A population-based study on the frequency of additional congenital malformations in infants with congenital hypothyroidism: data from the Italian Registry for Congenital Hypothyroidism (1991-1998).

In the last decade a high frequency of other congenital anomalies has been reported in infants with congenital hypothyroidism (CH) detected by neonatal screening. In the present study the occurrence of additional congenital malformations (CM) in the population of CH infants detected in Italy between 1991 and 1998 (n = 1420) was investigated. In Italy all of the centers in charge of screening, treatment, and follow-up of CH adhere to the Italian National Registry of infants with CH. In this study a high prevalence of additional CM (8.4%), more than 4-fold higher than that reported in the Italian population (1-2%), was found in the population of CH infants. Cardiac anomalies represented the most frequent malformations associated with CH, with a prevalence of 5.5%. However, a significant association between CH and anomalies of nervous system, eyes, and multiple CM was also observed. In conclusion, the significantly higher frequency of extrathyroidal congenital malformations reported in the CH infants than in the general population represents a further argument supporting the role of a genetic component in the etiology of CH. Investigations of the molecular mechanisms underlying developmental events of formation of thyroid and other organs represent critical steps in the knowledge of CH etiology.

Postpartum thyroiditis is associated with fluctuations in transforming growth factor-beta1 serum levels.

Postpartum thyroiditis (PPT) is characterized by a rapid evolution and recovery of euthyroidism. Therefore, it can represent a good model to study early cytokine fluctuations in autoimmune thyroid diseases. TGFbeta1 is an immunosuppressive cytokine, as it inhibits T and B cell proliferation, natural killer cell cytotoxic activity, and the generation of T cell cytotoxicity. The aim of this study was to assess serum concentrations of TGFbeta1 during pregnancy and to study possible serum fluctuations of this cytokine during the different phases of PPT. Thyroid biochemical pattern, antithyroid autoantibodies (ATA), and total and active TGFbeta1 (aTGFbeta1) serum concentrations were evaluated in 63 pregnant women. Thirty-four of them were ATA(+), and 29 were ATA(-). Twenty of the 34 ATA(+) women were followed in the postpartum year. Nine of these 20 women developed PPT; 11 remained euthyroid. All of the PPT women became euthyroid during the follow-up. Our results showed 1) detectable serum levels of aTGFbeta1 in 50% of ATA(+) pregnant women, suggesting that the presence of autoantibodies may characterize a favorable condition for TGFbeta1 activation; and 2) decreased total TGFbeta1 and increased aTGFbeta1 serum levels during the active phase of PPT in ATA(+) women. This seems to suggest that inflammation may be responsible for TGFbeta1 activation and autoantibody increase because of antigen release. Although further studies of women with persistent hypothyroidism after the postpartum year are needed, the possibility that the enhanced activation of TGFbeta1 may contribute to resolution of thyroid inflammation postpartum cannot be excluded.

High frequency of antithyroid autoantibodies in pregnant women at increased risk of gestational diabetes mellitus.

BACKGROUND: Thyroid autoantibodies (ThyAb) and subclinical hypothyroidism occur more frequently in pregnant women with insulin-dependent diabetes mellitus than in healthy pregnant women. Few studies have investigated the presence of ThyAb in women with gestational diabetes mellitus (GDM), and no significant association between diabetes in pregnancy and thyroid function has been reported. OBJECTIVE: To assess the thyroid biochemical profile and estimate the prevalence of ThyAb in a group of pregnant women at increased risk of GDM due to family and personal risk factors, and to investigate the relationship between a positive family history of diabetes or thyroid diseases and the eventual presence of ThyAb during pregnancy. METHODS: Oral glucose tolerance, serum ThyAb and thyroid function were evaluated in 181 pregnant women with increased risk for GDM (study group). Seventeen healthy pregnant women without risk factors for GDM and with a normal glucose tolerance were recruited as controls. RESULTS: The women who developed GDM showed a mean free thyroxine concentration significantly lower than that observed in the healthy pregnant women and in those with impaired gestational glucose tolerance and normal glucose tolerance. Twenty-nine of the 181 women in the study group (16%) were ThyAb positive. However, the risk of being ThyAb positive during pregnancy was three times greater in the women with positive family history of both diabetes mellitus and thyroid disease than in those with no family history of these conditions. CONCLUSIONS: This study showed that women with increased risk of GDM, mostly those with family history of diabetes mellitus and thyroid disease, also have an increased risk of being ThyAb positive during pregnancy. It also highlighted the importance of evaluating thyroid function in pregnant women with impaired glucose tolerance, in view of their increased risk of subclinical hypothyroidism.

Effect of propylthiouracil-induced hypothyroidism on membranes of adult rat brain.

The effect of hypothyroidism on the lipid composition of myelin and synaptosomes isolated from adult rat brain was investigated. The animals were made hypothyroid by adding 0.05% propyl-2-thiouracil to their drinking water for four weeks. This pathological state resulted in a significant increase in the relative percentage of choline glycerophospholipids in synaptosomes with a concomitant decrease in ethanolamine glycerophospholipids as compared to controls. In myelin, hypothyroidism significantly influenced only the relative percentage of sulfatides. The effect of the hypothyroid state on mature brain was also reflected in changes in the membrane fatty acid composition. Myelin and synaptosomes showed an increase in arachidonic (20:4) and eicosatrienoic (20:3) acids and an increase in the fatty acid unsaturation index. Furthermore, the 20:4/20:3 and 20:3/18:2 ratios were lower and higher, respectively, in treated animals. The data indicate that hypothyroidism affects the lipid composition of synaptosomes and myelin even though the effects were less pronounced in myelin. The lipid changes observed in hypothyroidism may be of physiological significance, as it is well known that lipid composition modulates various membrane-bound enzymes, transporters and receptors.

Occurrence of anti-thyroid autoantibodies in children vertically infected with HIV-1.

Autoimmune phenomena, especially occurrence of non organ-specific autoantibodies, are common in congenitally acquired HIV infection, mostly in the symptomatic stages of the disease. Anti-thyroid autoantibodies detected in adult patients represent the only type of organ-specific autoantibodies reported in HIV infection. As far as we know, occurrence of these autoantibodies has not been observed in HIV infected children. In this study thyroid biochemical pattern and possible occurrence of anti-thyroid autoantibodies were investigated in 40 vertically HIV infected, 18 seroreverted and 22 healthy children. 34% of HIV infected symptomatic children showed anti-thyroglobulin antibodies. Asymptomatic patients, seroreverted and healthy controls did not show any anti-thyroid antibodies at the time of the study. High Tg levels were observed in 38% of the 40 HIV infected patients and high TSH concentrations were found in 27.5% of the HIV children. High TSH values were more frequently observed in the infected children with moderate or severe immunocompromised status. Thyroxine binding globulin levels were high in 68% of the HIV children and in 22% of the seroreverted. The finding of anti-thyroid autoantibodies in congenital HIV infected children confirms the thyroid's involvement in HIV infection and provides more information about the wide spectrum of autoimmune phenomena observed in the infection.

Health status and internal radiocontamination assessment in children exposed to the fallout of the Chernobyl accident.

The Chernobyl fallout caused release of radioisotope contaminants in a very large area that includes Belarus, the Ukraine, and the Russian Federation. In this study, the authors monitored the health status and level of internal contamination in 422 children who resided in the aforementioned areas and who were < or = 10 y of age at the time of the accident. The children came to Italy for a 1-mo period between 1991 and 1992. During this time, the children underwent pediatric checkups and biochemical, immunological, and thyroid analyses. All children underwent whole-body counter measurements, and urine radiotoxicological analysis was performed for 224 of them. The 24 children evacuated from Pripiat, a village very close to the Chernobyl reactor site, were selected for cytogenetic analysis. All of these children continue to have a detectable internal contamination of caesium radioisotopes. This condition is likely the result of ground and foodstuff contamination in the various areas. The children did not evidence overt pathologies related to ionizing radiation. However, minor alterations in immunological and thyroid parameters were observed in the group of the evacuated children. Traditional cytogenetic dosimetry was not possible, but the occurrence of acentric fragments was observed-indicating a persistent effect of continuous exposure to low doses of radiation.

[The association between hypothyroidism and other congenital defects. The experience of the National Registry in 1987-1992]. / Associazione tra ipotiroidismo e altri difetti congeniti. L'esperienza del Registro Nazionale negli anni 1987-1992.

This study considers the birth defects (BD) observed from 1987 to 1992 in 35/811 newborns with congenital hypothyroidism (CH) diagnosed by neonatal screening and included in the National Register. The BD incidence was higher than in the general population (4.3 vs 2.5-3%) and especially the one of the congenital heart diseases, (CHD) (2.1 vs 0.3-0.8%). Furthermore the CHD were more frequently observed in females than in males (M/F = 1/4.7). These results seem not to be casual but the reasons remain unknown. The most frequent CHD observed were the septal defects and the pulmonary stenosis. Further are presented and discussed the main findings of 2 groups of CH patients (with and without BD). These results are a good instance of the National Register applications, also for less known aspects of the CH like the concomitant BD.

[The evaluation of the risk factors for congenital hypothyroidism: the outlook of a case-control study]. / Valutazione dei fattori di rischio dell'ipotiroidismo congenito: prospettive di uno studio caso-controllo.

The availability of a National Register of congenital hypothyroid infants allowed to perform descriptive studies on characteristics of the cases and the efficiency of the neonatal screening. Continuous and exhaustive recording of data concerning congenital hypothyroidism cases provided valuable epidemiological informations about congenital hypothyroidism in Italy. Moreover, the National Register allowed to develop a network of collaboration which can promote a population based case-control study. As the etiopathogenesis of congenital hypothyroidism has not been completely elucidated, performing of a case-control study can contribute to evidence the most important risk factors of congenital hypothyroidism and to improve the prevention also by prenatal diagnosis of this disease. Screening centers will be involved in the study and questionnaires of the National Register for congenital hypothyroidism will be used to record case and control informations. A biological bank concerning cases, controls and their parents, will be organized.

[Re-evaluation of the diagnosis in congenital hypothyroidism]. / La rivalutazione della diagnosi nell'ipotiroidismo congenito.

Newborn screening for congenital hypothyroidism (CH) has become routine in Italy. It provided new information regarding the epidemiology, diagnosis and treatment of CH infants and allowed to identify transient disorders of thyroid function in infancy. In fact, when the permanence of hypothyroidism has not been established in the newborn period, a confirmation of the diagnosis at 2-3 years of life should be performed. In this study results regarding the diagnosis reevaluation performed in 23 out of 184 CH children followed at the follow-up center for CH of the University of Rome "La Sapienza", are reported. Eleven of 23 reevaluated children had transient hypothyroidism (TH) and permanent CH was confirmed in the others. Four of the 11 TH children had law gestational age at birth, 1 had high antithyroid peroxidase titre due to maternal autoimmune thyroiditis and 2 were resident in iodine deficient areas. Our results show the importance of diagnosis reevaluation to identify transient disorders of thyroid function in infancy and confirm the role of neonatal, maternal and environmental factors in the etiopathogenesis of TH.

[Effects of the combined deficiency of selenium and iodine on thyroid function]. / Effetti della deficienza combinata di selenio e iodio sulla funzionalità tiroidea.

Recent studies reported the role of several trace elements in health and disease. The role of iodine deficiency in thyroid dysfunction is well known. Also the selenium deficiency has been reported to be correlated to thyroid dysfunctions. In fact, although the major role of selenium is related to the glutathione peroxidase system, which protects cellular structures from oxidative damages, selenium plays also an important role in thyroid hormone metabolism as an essential component of the three deiodinase. These regulate inter-conversion of active and inactive forms of iodothyronines. Several studies have been carried out to establish the role of combined selenium and iodine deficiency. This review aims to provide information on the relationship between selenium and iodine intake and thyroid function. Furthermore, the state of art on the effects of the combined deficiency of selenium and iodine is also provided.

Endocrine response to HIV infection. Involvement of thyroid gland.

Endocrine dysfunctions were associated at different stages of infection, including those early in the course of HIV infection. In fact adrenal insufficiency, hyporeninemic hypoaldosteronism, hyponatremia, reduced gonadotropins levels, gonadal abnormalities and changes in hormone-binding proteins were reported in HIV infection. Also a thyroid involvement with autoimmune phenomena was observed in HIV infection by several studies giving different explanations of altered thyroid conditions. These findings suggest an effect of HIV on endocrine system. Recognition of endocrine manifestations in these patients may contribute to better characterize different stages of the infection and improve the management of HIV patients.

[Congenital hypothyroidism: organization and coordination of neonatal screening in Italy]. / Ipotiroidismo congenito: organizzazione e coordinamento dello screening neonatale in Italia.

Congenital hypothyroidism (IC) is the most frequent endocrine disease of the infancy and it is caused by primary deficiency of thyroid hormones. The damages derived by protracted hormone deficiency are diffused to all organs and systems and particularly severe for the development of central nervous system. Mental retardation can be prevented by early diagnosis and therapy. Early diagnosis is assured by neonatal thyroid screening performed on all newborns in the first days of life. The progress report on the screening situation in Italy as well as the national coordination realized in this field are presented.

[Neonatal screening in congenital hypothyroidism in Italy. The National Registry]. / Lo screening neonatale dell'ipotiroidismo congenito in Italia. Il Registro Nazionale.

Neonatal screening for congenital hypothyroidism (CH) began in Italy in 1977 and then progressively developed covering 97% of live births in 1992. The National Register of infants with congenital hypothyroidism was established in 1987 as a project of the Health Ministry and is coordinated by the Italian Institute of Health. The aim of the Register is to provide disease surveillance, to monitor the efficiency and effectiveness of neonatal screening and to allow the identification of possible etiological risk factors in congenital hypothyroidism. The results of the Register provided valuable epidemiological informations about congenital hypothyroidism in Italy and evidenced several areas in whom an increased incidence probably caused by iodine deficiency was observed. Discussion of Register data during annual national meetings has allowed an improvement of the screening program with particular regard to the beginning of therapy with L-thyroxine and its dose. Because of the wide spectrum of collected information, the National Register represents a useful tool for developing of collaborative studies concerning some aspects of CH not yet completely elucidated.

Thyroid autoimmunity in pregnant women at risk for GDM.

Presence of antithyroid autoantibodies (ThyAb) during pregnancy is strictly related to the risk of developing post partum thyroiditis (PPT) and this risk is increased in IDDM pregnant women. Gestational diabetes mellitus (GDM) is defined as carbohydrate intolerance of variable severity that begins, or is first diagnosed, during pregnancy. GDM is considered a risk factor for both type 1 and type 2 diabetes and various non-organ specific autoantibodies have been found to be associated with GDM, although there is little information on the association of GDM with thyroid autoimmunity. In this study oral glucose tolerance and prevalence of ThyAb were evaluated in a group of 41 pregnant women at increased risk of developing GDM and in a healthy control group. Our results showed that 22% of GDM risk group had impaired glucose gestational tolerance (IGGT) or GDM at the time of oral glucose tolerance test (OGTT). Moreover, ThyAb prevalence found in the women at increased risk of GDM (14.6%) was similar to that observed in healthy pregnant controls (12.5%). Nevertheless ThyAb frequency was higher in those GDM risk women with family history of diabetes (30.7%).

[Transient congenital hypothyroidism in iodine deficiency areas. Gruppo di Studio per il Registro Nazionale degli Ipotiroidei Congeniti]. / Ipotiroidismo congenito transitorio in aree iodocarenti. Gruppo di Studio per il Registro Nazionale degli Ipotiroidei Congeniti.

On the basis of data collected in the National Register of infants with congenital hypothyroidism (CH), a mean incidence of 1 case of CH to 3200 live births has been estimated in Italy. Nevertheless a higher incidence (> 1:2000) than national mean value has been observed in several districts of our country. The aim of this study was to verify a possible occurrence of transient hypothyroidism (TH) in these areas. Results of our study showed that the proportion of infants with thyroid in situ was significantly higher in the areas with very high CH incidence than in the remaining parts of the country. Also serum TSH levels at confirmation showed a less severe hypothyroidism in infants of these areas when compared with the other CH infants. Furthermore, preliminary results of diagnosis reevaluation showed 58% of TH in the areas with CH incidence > 1:2000. Lower percentages of TH have been observed in the other areas in relation to the decreasing of CH incidence. Most of the high CH incidence areas are historically affected by iodine deficiency. This observation supports the hypothesis that iodine deficiency can contribute to the occurrence of transient disorders of thyroid function in our population and stresses the need of promoting diffusion of an adequate iodine prophylaxis.

[Congenital forms of hypothyroidism: study of risk factors and preventive interventions]. / Forme congenite di ipotiroidismo: studio dei fattori di rischio e interventi di prevenzione. Gruppo di Studio per il Registro Nazionale degli Ipotiroidei Congeniti.

Maternal and child health represents one of the most relevant fields of interest in public health and particular attention is given to congenital pathologies. In Italy, the incidence of congenital hypothyroidism (CH) is 1:3200 live birth. CH is diagnosed at birth by neonatal thyroid screening. This allows a precocious onset of substitutive therapy which avoids severe psychomotor deficits in infants with CH. Moreover, the newborn screening program have permitted to identify transient disorders of thyroid function in newborns. These are essentially due to neonatal, maternal and environmental risk factors, especially iodine deficiency. The National Register (NR) of infants with CH was established in 1987. The aim of the NR is to provide disease surveillance and to monitor efficiency and effectiveness of neonatal screening. Furthermore, the NR represents an useful tool for developing epidemiological studies to identify possible environmental and/or familial risk factors of CH.

[Goiter prevalence and urinary excretion of iodine in a sample of school age children in the city of Rome]. / Prevalenza di gozzo ed escrezione urinaria di iodio in un campione di bambini in età scolare della città di Roma.

The aim of the study was the assessment of the urinary iodine excretion and the evaluation of thyroid volume compared with clinical examination in 1040 schoolchildren (6-14 years old), living in Rome. Mean urinary iodine excretion was 98.52 +/- 49.81 micrograms/l (median 92 micrograms/l). Thyroid enlargement, as assessed by palpation, was found to be grade 1A in 35.4% of the children, grade 1B in 9.6% and grade 2 in 0.2%. Thyroid volume, determined by ultrasound, increased with age, was significantly correlated with body surface area and was significantly higher in females, as compared to males, in the 11 and 12 years old group. Eleven children (1.9%) were negative at palpation (grade 0) but showed thyroid enlargement by ultrasound. The prevalence of goiter determined by ultrasound resulted to be 4.7%.

[Hypothyroxinemia in the low birth-weight infant in the screening of congenital hypothyroidism]. / L'ipotiroxinemia del neonato di basso peso nello screening dell'ipotiroidismo congenito.

Inside a pilot screening program for Congenital Hypothyroidism, T4 and TSH have been tested in sick and healty preteam and fullterm low birth weight (LBW) newborns during the first two months of life, 36 newborns affected by respiratory distress syndrome and 15 by sepsis have been included in the study. Blood samples were collected by heel puncture on 3rd, 10th, 20th, 40th and, in some cases, up to 60th day of life, and adsorbed on filter paper. Our findings show that hypothyroxinaemia in LBW newborns is strictly related to gestational age. In fact, among preterm infants with GA less than or equal to 33 weeks, 25 subjects (69,44%) showed T4 levels less than or equal to 6 micrograms/dl and 5 infants (13,88%) had T4 concentrations less than or equal to 2 micrograms/dl. The incidence of subjects with T4 values less than or equal to 6 micrograms/dl falls to 42,18% in the group of infants with GA = 34-36 weeks and to 17,27% in the group of fullterm LBW infants. None of these newborns showed thyroxine levels less than or equal to 2 micrograms/dl. All the examined infants showed normal TSH levels. The low T4 values may appear soon after birth or later (3rd-20th day of life) and sometimes persist up to 40th or 60th day, despite of always normal TSH levels. The mean of low T4 values at each sampling time is strictly and directly related to gestational age. (ABSTRACT TRUNCATED AT 250 WORDS)