Testing is now available for Cornelia de Lange syndrome (CdLS), a condition that affects about 1 in 10,000 individuals, at The University of Chicago Genetics Services Laboratories. Previously, testing for CdLS relied on observation of physical features. Development of this test allows for improved genetic counseling and provides information to help families plan future pregnancies. The CETT Program was integral to the collaboration between the leading researcher for the condition, Ian Krantz, M.D., of The Children’s Hospital of Philadelphia, whose group found the gene; Julia Mairano, M.S., of the CdLS Foundation, Inc., and The University of Chicago Genetics Services Laboratories, a respected rare disease testing laboratory. Cornelia de Lange Syndrome is a genetic mutation that may result in low birthweight, slow growth, small stature, small head size, excessive body hair, gastroesophageal reflux, seizures, heart defects, cleft palate, bowel abnormalities, feeding difficulties, and developmental delay, among other symptoms. Not everyone with this condition has all of these symptoms or is affected in the same degree of severity. CdLS is caused by a mutation on the NIPBL (Nipped-B-like) gene on Chromosome 5. Because it is such a large gene, testing must be done on the affected person to determine the mutation before testing other family members or conducting prenatal testing.