Causes
The vast majority of cases are thought to be due to spontaneous genetic mutations. It can be associated with mutations affecting the cohesin complex.As of 2018, it was confirmed that 500 genetic mutations have been associated with the condition; occurring on 7 different genes. In around 30% of cases of CdLS the genetic cause remains undiscovered. The wide variation in phenotype is attributed to a high degree of somatic mosaicism in CdLS as well as the different genes and type of mutations. For this reason people with CdLS can have very different appearance,  abilities,  and associated health issues. The latter two genes seem to correlate with a milder form of the syndrome.In 2004, researchers at the Childrens Hospital of Philadelphia (United States) and the University of Newcastle upon Tyne (England) identified a gene (NIPBL) on chromosome 5 that causes CdLS when it is mutated. Since then, additional genes have been found (SMC1A, SMC3 and HDAC8, RAD21) that cause CdLS when changed. In July 2012, the fourth "CdLS gene"—HDAC8—was announced. HDAC8 is an X-linked gene, meaning it is located on the X chromosome. Individuals with CdLS who have the gene change in HDAC8 make up just a small portion of all people with CdLS. Evidence of a linkage at chromosome 3q26.3 is mixed.Genetic alterations associated with CdLS have been identified in genes NIPBL, SMC1A and SMC3 as well as the more recently identified genes RAD21 and HDAC8. All of these genetic alterations occurring in CdLS patients affect proteins that function in the cohesin pathway.
SMC1A, SMC3 and RAD21 proteins are structural components of the cohesin ring complex. NIPBL is involved in the loading of the cohesin ring onto chromosomes, and HDAC8 deacylates SMC3 to facilitate its function. The cohesin pathway is involved in cohesion of sister chromatids during mitosis, DNA repair, chromosome segregation and the regulation of developmental gene expression. Defects in these functions are theorised to underlie some of the features of CdLS. In particular, defective DNA repair may underlie the features of premature aging. Diagnosis
The diagnosis of CdLS is primarily based on clinical findings by a clinical geneticist; and in some cases may be confirmed through laboratory testing. Treatment
Often, an interdisciplinary approach is recommended to treat the issues associated with CdLS. A team for promoting the childs well-being often includes speech, occupational and physical therapists, teachers, physicians, and parents.Cornelia de Lange syndrome (CdLS) affects many different systems of the body, medical management is often provided by a team of doctors and other healthcare professionals. Treatment for this condition varies based on the signs and symptoms present in each person.