Therefore, the diagnostic evaluation for autism should include a clinical genetic evaluation with collection of detailed family and medical histories, a genetic consultation to evaluate for clinical genetic syndromes (e.g., dysmorphic features, birth marks, and macrocephaly), cytogenetic problems (chromosomes, FISH), and DNA testing (fragile X, Rett and PTEN mutations), chromosomal microarray studies for structural genomic and mtDNA problems, and biochemical (organic, amino-, and fatty acid levels) and mitochondrial function (lactate/pyruvate) assays. The gene discussed is PTEN; the disease is autism.