Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.11.1.8 (thyroid peroxidase)
3,116 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In 118 successive infertile women (aged 22-40 years, median 30 years) with longstanding infertility from our infertility clinic we performed an endocrinological (TRH-test, TT3, TT4, TBG, antibodies) as well as a morphological thyroid examination (sonography and 99mTc-scintigraphy. The same endocrinological investigations except TRH-test and a thyroid sonography was performed in the control group (50 fertile women, aged 24-39 years, median 33 years). Two patients were hyperthyroid and one patient had primary hypothyroidism. Antibodies against thyroglobulin (TgAK) and thyroid peroxidase (TPO) or microsomal antibodies (MAK) were found in 19 patients (19%). The incidence of biochemical immunological thyroiditis was not significantly different from the control group. But thyroid volume was significantly higher in patients (21 versus 15.6 ml, p < 0.03). Goitre (> 18 ml) was diagnosed in 52% (n = 57) of the patients, although 43 had normal TRH-test results with delta TSH 2.5-12.5 microU/ml. So-called subclinical (latent) hypothyroidism (delta TSH > 12.5 microU/ml) was found in 29 patients; 18 of these infertile women had no goitre. Iodine avidity (99mTc-uptake) increased significantly with the increase in thyroid volume, but showed a tendency to lower values with increasing delta TSH-values and higher iodine avidity in women with thyroid enlargement (n = 109). During follow-up of 12-24 months 10 women with goitre conceived spontaneously after initiation of iodine and/or L-thyroxine 100 micrograms treatment. These data support recent studies, that factors other than TSH cause thyroid enlargement.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Disorders of thyroid function and sterility in the woman]. 843 26

The objective of this study was to: (1) assess the relative prevalence of ovarian, thyroid, nuclear, and cardiolipin antibodies associated with premature menopause and unexplained infertility and (2) compare ovarian and thyroid antibodies in premature menopause, unexplained infertility, and the general population. Autoantibodies were evaluated in women with premature menopause (n = 30), unexplained infertility with (n = 38) or without (n = 15) prior gonadotropin-induced ovulation, and normal cycling controls (n = 12) and in a population of women obtained from a blood bank (n = 53). Antibodies to ovary (OVAB), thyroid (THYAB; thyroid peroxidase and thyroglobulin), cardiolipin, and eight nuclear antigens were assessed by enzyme immunoassay. Organ-specific antibodies (ovary and thyroid) were present with significantly greater frequency than non-organ-specific antibodies (nuclear and cardiolipin) in premature menopause and unexplained infertility (60% (50/83) vs 16% (13/83) respectively; P < 0.0001). OVAB (53%, 44/83) were significantly more frequent than THYAB (30%, 25/83) in premature menopause and unexplained infertility (P = 0.0030). THYAB did not differ among all groups (P = 0.78). In premature menopause and treated or untreated unexplained infertility OVAB frequencies were 53, 61, and 33%, respectively, and were significantly more frequent than in the population (17%) (P = 0.0001). In unexplained infertility, individuals with no prior gonadotropin-induced ovulation had a lower frequency of OVAB than treated individuals (P = 0.07). The frequency distribution of optical density values for OVAB was significantly higher for premature menopause and unexplained infertility than for population or normal cycling women (P < 0.0001). Thus, only ovarian antibodies were significantly more frequent than other antibody markers of autoimmunity in premature menopause and unexplained infertility.
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PMID:Ovarian autoimmunity: greater frequency of autoantibodies in premature menopause and unexplained infertility than in the general population. 1007 66

This study was undertaken to evaluate whether the presence of thyroid antibodies in euthyroid women is associated with an adverse outcome in an in-vitro fertilization (IVF)-embryo transfer programme. In 24 women (study group: mean age +/- SD: 31.5 +/- 4.4 years) who failed to conceive after having three or more cycles of IVF and embryo transfer, serum concentrations of thyroglobulin (TG), thyroid peroxidase antibodies (TPO) and anticardiolipin antibodies (IgG and IgM) were measured using commercially available kits. The control group comprised 24 consecutive patients without endocrine dysfunction (mean age +/- SD: 30.3 +/- 4.1 years) seeking infertility treatment in our department of assisted reproduction. All patients in both the study and the control groups were determined to be euthyroid by demonstrating normal concentrations of thyroid-stimulating hormone (TSH). In the study and control groups respectively, 13 and two patients demonstrated positive titres of TG, TPO or both thyroid antibodies (Fisher's exact test: P = 0.002). Mean serum concentrations of TG were significantly increased in the study group compared to the control subjects (156 +/- 167 IU/ml versus 33.5 +/- 32.0 IU/ml; U-test: P = 0.009). Serum concentrations of TPO and anticardiolipin antibodies were similar in both groups. Our investigations revealed that thyroid antibodies might be independent markers for reproductive failure in an IVF-embryo transfer programme.
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PMID:Increased prevalence of thyroid antibodies in euthyroid women with a history of recurrent in-vitro fertilization failure. 1068 94

A prospective study was undertaken in 438 women (ages, 32 +/- 5 years) with various causes of infertility, and in 100 age-matched (33 +/- 5 years) healthy parous controls with the aim of assessing the prevalence of autoimmune thyroid disease (AITD) and hitherto undisclosed alterations of thyroid function. Female origin of the infertility was diagnosed in 45% of the couples, with specific causes including endometriosis (11%), tubal disease (30%), and ovarian dysfunction (59%). Male infertility represented 38% and idiopathic infertility 17% of the couples. Overall, median thyrotropin (TSH) was significantly higher in patients with infertility compared to controls: 1.3 (0.9) versus 1.1 (0.8) mIU/L. Serum TSH above normal (>4.2 mIU/L) or suppressed TSH (<0.27 mIU/L) levels were not more prevalent in the infertile women than in controls. The prevalence of positive thyroid peroxidase antibody (TPO-Ab) was higher in all investigated women of infertile couples, compared to controls (14% vs. 8%), but the difference was not significant. However, in infertility of female origin, a significant higher prevalence of positive TPO-Ab was present, compared to controls: 18% versus 8%. Furthermore, among the female causes, the highest prevalence of positive antibodies was observed in women with endometriosis (29%). When thyroid antibodies were positive, both hypothyroidism and hyperthyroidism were more frequent in all women of infertile couples and in the women with a female infertility cause, compared to women in the same groups but without positive TPO-Ab. The present study shows that in infertile women, thyroid autoimmunity features are significantly more frequent than in healthy fertile controls and this was especially the case for the endometriosis subgroup.
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PMID:Thyroid dysfunction and autoimmunity in infertile women. 1249 77

Infertility is defined as the inability to conceive after one year of regular intercourse without contraception. The prevalence of infertility is estimated between 12 and 14% and remains stable in recent years. It thus represents a common condition, with important medical, economic and psychological implications. According to a standard protocol infertility evaluation usually identifies different causes, including, male infertility (30%), female infertility (35%), the combination of both (20%), and finally unexplained or "idiopathic" infertility (15%). Female causes of infertility comprise endometriosis, tubal damage and ovulatory dysfunction (OD). Thyroid dysfunction is a condition known to reduce the likelihood of pregnancy and to adversely affect pregnancy outcome. Data on the relationship between thyroid disorders and infertility remain scarce and the association with a particular cause of infertility has not thoroughly been analyzed. In a case-control study we have shown that the relative risk of positive TPO-Abs in infertility due to a female cause and in particular related to endometriosis is significantly increased. Thyroid dysfunction itself is a condition interfering with normal ovarian function and was more frequent in women with positive anti-TPO Abs. We therefore propose that a systematic screening of TSH, free T4 and TPO-Ab could be considered in all women with a female cause of infertility. Prospective follow-up of a cohort of infertile women undergoing assisted reproduction shows a significant increased risk of miscarriage in women with positive anti-TPO Abs compared to women without thyroid auto-immunity after clinical pregnancy is established by the ART procedure. The frequent association of the presence of anti-TPO-Abs and miscarriage is hypothetical explained by the fact that organ specific autoimmune diseases may be secondary to some basic cellular abnormality that directly affects pregnancy outcome. Alternatively, women with thyroid autoimmunity, may experience greater changes in free thyroxine levels during ART and subsequent pregnancy interfering with genital tract physiology and fetal development. Determining the presence of thyroid antibodies before ART procedure is thus useful in identifying women at risk for subsequent clinical miscarriage.
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PMID:Thyroid and infertility. 1264 31

Thyroid hormones have profound effects on reproduction and pregnancy. There is a known association of hyper- and hypothyroidism with menstrual disturbances and decreased fecundity. Women with reproductive failure also have an increased prevalence of organ specific autoimmunity compared to fertile women. The present study aims to answer the following questions: 1) is there an increased prevalence of thyroid antibodies in infertile women? 2) are thyroid antibodies associated with a particular cause of infertility? and 3) do these antibodies influence outcome of the in vitro fertilization procedure? The answers to the two first questions were evaluated with a case-control study looking at the occurrence of thyroid autoimmunity and thyroid function tests among women of infertile couples (n=438), presenting for the first time at the department of reproductive medicine. For comparison, a control population of parous women (n=100), matched for age, was included. In 45% of the infertile couples a female cause of infertility was identified: endometriosis (11%), tubal disease (30%) and ovarian dysfunction (59%). Male infertility was diagnosed in 38% and idiopathic infertility in 17% of the couples. Mean serum TSH levels were significantly higher in patients with infertility compared with control patients: 1.6 +/- 2.6 versus 1.2 +/- 0.7 mIU/L. The proportion of positive TPO-Abs was higher in all women of infertile couples, compared with controls (14% versus 8%), but the difference was not significant. Considering only the female causes of infertility a significant higher proportion of women had positive TPO-Abs compared with controls (18% versus 8%), and in particular a high prevalence of thyroid autoimmunity was found in women suffering from endometriosis (29%). Both hypo- and hyperthyroidism were more frequent when TPO-Abs were positive, compared to women without thyroid autoimmunity. The results of the present study indicate that endometriosis, increases the relative risk for associated thyroid autoimmunity to 2.3, and therefore screening for thyroid auto-antibodies could be systematically proposed in these women.
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PMID:Thyroid disorders in infertile women. 1270 33

Subclinical hypothyroidism is associated with aspecific complaints such as tiredness, cognitive and depressive complaints, subtle disturbances in lipid values, an increased risk of cardiovascular disease, ovulatory dysfunction and a negative effect on foetal psychomotor development and pregnancy outcome. Subclinical hyperthyroidism is associated with atrial fibrillation, osteoporosis and dementia. Not enough prospective randomised studies with hard outcomes are available to provide evidence-based general recommendations. Therefore, the decision as to whether or not a patient should be treated needs to be made on an individual basis. For subclinical hypothyroidism it is advisable to consider treatment in the case of positive thyroid peroxidase antibody tests, a TSH concentration higher than 10 mU/l, the presence of one or more risk factors for cardiovascular disease, infertility on the basis of ovulatory dysfunction, and pregnancy. In the case of complaints of tiredness and certainly in the case of depression or cognitive dysfunction, a 3-month trial treatment can be considered. This leads to a decrease of the complaints in about 25% of cases. As negative effects are associated with the treatment, we advise an expectant approach in all other cases with a yearly monitoring of the TSH concentration. For subclinical hyperthyroidism it is advisable to consider treatment in the case of a nodular goitre, and especially in the case of atrial fibrillations. If subclinical hyperthyroidism persists in the absence of nodular thyroid disease, an expectant approach appears to be justified.
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PMID:[Subclinical functional disorders of the thyroid gland]. 1284 32

Pregnancy has an effect on thyroid economy with significant changes in iodine metabolism, serum thyroid binding proteins, and the development of maternal goiter especially in iodine-deficient areas. Pregnancy is also accompanied by immunologic changes, mainly characterized by a shift from a T helper-1 (Th1) lymphocyte to a Th2 lymphocyte state. Thyroid peroxidase antibodies are present in 10% of women at 14 weeks' gestation, and are associated with (i) an increased pregnancy failure (i.e. abortion), (ii) an increased incidence of gestational thyroid dysfunction, and (iii) a predisposition to postpartum thyroiditis. Thyroid function should be measured in women with severe hyperemesis gravidarum but not in every patient with nausea and vomiting during pregnancy. Graves hyperthyroidism during pregnancy is best managed with propylthiouracil administered throughout gestation. Thyroid-stimulating hormone-receptor antibody measurements at 36 weeks' gestation are predictive of transient neonatal hyperthyroidism, and should be checked even in previously treated patients receiving thyroxine. Postpartum exacerbation of hyperthyroidism is common, and should be evaluated in women with Graves disease not on treatment. Radioiodine therapy in pregnancy is absolutely contraindicated. Hypothyroidism (including subclinical hypothyroidism) occurs in about 2.5% of pregnancies, and may lead to obstetric and neonatal complications as well as being a cause of infertility. During the last few decades, evidence has been presented to underpin the critical importance of adequate fetal thyroid hormone levels in order to ensure normal central and peripheral nervous system maturation. In iodine-deficient and iodine-sufficient areas, low maternal circulating thyroxine levels have been associated with a significant decrement in child IQ and development. These data suggest the advisability of further evaluation for a screening program early in pregnancy to identify women with hypothyroxinemia, and the initiation of prompt treatment for its correction. Hypothyroidism in pregnancy is treated with a larger dose of thyroxine than in the nonpregnant state. Postpartum thyroid dysfunction (PPTD) occurs in 50% of women found to have thyroid peroxidase antibodies in early pregnancy. The hypothyroid phase of PPTD is symptomatic and requires thyroxine therapy. A high incidence (25-30%) of permanent hypothyroidism has been noted in these women. Women having transient PPTD with hypothyroidism should be monitored frequently, as there is a 50% chance of these patients developing hypothyroidism during the next 7 years.
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PMID:Thyroid disorders associated with pregnancy: etiology, diagnosis, and management. 1564 99

Congenital hypothyroidism is the most common neonatal metabolic disorder and results in severe neurodevelopmental impairment and infertility if untreated. Congenital hypothyroidism is usually sporadic but up to 2% of thyroid dysgenesis is familial, and congenital hypothyroidism caused by organification defects is often recessively inherited. The candidate genes associated with this genetically heterogeneous disorder form two main groups: those causing thyroid gland dysgenesis and those causing dyshormonogenesis. Genes associated with thyroid gland dysgenesis include the TSH receptor in non-syndromic congenital hypothyroidism, and Gsalpha and the thyroid transcription factors (TTF-1, TTF-2, and Pax-8), associated with different complex syndromes that include congenital hypothyroidism. Among those causing dyshormonogenesis, the thyroid peroxidase and thyroglobulin genes were initially described, and more recently PDS (Pendred syndrome), NIS (sodium iodide symporter), and THOX2 (thyroid oxidase 2) gene defects. There is also early evidence for a third group of congenital hypothyroid conditions associated with iodothyronine transporter defects associated with severe neurological sequelae. This review focuses on the genetic aspects of primary congenital hypothyroidism.
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PMID:Genetics of congenital hypothyroidism. 1586 66

Overt hypothyroidism is always an indication for substitution with levothyroxine. In patients with subclinical hypothyroidism and clearly elevated TPO antibodies, a wish to bear a child, infertility, and pregnancy, as also hypothyroidism-associated symptoms, including depression, a trial substitution with levothyroxine is justified. Before long-term treatment is initiated, an improvement in the clinical symptoms must be confirmed. Even though levothyroxine reduces the LDL cholesterol, or other risk factors are improved, it has not so far been unequivocally shown that levothyroxine reduces morbidity and mortality. These questions should be investigated in prospective clinical studies.
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PMID:[Subclinical hypothyroidism--what level of TSH is an indication for substitution?]. 1656 89


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