Over the past several years, genetic testing has undergone many technological advances. One of the main changes in genetic analysis is the emergence of microarray technology. Microarray is also able to detect small deletions and duplications in DNA that were not previously detectable by looking at a person’s chromosomes under a microscope (what is known as a karyotype, or chromosomal analysis). Therefore, microarray has become the preferred test over standard karyotype analysis, particularly for individuals with developmental delay/intellectual disability, autism spectrum disorders, and multiple congenital anomalies. If your child was seen by our division prior to 2005 and had routine karyotype analysis that did not reveal a diagnosis, we encourage you to re-contact our office to discuss the utility of microarray testing.