Making the Diagnosis

Making the Diagnosis

So far, no specific criteria have been outlined to make the diagnosis of SATB2-associated syndrome (SAS). However, the diagnosis of SAS should be considered in anybody that has developmental delay with severely compromised or absent speech and that also has palatal and dental abnormalities (See Main Characteristics).

Regardless of the medical history and findings on physical exam, any of the potential mechanisms that result in the alteration of the SATB2 gene needs to be documented through genetic testing to make the diagnosis of SAS (See What Causes the Syndrome). The testing that could show changes in the SATB2 gene include:

  • Chromosomal microarray (CGH): also known as array CGH or SNP array, this test is designed to look for deletions (missing pieces) or duplications (extra pieces) throughout all the chromosomes. This test is available at many laboratories in the United States and around the world and is considered to be a first-line test in the evaluation of developmental delay and/or birth defects. The majority of deletions or duplications in chromosome 2 that include the SATB2 gene should be able to be detected by this test.
  • Sequencing of SATB2: sequencing of a gene refers to looking at all the individual letters in the gene for misspellings. Sequencing of only the SATB2 gene is available at a few laboratories in the world (3 according to the Genetic Testing Registry). This test, however, is unlikely to be commonly ordered since it tends to be more cost-effective to look at several genes at once rather than just this one.
  • Next Generation Sequencing testing: in this test, all the individual letters in several genes (ranging from a handful to several hundred) are looked at simultaneously. Because developmental delay and severe speech delay are main features of the SAS, testing for misspellings of the SATB2 gene is often conducted by this type of test when no other more distinctive medical issues are present. The SATB2 gene is included in panels that are offered by several laboratories targeting Autism, Developmental delay, or Intellectual disability (Ambry Genetics, Fulgent, Arkansas Children’s Hospital, many others). Dr. Zarate and Arkansas Children’s Hospital are developing testing for SATB2, along with many other genes, using this technology but targeting cleft palate and other abnormalities of the development of the cranium and the face.
  • Clinical Exome/Whole Exome Sequencing: In this test, the coding regions of several thousands (4000-5000) or all our 20,000 genes are looked at simultaneously. This test is also quickly becoming widely available worldwide.