Autoimmune thyroid disease (AITD), including Graves' disease (GD) and Hashimoto's thyroiditis (HT), is caused by multiple genetic and environmental factors. The clinical and immunological features of GD and HT are distinct; however, there are multiplex families with both GD and HT, and cases in which GD evolves into HT. Thus, there may be specific susceptibility loci for GD or HT, and common loci controlling the susceptibility to both GD and HT may exist. A genome-wide analysis of data on 123 Japanese sib-pairs affected with AITD was made in which GD- or HT-affected sib-pairs (ASPs) were studied to detect GD- or HT-specific susceptibility loci, and all AITD-ASPs were used to detect AITD-common susceptibility loci. Our study revealed 19 regions on 14 chromosomes (1, 2, 3, 5, 6, 8, 9, 10, 11, 12, 13, 15, 18 and 22) where the multipoint maximum LOD score (MLS) was >1. Especially, chromosome 5q31-q33 yielded suggestive evidence for linkage to AITD as a whole, with an MLS of 3.14 at D5S436, and chromosome 8q23-q24 yielded suggestive evidence for linkage to HT, with an MLS of 3.77 at D8S272. These observations suggest the presence of an AITD susceptibility locus at 5q31-q33 and a HT susceptibility locus at 8q23-q24.

A high prevalence of the activating BRAF mutation, BRAF(T1796A), is observed in adult papillary thyroid carcinomas (PTCs). The prognosis of childhood PTCs is generally fairly good despite the fact that distant metastases are often documented in these cases. To investigate the differences between the characteristics of childhood and adult PTCs, we analyzed both BRAF(T1796A) and RAS mutations in 31 Japanese and 48 post-Chernobyl Ukrainian thyroid carcinomas. In the 31 Japanese childhood cases, BRAF(T1796A) was found in only one instance (3.2%), and no RAS mutations were detected. In the Ukrainian subjects, of the 15 childhood and the 33 adolescent and young adult PTCs examined, the BRAF(T1796A) mutation was found in zero and eight cases, respectively, and RAS mutations were found in two of the young adult cases. In addition, 17 of the 48 Ukrainian cases showed expression of the RET tyrosine kinase region, indicating the existence of RET/PTC rearrangements. Unlike adult PTCs, we could detect no positive association between BRAF(T1796A) mutations and clinical parameters in the childhood carcinomas, suggesting that a low prevalence of BRAF(T1796A) is a common feature of PTCs in children regardless of radiation exposure levels. The differences in the prevalence of BRAF(T1796A) mutations between childhood and adult cases of PTC may well reflect inherent differences in the clinical features of these cancers between the two age groups.

Autoimmune thyroid disease (AITD) is caused by an immune response to self-thyroid antigens and has a significant genetic component. Antisense RNA transcripts have been implicated in gene regulation. Here we have identified a novel zinc-finger gene, designated ZFAT (zinc-finger gene in AITD susceptibility region), as one of the susceptibility genes in 8q23-q24 through an initial association analysis using the probands in the previous linkage analysis and a subsequent association analysis of the samples from a total of 515 affected individuals and 526 controls. The T allele of the single-nucleotide polymorphism (SNP), Ex9b-SNP10 located in the intron 9 of ZFAT, is associated with increased risk for AITD (dominant model: odds ratio = 1.7, P = 0.000091). The Ex9b-SNP10 falls into the 3'-UTR of truncated-ZFAT (TR-ZFAT) and the promoter region of the small antisense transcript of ZFAT (SAS-ZFAT). In peripheral blood lymphocytes, SAS-ZFAT is exclusively expressed in CD19+ B cells and expression levels of SAS-ZFAT and TR-ZFAT seemed to correlate with the Ex9b-SNP10-T-associated ZFAT-allele, inversely and positively, respectively. The Ex9b-SNP10 is critically involved in the regulation of SAS-ZFAT expression in vitro and this expression results in a decreased expression of TR-ZFAT. These results suggested that the SNP-associated ZFAT-allele plays a critical role in B cell function by affecting the expression level of TR-ZFAT through regulating SAS-ZFAT expression and that this novel regulatory mechanism of SNPs might be involved in controlling susceptibility or resistance to human disease.

The mechanisms of TSH-induced growth stimulation of thyrocytes in vivo have yet to be elucidated. We examined the antiapoptotic effect of TSH toward Fas antigen-mediated apoptosis of thyrocytes. Fas antigen was expressed on approximately 40% of unstimulated thyrocytes, and the expression was significantly inhibited by the addition of TSH in a dose-dependent manner. Treatment of thyrocytes with 8-bromo-cAMP mimicked the effect of TSH, suggesting that the inhibitory effect of TSH on Fas antigen expression was mediated by activating protein kinase A. In contrast, treatment of thyrocytes with either interleukin-1 beta (IL-1 beta) or interferon- gamma (IFN gamma) markedly increased Fas antigen expression on thyrocytes, and these effects were inhibited in the presence of TSH. The expression of the protooncogene product Bcl-2 did not change after the addition of TSH, 8-bromo-cAMP, IL-1 beta, IFN gamma, or a combination of TSH and IL-1 beta or IFN gamma. When thyrocytes stimulated with either IL-1 beta or IFN gamma were treated with anti-Fas IgM mAb, the cells were committed to apoptosis, whereas this apoptotic process was significantly inhibited by the addition of TSH. These results indicate that the Fas antigen is functionally expressed on the surface of thyrocytes, and TSH inhibits Fas antigen-mediated apoptosis of thyrocytes through the inhibitory effect of Fas antigen expression, resulting in the promotion of growth of the thyroid gland.

We compared fetal and maternal serum indexes of thyroid status at delivery in 70 patients with Graves' disease who required therapy with thionamides (such as propylthiouracil) during pregnancy. Forty-three mothers required thionamides until delivery (Group 1), whereas the drugs were discontinued during pregnancy after remission in 27 mothers (Group 2). Maternal free thyroxine levels were closely correlated with cord levels in both groups, being essentially identical in Group 2 but slightly lower in fetuses than in mothers in Group 1. Normal maternal free thyroxine levels did not preclude fetal hypothyroidism. The mothers and fetuses in Group 1 had a significantly higher incidence of antibodies that inhibit thyrotropin binding than did those of Group 2. However, a significant correlation between maternal levels of these antibodies and cord levels of free thyroxine or triiodothyronine was found only in Group 2, in which some maternal and cord thyroxine levels were in the thyrotoxic range at delivery, presumably because therapy was discontinued. These findings indicate that high free thyroxine levels and the presence of antibodies that inhibit binding of thyrotropin are useful indexes of the fetal need for antithyroid treatment, and that the thionamide dosage that maintains maternal free thyroxine levels in a mildly thyrotoxic range seems appropriate for maintaining euthyroid status in the fetus.

PTU therapy may be related to the appearance of MPO-ANCA, but MPO-ANCA does not appear to be closely related to vasculitis.

Subacute thyroiditis may trigger autoreactive B cells to produce TSH receptor antibodies, resulting in TSH receptor antibody-associated thyroid dysfunction in some patients.

The length polymorphism in the waxy gene, which encodes a granule-bound ADP-glucose-glucosyl transferase [granule-bound starch synthase I (GBSS I), E.C. 2.4.1.11] in barley ( Hordeum vulgare), was found. The 5' leader sequence of the waxy gene of barley germplasm from Japan and Korea was analyzed by the polymerase chain reaction (PCR). The waxy gene of these genetic stocks had three types of length polymorphisms, suggesting that there are insertion/deletion mutations at the 5' leader sequence of the waxy gene. DNA sequence analysis of the polymorphic PCR products showed that: (1) a 403-bp deletion mutation, which included a complete exon I, was found in the wax allele and a 193-bp insertion sequence was located in the intron I, and (2) the insertion sequence was also located in intron I of the Wax allele. The identity of the insertion sequence was completely conserved between the wax allele and the novel Wax allele. These finding s implying that the wax allele, which was found in indigenous waxy barley, originated in non-waxy barley with the novel Wax allele.