Polymorphisms in the endothelial nitric oxide synthase gene in thalidomide embryopathy.

Thalidomide is one of the most potent teratogens known to humans. It is currently used for many clinical situations such as treatment of leprosy reactions and multiple myeloma. However, the teratogenic mechanisms by which it produces morphological defects still remain unclear. One of the hypotheses is the blockage of angiogenesis by reduction of nitric oxide (NO). In this study, we evaluated two functional polymorphisms of the endothelial nitric oxide synthase (eNOS) gene which is a constitutively expressed enzyme responsible for production of NO. The promoter -786T>C exon 7 (896G>T) polymorphisms were genotyped using real-time PCR for 28 individuals with thalidomide embryopathy (TE), 27 first-degree relatives of these individuals, and 68 individuals from the general population. Their allele, genotypic, and haplotypic frequencies were compared. A significant difference was observed in the -786T>C polymorphism genotypes (p=0.03) between the groups affected by TE and those unaffected (non-relatives). The TT genotype of the 896G>T polymorphism was observed in 10.7% of those affected and 2.9% of those unaffected, but the difference was not statistically significant (p=0.09). The haplotypic analysis indicated that the wild haplotype -786T/896G was distributed differently in the affected and unaffected groups (p=0.004). These results indicate that the individuals with TE have a higher frequency of alleles associated with lower expression of eNOS, indicating that this may be a genotype susceptible to TE.

Recognition of the phenotype of thalidomide embryopathy in countries endemic for leprosy: new cases and review of the main dysmorphological findings.

Thalidomide is the best-known teratogen worldwide. It was first marketed as a sedative in the late 1950s, but the birth of ~10 000 children with birth defects resulted in the withdrawal of thalidomide from the market in 1962. Thalidomide embryopathy affects almost all organs but the main defects are concentrated in the limbs, eyes, ears, and heart. Shortly after the withdrawal of thalidomide from the market, its effectiveness in the treatment of erythema nodosum leprosum, an inflammatory condition resulting from leprosy, was reported and since the mid-1990s, the drug has been used widely in the treatment of cancers and autoimmune diseases, among other conditions. 40 000 new cases of leprosy are diagnosed every year in Brazil. Although there is a strict legislation for the prescription and use of thalidomide in Brazil, cases of thalidomide embryopathy have continued to be reported. Here, we present two new cases of thalidomide embryopathy identified in 2011 and review the major clinical findings in the literature that can aid the identification of the embryopathy.

New cases of thalidomide embryopathy in Brazil.

Thalidomide is the best known human teratogen. Although withdrawn from the market in 1961, thalidomide was remarketed after 1965 in several countries, for the treatment of erythema nodosum leprosum. Thalidomide has a potent immunomodulatory property and has now a number of approved and off-label uses in dermatologic, oncologic, infectious and gastrointestinal conditions. In the U.S., FDA approved the use of thalidomide in 1998, but no cases of thalidomide embriophaty were registered after that. Since 1996 no new cases were reported in Latin America. However, the Teratogen Information Service (TIS) Porto Alegre, recorded three new cases of thalidomide embriophaty born in Brazil since 2005. Considering that these three cases were not registered through a systematic surveillance system, but that came to our attention through a series of coincidental random events, it can be assumed that the actual occurrence of affected babies by thalidomide continues being as frequent as denounced ten years ago.