ß-hydroxysteroid dehydrogenase activity, a key enzyme in the peripheral metabolism of cortisol that modulates insulin sensitivity in adipose tissue. To study the associations of R453Q and D151A polymorphisms in the H6PDH gene (H6PD) with polycystic ovary syndrome (PCOS) and their influence on clinical and metabolic variables, we genotyped 237 patients with PCOS and 135 control women for the R453Q (rs6688832) and D151A (rs34603401) variants in H6PD. The R453Q genotypes were distributed differently in patients and controls (χ(2)=9.55, P=0.002). Genotypes of D151A were distributed evenly in women with PCOS and controls, but showed a different distribution in non-obese and obese women (χ(2)=3.95, P=0.047), especially within the PCOS subgroup (χ(2)=4.65, P=0.031). A backward stepwise likelihood ratio logistic regression model (Nagelkerke's R(2)=0.490; χ(2)=164; P<0.0001) retained free testosterone (OR=1.13; 95% CI: 1.10-1.17) and H6PD Q453 alleles (OR=0.46; 95% CI: 0.27-0.79) as statistically significant predictors for PCOS, whereas homeostasis model assessment of insulin resistance and the H6PD D151A variant were excluded by the model. Both H6PD variants were associated with several phenotypic variables, including fasting insulin, homeostasis model assessment of insulin resistance and androstenedione levels. In summary, the R453Q and D151A variants of the H6PD gene are associated with PCOS and obesity, respectively, and may contribute to the PCOS phenotype by influencing obesity, insulin resistance and hyperandrogenism.

Adiponectin and resistin in PCOS: a clinical, biochemical and molecular genetic study.

BACKGROUND: We conducted a cross-sectional case-control study to evaluate the possible involvement of adiponectin and resistin in the pathogenesis of polycystic ovary syndrome (PCOS). METHODS: Seventy-six PCOS patients and 40 non-hyperandrogenic women matched for BMI and degree of obesity were included. Serum adiponectin and resistin levels, anthropometrical and hormonal variables, the 45 T-->G and 276 G-->T polymorphisms in the adiponectin gene, and the -420 C-->G variant in the resistin gene, were analysed. RESULTS: Serum adiponectin concentrations were reduced in PCOS patients compared with controls (P = 0.038) irrespective of the degree of obesity, whereas serum resistin levels were increased in overweight and obese women compared with lean subjects (P = 0.016), irrespective of their PCOS or controls status. The adiponectin and resistin polymorphisms were not associated with PCOS and did not influence serum levels of adiponectin, resistin and other clinical and hormonal variables. In a multiple regression model, the waist-to-hip ratio, free testosterone levels and age, but not insulin resistance, were the major determinants of hypoadiponectinaemia. CONCLUSIONS: PCOS patients present with hypoadiponectinaemia, in relation with abdominal adiposity and hyperandrogenism. Our present results suggest that hyperandrogenism and abdominal obesity, by reducing the serum levels of the insulin sensitizer adipokine adiponectin, might contribute to the insulin resistance of PCOS.

Obesity, and not insulin resistance, is the major determinant of serum inflammatory cardiovascular risk markers in pre-menopausal women.

AIMS/HYPOTHESIS: Increased serum inflammatory markers have been found in obesity and insulin-resistant states, and could play a causative role in insulin resistance, atherosclerosis and cardiovascular disease. The polycystic ovary syndrome represents a human model of insulin resistance because both lean and obese polycystic ovary syndrome patients are insulin-resistant compared with non-hyperandrogenic women. We evaluated whether obesity, insulin resistance, or both, are related to the increased concentrations of inflammatory markers in pre-menopausal women. METHODS: We compared 35 patients with polycystic ovary syndrome and 28 healthy women, paired for BMI, prevalence of obesity and smoking. Measurements included serum inflammatory markers, BMI, waist-to-hip ratio, blood pressure, serum glucose, insulin, lipid and hormone concentrations, and insulin sensitivity index. RESULTS: The insulin sensitivity index was reduced in polycystic ovary syndrome patients compared with controls. However, no differences were observed between both groups in C-reactive protein, interleukin 6, tumour necrosis factor-alpha, soluble type 2 tumour necrosis factor receptor, and soluble intercellular cell adhesion molecule-1. When considering patients and controls as a whole, C-reactive protein and interleukin 6, were increased in obese subjects compared with lean women. Inverse correlations existed between insulin sensitivity index and C-reactive protein, interleukin 6, tumour necrosis factor-alpha, soluble type 2 tumour necrosis factor receptor, and soluble intercellular cell adhesion molecule-1. Only the weak correlation with C-reactive protein persisted after controlling for BMI. CONCLUSION/INTERPRETATION: Obesity, and not insulin resistance, is the major determinant of serum inflammatory cardiovascular risk markers in pre-menopausal women.

Receiver operating characteristic analysis of the performance of basal serum hormone profiles for the diagnosis of polycystic ovary syndrome in epidemiological studies.

OBJECTIVE: We have used receiver operating characteristic (ROC) analysis to determine the diagnostic performance of several serum parameters, in order to evaluate their potential usefulness in establishing the diagnosis of polycystic ovary syndrome (PCOS) in epidemiological studies. DESIGN: Prospective study. METHODS: One hundred and fourteen women reporting spontaneously for blood donation were included in the study. Menopausal and oral contraceptive-treated women were excluded. Serum samples were obtained at the moment of donation, independently of fasting, time of day or day of menstrual cycle. Measurements included total testosterone, sex hormone-binding globulin (SHBG), dehydroepiandrosterone sulfate (DHEAS), LH, FSH and estradiol. The free testosterone (FT) concentration and the free androgen index (FAI) were calculated from testosterone and SHBG levels. ROC curves were calculated for all these serum determinations. RESULTS: Eight patients were diagnosed with PCOS, according to the presence of oligomenorrhea, hirsutism, acne and/or hyperandrogenemia, and exclusion of non-classic congenital adrenal hyperplasia, hypothyroidism and hyperprolactinemia. Of the parameters studied SHBG, FAI, FT and DHEAS were considered adequate measures for the diagnosis of PCOS. For example, serum SHBG levels showed an area under the ROC curve of 0.875+/-(S.E.(w))0.045 (95% confidence interval 0.800-0.929). A SHBG decision threshold <37 nmol/l had a sensitivity of 87.5%, a specificity of 86.8%, a positive likelihood ratio of 6.63, and a negative likelihood ratio of 0.14, for the diagnosis of PCOS. CONCLUSIONS: Our present results strongly suggest that decreased SHBG levels, and increased FAI, free testosterone concentration and DHEAS concentrations, are highly effective as single analytical procedures in epidemiological studies for the detection of PCOS in women of reproductive age.

Differential developmental regulation and functional effects on pre-TCR surface expression of human pTalpha(a) and pTalpha(b) spliced isoforms.

Functional rearrangement at the TCRbeta locus leads to surface expression on developing pre-T cells of a pre-TCR complex composed of the TCRbeta-chain paired with the invariant pre-TCRalpha (pTalpha) chain and associated with CD3 components. Pre-TCR signaling triggers the expansion and further differentiation of pre-T cells into TCRalphabeta mature T cells, a process known as beta selection. Besides the conventional pTalpha transcript (termed pTalpha(a)), a second, alternative spliced, isoform of the pTalpha gene (pTalpha(b)) has been described, whose developmental relevance remains unknown. In this study, phenotypic, biochemical, and functional evidence is provided that only pTalpha(a) is capable of inducing surface expression of a CD3-associated pre-TCR complex, which seems spontaneously recruited into lipid rafts, while pTalpha(b) pairs with and retains TCRbeta intracellularly. In addition, by using real-time quantitative RT-PCR approaches, we show that expression of pTalpha(a) and pTalpha(b) mRNA spliced products is differentially regulated along human intrathymic development, so that pTalpha(b) transcriptional onset is developmentally delayed, but beta selection results in simultaneous shutdown of both isoforms, with a relative increase of pTalpha(b) transcripts in beta-selected vs nonselected pre-T cells in vivo. Relative increase of pTalpha(b) is also shown to occur upon pre-T cell activation in vitro. Taken together, our data illustrate that transcriptional regulation of pTalpha limits developmental expression of human pre-TCR to intrathymic stages surrounding beta selection, and are compatible with a role for pTalpha(b) in forming an intracellular TCRbeta-pTalpha(b) complex that may be responsible for limiting surface expression of a pTalpha(a)-containing pre-TCR and/or may be competent to signal from a subcellular compartment.

TNF-alpha and hyperandrogenism: a clinical, biochemical, and molecular genetic study.

To evaluate the role of TNF-alpha in the pathogenesis of hyperandrogenism, we have evaluated the serum TNF-alpha levels, as well as several polymorphisms in the promoter region of the TNF-alpha gene, in a group of 60 hyperandrogenic patients and 27 healthy controls matched for body mass index. Hyperandrogenic patients presented with mildly increased serum TNF-alpha levels as compared with controls (mean[median] +/- SD: 7.2[7.0] +/- 3.3 pg/ml vs. 5.6[4.4] +/- 4.0 pg/ml, P < 0.02). Although no differences in body mass index and insulin resistance indexes were observed between patients and controls, when subjects were classified by body weight, serum TNF-alpha was increased only in lean patients as compared with lean controls, but this difference was not statistically significant when comparing obese patients with obese controls. The TNF-alpha gene polymorphisms studied here (-1196C/T, -1125G/C, -1031T/C, -863C/A, -857C/T, -316G/A, -308G/A, -238G/A, and -163G/A) were equally distributed in hyperandrogenic patients and controls. However, carriers of the -308A variant presented with increased basal and leuprolide-stimulated serum androgens and 17-hydroxyprogesterone levels when considering patients and controls as a group. No differences were observed in serum TNF-alpha levels, body mass index, and insulin resistance indexes, depending on the presence or absence of these variants. In conclusion, our present results suggest that the TNF-alpha system might contribute to the pathogenesis of hyperandrogenism, independent of obesity and insulin resistance. However, elucidation of the precise mechanisms underlying the relationship between the TNF-alpha system and androgen excess is needed before considering TNF-alpha as a significant contributing factor to the development of hyperandrogenism.

Role of the follistatin gene in women with polycystic ovary syndrome.

OBJECTIVE: To search for mutations in the coding exons of the follistatin gene of women diagnosed with polycystic ovary syndrome (PCOS). DESIGN: Controlled clinical study. SETTING: Tertiary institutional hospital. PATIENT(S): Thirty-four women diagnosed with PCOS and 15 healthy control women. INTERVENTION(S): Whole blood and serum samples were collected during the follicular phase of the menstrual cycle. MAIN OUTCOME MEASURE(S): Circulating total testosterone (T), sex hormone-binding globulin (SHBG), calculated free T (FT), androstenedione (A), dehydroepiandrosterone-sulfate (DHEAS), LH, FSH, E2, and basal and adenocorticotropic hormone (ACTH)-stimulated 17-hydroxyprogesterone (17-OHP) were determined. Insulin resistance was estimated from fasting glucose and insulin levels, using the homeostasis model assessment. The coding regions of the follistatin gene were studied by heteroduplex analysis after polymerase chain reaction amplification. RESULT(S): Women with PCOS presented with higher body-mass index, insulin resistance, T, FT, A, and ACTH-stimulated 17-OHP serum concentrations and lower SHBG serum levels, as compared with controls. No differences were observed among the groups in serum DHEAS, basal 17-OHP, E(2), LH, and FSH. No mutations were found in coding regions of the follistatin gene, with the exception of a G to A change at cDNA position 951, resulting in a silent mutation. This change was present in 2 (5.9%) of 34 patients and 1 (6.7%) of 15 controls. CONCLUSION(S): Mutations in the coding regions of the follistatin gene do not appear to be related to PCOS.

Role of the pentanucleotide (tttta)(n) polymorphism in the promoter of the CYP11a gene in the pathogenesis of hirsutism.

OBJECTIVE: To determine if the (tttta)(n) repeat polymorphism in the promoter region of CYP11a gene is associated with hirsutism and hyperandrogenism in women from Spain. DESIGN: Controlled clinical study. SETTING: Tertiary-care institutional hospital. PATIENT(S): Ninety-two hirsute women and 33 healthy control women. INTERVENTION(S): Basal and adrenocorticotropin-stimulated serum samples and genomic DNA extracted and purified from whole-blood samples were obtained during the follicular phase of the menstrual cycle. MAIN OUTCOME MEASURE(S): CYP11a (tttta)(n) repeat-polymorphism genotype and serum ovarian and adrenal androgen levels. RESULT(S): None of the CYP11a (tttta)(n) polymorphic alleles was associated with hirsutism. The absence of the four-repeat-units allele (4R-- genotype), which has been reported by other authors to be associated with polycystic ovary syndrome (PCOS), was found in 22.4% of the women studied here and was equally distributed among patients and controls, independently of the presence of PCOS and/or ovarian or adrenal hyperandrogenism. No differences were observed in serum hormone concentrations in 4R-- individuals as compared with subjects with at least one four-repeat-units allele. CONCLUSION(S): The (tttta)(n) repeat polymorphism in the promoter region of CYP11a does not appear to play any significant role in the pathogenesis of hirsutism and hyperandrogenism in women from Spain.

Screening for mutations in the steroidogenic acute regulatory protein and steroidogenic factor-1 genes, and in CYP11A and dosage-sensitive sex reversal-adrenal hypoplasia gene on the X chromosome, gene-1 (DAX-1), in hyperandrogenic hirsute women.

Abstract Abnormalities in adrenal and/or ovarian steroidogenesis are found in most patients with hirsutism. The rate-limiting step in the synthesis of steroids in the ovary and the adrenal is the conversion of cholesterol into pregnenolone by cholesterol side-chain cleavage enzyme (P450scc), encoded by the gene CYP11A, after cholesterol is introduced into the mitochondria by the steroidogenic acute regulatory protein (StAR). DAX-1 is a repressor of StAR gene expression, and steroidogenic factor-1 (SF-1) is a regulator of CYP11A, DAX-1, and StAR gene. Mutations in any of these factors resulting in gain of function, or loss of repression, of StAR or P450scc might contribute to the steroidogenic abnormalities present in hirsute patients. In the present study we have screened, using heteroduplex analysis, the genes encoding StAR and SF-1 as well as DAX-1 and CYP11A for mutations in genomic DNA from 19 women presenting with hirsutism and increased serum androgen levels. When variants were found, analysis was extended to a larger group of hyperandrogenic patients and nonaffected women. Two variants were identified in the SF-1 gene. A G-->C change in exon 6, resulting in an Arg(365)Pro mutation, was found in 1 of 45 patients, but not in controls. Also, a Gly(146)Ala missense mutation, resulting from a G-->C change in exon 4, was found in 2 of 48 patients and in 2 of 50 nonaffected individuals. We identified a C-->T base pair change at position -33 of the StAR gene. Three of 48 patients and 3 of 43 controls presented this variant. No mutations were found in coding regions of the StAR gene. Analysis of CYP11A-coding regions identified a G-->A change in exon 3, resulting in a Val(179)Ile missense mutation. This mutation was found in 1 of 29 patients studied and was not present in 50 controls. Finally, analysis of DAX-1 showed no variant in any of the women studied. In conclusion, mutations in StAR, SF-1, CYP11A, and DAX-1 are seldom found in hirsute patients and do not explain the steroidogenic abnormalities found in these women.

A prospective study of the prevalence of the polycystic ovary syndrome in unselected Caucasian women from Spain.

We prospectively estimated the prevalence of the polycystic ovary syndrome (PCOS), as defined by the NIH/NICHHD 1990 endocrine criteria, in a population of 154 Caucasian women of reproductive age reporting spontaneously for blood donation. Anthropometric data; the presence of hirsutism, acne, and androgenic alopecia; and the menstrual history were recorded by a single investigator. In 145 women, blood samples were also obtained for measurement of serum androgen levels. PCOS was defined by the presence of 1) oligomenorrhea, 2) clinical and/or biochemical hyperandrogenism, and 3) exclusion of hyperprolactinemia, thyroid disorders, and nonclassic 21-hydroxylase deficiency. Hirsutism was defined by a modified Ferriman-Gallwey score of 8 or more, acne was considered as a sign of hyperandrogenism when persistent after the second decade of life, and hyperandrogenemia was defined by an increase in circulating testosterone or dehydroepiandrosterone sulfate or an increase in the free androgen index above the 95th percentile of the control values derived from the nonhirsute, nonacneic women having regular menses who were not receiving hormonal therapy. PCOS was present in 10(6.5%), hirsutism was present in 11 (7.1%), and acne was present in 19 (12.3%) of the 154 women. Our results demonstrate a 6.5% prevalence of PCOS, as defined, in a minimally biased population of Caucasian women from Spain. The polycystic ovary syndrome, hirsutism, and acne are common endocrine disorders in women.

[Heterozygosity loss and somatic mutations in type I and II dominant autosomal renal polycystic kidney disease: evidence of a recessive mechanism at a cell level in cystogenesis]. / Estudio de pérdidas de heterozigosidad y mutaciones somáticas en la poliquistosis renal autosómica dominante tipos I y II: demostración de un mecanismo recesivo a nivel celular en la cistogénesis.

Autosomal dominant polycystic kidney disease (ADPKD) is a systemic disorder mainly characterized by renal cyst formation. Cysts in ADPKD are focal in nature, since only a small fraction of nephrons become cystic. The hypothesis that a second hit may be required for cyst formation has been proposed. This hypothesis suggests that inactivation of the inherited wild-type allele by a somatic mutation triggers cyst formation. In some cases, this second hit eliminates the normal allele and the affected cells remain with a single allele, which is the inherited mutated copy, and we only visualize one allele after the amplification by polymerase chain reaction; this is called loss of heterozygosity (LOH). In this study we have analysed the DNA isolated from epitehlial cells from 164 cysts of 8 kidneys affected by ADPKD type I and 30 cysts form a kidney affected by ADPKD type II. We have demonstrated the presence of LOH in 20.1% of PKD1 cysts and in 10% of PKD2 cysts. We have also found eight other different mutations in PKD2 cysts without LOH; so the percentage of somatic mutations in the PKD2 kidney reaches 36.6% of cysts. In conclusion, our data suggest that a recessive mechanism at the cellular level is implicated in cyst formation in the PKD1 and the PKD2 disease. The loss of both copies of the gene triggers the proliferation of a single cell, resulting in the cyst formation.

[Mutational analysis of the PKD1 and PKD2 (type 1 and 2 dominant autosomal polycystic kidney) genes]. / Estudio mutacional de los genes PKD1 y PKD2 (poliquistosis renal autosómica dominante tipo 1 y 2).

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease. It is caused by mutations in at least two different genes: PKD1 and PKD2. The study of mutations in these genes is very difficult nowadays. In this study we have analyzed the non reiterated region of the PKD1 gene and all the exons and intron exon boundaries of the PKD2 gene. The technique used to study these genes have been single strand conformation analysis and heteroduplex. We have found 25 differences within the DNA sequence of the PKD1 gene with respect to the published sequence. Seven of these changes correspond to nonsense, missense, frameshifting and splicing mutations. The rest of changes correspond to polymorphisms or rare DNA variants. In the PKD2 gene we have identified 8 new mutations and one polymorphism. Six of these mutations are frameshifting, one is missense and the other one is a large deletion of the PKD2 gene. The rate of mutation detection within the PKD1 gene has been 4% and the rate for PKD2 has been 100%. We have not observed any correlation between genotype and phenotype either in the PKD1 nor in the PKD2 gene. The mutation analysis of ADPKD genes is very difficult, specially for the PKD1 gene. The rate of mutation detection is higher in the PKD2 gene but the global efficacy of the technique is very low as PKD2 represents only 15% of ADPKD patients. Nowadays linkage analysis is still the most useful technique for the molecular diagnosis of ADPKD patients.

Location of mutations within the PKD2 gene influences clinical outcome.

BACKGROUND: Since the cloning of the gene for autosomal dominant polycystic kidney disease type 2 (PKD2), approximately 40 different mutations of that gene have been reported to be associated with the disease. The relationship between the PKD2 genotype and phenotype, however, remains unclear. METHODS: Detailed clinical information was collected for PKD2 families in which the underlying mutation had been identified. Logistic regression analysis was employed to assess the influence of age and sex on hypertension, hematuria, renal calculi, and urinary tract infections, and a clinical phenotype score was computed. Patients were then grouped according to the relative location of their mutation within the cDNA sequence, and differences in the mean phenotypic score between groups were tested for statistical significance by means of a multiple pairwise t-test. RESULTS: While phenotypic scores for each mutational group revealed a considerable degree of intragroup variability, the variability in phenotypic scores was significantly higher between mutational groups than within groups. A group-wise comparison of the mean phenotypic scores confirmed the observation of significant nonlinear variation in disease severity, with high- and low-scoring mutational groups interspersed along the gene sequence. CONCLUSION: The identification of groups of mutations in the PKD2 gene, which differ significantly with respect to clinical outcome, is to our knowledge the first description of a genotype/phenotype correlation in autosomal dominant polycystic kidney disease. It also provides evidence against complete loss of function of the mutant PKD2 gene product.

The role of the CAG repeat polymorphism in the androgen receptor gene and of skewed X-chromosome inactivation, in the pathogenesis of hirsutism.

The human androgen receptor (AR) gene contains a variable number of CAG repeats within exon 1. Shorter AR alleles, by increasing transactivation, may result in augmented AR-mediated sensitivity of the hair follicle. We have evaluated whether the number of CAG repeats, or if skewed inactivation of X-chromosome, favoring the presence of shorter AR alleles, influence hirsutism in women with and without hyperandrogenemia. Twenty-eight women with idiopathic hirsutism (normal serum androgens), 34 women with hyperandrogenic hirsutism (increased serum androgens), and 15 healthy control women were analyzed by evaluating the number of CAG repeats in genomic DNA, as well as the methylation pattern (after DNA digestion with HpaII), which allows identification of which allele is inactive. Despite marked differences among the groups in serum androgens, which were markedly increased in women with hyperandrogenic hirsutism as compared with women with idiopathic hirsutism and to controls, there were no significant differences among the groups in the number of CAG repeats. Moreover, skewed X-chromosome inactivation was found in 10 subjects (3 with idiopathic hirsutism, 5 with hyperandrogenic hirsutism, and 2 controls; P = 0.746) of the 67 women (14.9%) who were heterozygous for the AR gene. In several of these subjects, it was the shorter allele that was preferentially inactivated. In conclusion, neither the CAG repeat polymorphism in the AR gene, nor skewed X-chromosome inactivation, seem to play a significant role in the pathogenesis of hirsutism.

Estudio de pérdidas de heterozigosidady mutaciones somáticas en la poliquistosis renal autosómica dominante tipos I y II: demostración de un mecanismo recesivo a nivel celular en la cistogénesis / Loss of heterozygosity and somatic mutations in autosomal dominant polycystic kidney disease types I and II. Demonstration of a recessive mechanism at the cellular level in cyst formation

La poliquistosis renal autosómica dominante (PARAD) es una enfermedad sistémica caracterizada por la formación de quistes renales. La enfermedad muestra una expresión focal, dado que los quistes renales derivan de menos del 1 por ciento de todas las nefronas. Se ha propuesto un modelo de cistogénesis que se iniciaría con la inactivación del alelo normal del gen por una segunda mutación producida a nivel somático. Cuando esta segunda mutación es una deleción amplia que elimina la zona donde se encuentra el microsatélite utilizado como marcador, al amplificar el DNA por reacción en cadena de la polimerasa no obtenemos ningún producto y se visualizará una única banda correspondiente al alelo que contiene la mutación germinal; esto se conoce como pérdida de heterozigosidad (LOH, loss of heterozygosity).En este estudio hemos analizado el DNA extraído de células epiteliales procedentes de 164 quistes de ocho riñones de pacientes con PARAD tipo PKD1 y 30 quistes de un riñón procedente de un paciente con PARAD tipo PKD2. Se ha demostrado la presencia de LO¡'-1 en el 20,1 por ciento de los quistes PKD1 y en el 10 por ciento de los quistes PKD2. Asimismo, en el resto de quistes PKD2 hemos detectado ocho mutaciones diferentes que no cursan como LO,, con lo que el porcentaje total de mutaciones somáticas en el riñón PKD2 ha sido del 36,6 por ciento. En conclusión, estos datos sugieren que un mecanismo recesivo a nivel molecular está implicado en el proceso de cistogénesis tanto en PKD1 como en PKD2. La pérdida de ambas copias del gen provoca la proliferación a partir de una célula determinada resultando en la formación de un quiste (AU)

Estudio mutacional de los genes PKD1y PKD2 (poliquistosis renal autosómica dominante tipo 1 y 2) / Mutational analysis of PKD1 y PKD2 genes (autosomal dominant polycystic disease type 1 and 2)

La poliquistosis renal autosómica dominante (PQRAD) es la enfermedad renal hereditaria más frecuente. Es causada por mutaciones en al menos 2 genes: PKD1 y PKD2. El estudio molecular directo, mediante el análisis de mutaciones resulta actualmente complejo. En el presente trabajo hemos analizado una región de la zona no repetida del gen PKD1 y todos los exones y regiones intrónicas flanqueantes del gen PKD2. Las técnicas utilizadas han sido SSCA (single strand conformation analysis) y heteroduplex. Durante el presente estudio se han hallado 25 diferencias en la secuencia de ADN del gen PKD1 respecto a la secuencia publicada. Siete de ellas corresponden a mutaciones de tipo sin sentido, de sentido erróneo, cambio de pauta de lectura o de splicing y el resto son polimorfismos. Por lo que respecta al gen PKD2 hemos hallado 8 nuevas mutaciones y un polimorfismo, todos ellos no descritos previamente. Seis de las mutaciones modifican la pauta de lectura, una es de tipo sentido erróneo y otra es una gran deleción del gen PKD2. La tasa de detecciones para PKD1 ha sido del 4 por ciento mientras que para PKD2 ha sido del 100 por ciento. No se ha observado correlación genotipo-fenotipo para PKD1 ni para PKD2.El análisis mutación el de la PQRAD es complejo, sobre todo el del gen PKD1. El rendimiento del estudio de mutaciones es superior en el gen PKD2 pero la eficacia global es baja pues la prevalencia de la forma PKD2 es tan sólo de un 15 por ciento del total de poliquistosis. En la actualidad el análisis de ligamiento continúa sien-do la principal herramienta a utilizar para realizar el diagnóstico molecular de la enfermedad (AU)

The presence of the 21-hydroxylase deficiency carrier status in hirsute women: phenotype-genotype correlations.

OBJECTIVE: To determine the role of heterozygosity for mutations in the 21-hydroxylase gene (CYP21) in the pathogenesis of hyperandrogenism. DESIGN: Controlled clinical study. SETTING: Tertiary care institutional hospital. PATIENT(S): Forty hirsute women and 13 healthy control women. INTERVENTION(S): The source of androgen excess was determined by the changes in serum testosterone levels in response to a single 3.75-mg i.m. dose of triptorelin. MAIN OUTCOME MEASURE(S): CYP21 molecular genetic analysis and serum 17-hydroxyprogesterone levels. RESULT(S): Eight patients and one control were heterozygous carriers of CYP21 mutations. Two patients with adrenal hyperandrogenism and one patient with ovarian hyperandrogenism, who carried the V281L mutation had an increased ACTH-stimulated 17-hydroxyprogesterone level (>4.1 ng/mL) that persisted during gonadal suppression. Another patient with adrenal hyperandrogenism carried the V281L mutation, and her ACTH-stimulated 17-hydroxyprogesterone level was elevated only during gonadal suppression. Four patients (three with idiopathic hirsutism, one with ovarian hyperandrogenism) and one control were carriers of CYP21 mutations typically associated with classic congenital adrenal hyperplasia but had normal basal and ACTH-stimulated 17-hydroxyprogesterone levels. Nine patients without CYP21 mutations had increased ACTH-stimulated 17-hydroxyprogesterone levels; these decreased to normal in six of the patients during gonadal suppression. CONCLUSION(S): The response of serum 17-hydroxyprogesterone to ACTH does not predict CYP21 carrier status. No clear concordance was found between the CYP21 genotype and the functional origin of androgen excess.

A loss-of-function model for cystogenesis in human autosomal dominant polycystic kidney disease type 2.

Autosomal dominant polycystic kidney disease (ADPKD) is genetically heterogeneous, with at least three chromosomal loci (PKD1, PKD2, and PKD3) that account for the disease. Mutations in the PKD2 gene, on the long arm of chromosome 4, are expected to be responsible for approximately 15% of cases of ADPKD. Although ADPKD is a systemic disease, it shows a focal expression, because <1% of nephrons become cystic. A feasible explanation for the focal nature of events in PKD1, proposed on the basis of the two-hit theory, suggests that cystogenesis results from the inactivation of the normal copy of the PKD1 gene by a second somatic mutation. The aim of this study is to demonstrate that somatic mutations are present in renal cysts from a PKD2 kidney. We have studied 30 renal cysts from a patient with PKD2 in which the germline mutation was shown to be a deletion that encompassed most of the disease gene. Loss-of-heterozygosity (LOH) studies showed loss of the wild-type allele in 10% of cysts. Screening of six exons of the gene by SSCP detected eight different somatic mutations, all of them expected to produce truncated proteins. Overall, >/=37% of the cysts studied presented somatic mutations. No LOH for the PKD1 gene or locus D3S1478 were observed in those cysts, which demonstrates that somatic alterations are specific. We have identified second-hit mutations in human PKD2 cysts, which suggests that this mechanism could be a crucial event in the development of cystogenesis in human ADPKD-type 2.