Here, we report a patient who displayed prenatal onset growth delay and ACH and carried a small de novo duplication at 7p12.1 that involved the GRB10 gene in addition to a heterozygous point mutation at FGFR3. We detected the smallest known duplication in a patient who displayed one of the typical clinical features of SRS. The gene discussed is FGFR3; the disease is achondroplasia.