S. Carta

Influence of environmental iodine deficiency on neonatal thyroid screening results

During a multicentric pilot screening program for congenital hypothyroidism a comparison between the results obtained from Urbino, an area characterized by low iodine supply and endemic goiter, and Rome, a non-endemic area, has been made. The evaluation of neonatal urinary iodine excretion in the two areas showed significantly lower iodine urinary excretion levels in Urbino than in Rome. A shift of TSH at screening toward higher values as well as a higher percentage of recall in Urbino area than in Rome was observed. This finding, which well correlates with a low environmental iodine supply, emphasizes the importance of screening for congenital hypothyroidism as a suitable index of the presence and action of goitrogenic factors in the environment.

The National Register of infants with congenital hypothyroidism detected by neonatal screening in Italy.

Neonatal screening for congenital hypothyroidism began in Italy in 1977 and then progressively developed covering 94% of live births in 1991. The National Register of infants with congenital hypothyroidism was established in 1987 as a project of the Health Ministry. The results of the Register provided valuable epidemiological information about congenital hypothyroidism in Italy and evidenced some aspects in the screening organization which had to be improved. Discussion of Register data during annual national meetings has recently allowed an improvement of the screening program with particular regard to the beginning of therapy with L-thyroxine and its dose.

Pilot study for congenital hypothyroidism, preliminary report

Preliminary results of a pilot study on congenital hypothyroidism performed on 8,025 newborns in Italy over a 10-month period are reported. The determination of both T4 and TSH on dried blood, spotted on filter paper, as screening procedure at day 3–5 of life revealed three cases of primary hypothyroidism and one case of hypo-thyroxin-binding-globulinemia (hypo-TBG-emia). The diagnosis of primary hypothyroidism was established on the basis of low T4and high TSH levels in two of the three cases; in the third, with elevated TSH and normal T4 levels at screening, thyroid scintiscan showed an ectopic gland located at the base of the tongue. In the case of hypo-TBG-emia, low T4and TBG levels were associated with normal TSH values. Some cases of transient hypothyroidism were observed in premature infants.

Familial thyroxine-binding globulin deficiency detected in a pilot screening program for congenital hypothyroidism

During a pilot screening program for congenital hypothyroidism, performed in Italy over a three years period on 38,000 newborns, seven cases (1/5,400) of thyroxine-binding globulin (TBG) deficiency, have been detected. None of these infants was affected by any pathology or had been treated with drugs which could explain TBG deficiency as an acquired condition. Familial studies pointed out that the transmission of the defect is consistent or compatible with X-chromosome linkage.

The sardinian autoimmunity study. 4. Thyroid and islet cell autoantibodies in sardinian pregnant women at delivery: a cross-sectional study.

A high incidence of autoimmune Type 1 diabetes mellitus (DM) has been clearly established in Sardinia. Although systematic epidemiological studies are still not available, an increased prevalence of thyroid autoantibodies (ATA) has been documented in the Sardinian adult population as compared to other Italian regions, suggesting that thyroid autoimmune disease may also have increased. We carried out a preliminary study with the aim of determining the prevalence of serological markers of thyroid (anti-thyroperoxydase antibodies, TPOAb) and islet cell (ICA) autoimmunity in a large number (no.=2249) of sera obtained from cord-blood of Sardinian pregnant women at delivery. The prevalence of TPOAb was 11.9%, while ICA were detected in 59 cases (2.6%). A higher prevalence of TPOAb (6/17=35.3%) was found in sera with high ICA titers (≥20 JDF-U), as compared to sera with low ICA titers (5-19 JDF-U) and to ICAnegative sera (3/42=7,1%; χ2=5.4, p=0.02 and 258/2190=11,8%; χ2=6.8, p=0.009 respectively). Fourteen women (all ICA-negative) were diabetic: 4 had Type 1 and 10 had gestational DM; due to the low number, no correlation could be established between DM type and TPOAb prevalence and/or titer. These preliminary data indicate that ATA are frequently observed in the general population of Sardinian pregnant women at term. As a consequence, even the frequency of postpartum thyroiditis is expected to be high. Although ATA were not increased in women with clinical overt diabetes, a higher prevalence of ATA was found in women with high titers of circulating ICA. Our results also confirm that Sardinia represents, perhaps for its peculiar genetic characteristics, an ideal place to study organ-specific autoimmunity.