Minor physical anomalies in autism: a meta-analysis

Autism is a complex neurodevelopmental disorder in which the interactions of genetic, epigenetic and environmental influences play a causal role. Despite the compelling evidence for a strong heritability, the etiology and molecular mechanisms underlying autism remain unclear. High phenotypic variability and genetic heterogeneity confounds the identification of susceptibility genes. The lack of robust indicators to tackle this complexity in autism has led researchers to seek for novel diagnostic tools to create homogenous subgroups. Several studies have indicated that patients with autism have higher rates of minor physical anomalies (MPAs) and that MPAs may serve as a diagnostic tool; however, the results have been inconsistent. Using the cumulative data from seven studies on MPAs in autism, this meta-analysis seeks to examine whether the aggregate data provide evidence of a large mean effect size and statistical significance for MPAs in autism. It covers the studies using multiple research methods till June 2007. The current results from seven studies suggested a significant association of MPAs in autism with a robust pooled effect size (d=0.84), and thereby provide the strongest evidence to date about the close association between MPAs and autism. Our results emphasize the importance of MPAs in the identification of heterogeneity in autism and suggest that the success of future autism genetics research will be exploited by the use of MPAs. Implications for the design of future studies on MPAs in autism are discussed and suggestions for further investigation of these important markers are proposed. Clarifying this relation might improve understanding of risk factors and molecular mechanisms in autism.

[Possible teratogenic effects of thiamazole]

A newborn male presented with choanal atresia and minor dysmorphic facial features. At 4 years of age he showed delayed speech and language development. His mother had been treated with thiamazole for pre-existing hyperthyroidism during the first 3 months of pregnancy. It is possible that the maternal use of thiamazole caused the congenital anomalies. Embryopathy caused by maternal thiamazole use during pregnancy has been described several times before and is mainly characterised by choanal atresia, oesophageal atresia, minor dysmorphic facial features, growth retardation and delayed psychomotor development. Because the use of propylthiouracil during pregnancy has not been associated with similar effects, it is the treatment of choice for hyperthyroidism during pregnancy. For pregnant women or women who wish to become pregnant, thiamazole should be prescribed only ifpropylthiouracil cannot be used.