RESUMEN
Achondroplasia and autism spectrum disorder (ASD) are two genetically based disorders. The coexistence of autism with chromosomal abnormalities such as Down syndrome, monogenic syndromes such as tuberous sclerosis, Fragile X, and Rett syndrome, and microdeletion syndromes such as Phelan-McDermid syndrome helps to shed light on the genetic basis of autism spectrum disorder. The association between ASD and achondroplasia has been reported twice in the literature. In this article, we report Turkish patients who were born as identical twins from IVF pregnancy of 34 and 36-year-old parents, clinically and molecularly diagnosed with achondroplasia, and diagnosed with ASD at the age of 39â months. Our case is the first twin patient with the coexistence of achondroplasia and autism. We discuss environmental and genetic factors contributing to the development of ASD.