Question: What are the genetic changes related to Cornelia de Lange syndrome ?
Answer: Cornelia de Lange syndrome can result from mutations in at least five genes: NIPBL, SMC1A, HDAC8, RAD21, and SMC3. Mutations in the NIPBL gene have been identified in more than half of all people with this condition; mutations in the other genes are much less common. The proteins produced from all five genes contribute to the structure or function of the cohesin complex, a group of proteins with an important role in directing development before birth. Within cells, the cohesin complex helps regulate the structure and organization of chromosomes, stabilize cells' genetic information, and repair damaged DNA. The cohesin complex also regulates the activity of certain genes that guide the development of limbs, face, and other parts of the body. Mutations in the NIPBL, SMC1A, HDAC8, RAD21, and SMC3 genes cause Cornelia de Lange syndrome by impairing the function of the cohesin complex, which disrupts gene regulation during critical stages of early development. The features of Cornelia de Lange syndrome vary widely, and the severity of the disorder can differ even in individuals with the same gene mutation. Researchers suspect that additional genetic or environmental factors may be important for determining the specific signs and symptoms in each individual. In general, SMC1A, RAD21, and SMC3 gene mutations cause milder signs and symptoms than NIPBL gene mutations. Mutations in the HDAC8 gene cause a somewhat different set of features, including delayed closure of the "soft spot" on the head (the anterior fontanelle) in infancy, widely spaced eyes, and dental abnormalities. Like affected individuals with NIPBL gene mutations, those with HDAC8 gene mutations may have significant intellectual disability. In about 30 percent of cases, the cause of Cornelia de Lange syndrome is unknown. Researchers are looking for additional changes in the five known genes, as well as mutations in other genes, that may cause this condition.
Source: GHR