Clinical Severity Score as a Prognostic Indicator of Communicative Functioning in Cornelia de Lange Syndrome.

Cornelia de Lange syndrome (CdLS) is a rare disorder associated with developmental delay, intellectual disability, autism features, and behavior regulation difficulties. CdLS has been considered to be a spectrum disorder that ranges from classical to atypical involvement. The severity of CdLS based on physical features has been associated with greater neurological abnormalities and hearing impairment; however, the relationship between CdLS severity and behavioral phenotype has not been examined. This study utilized data collected through the Coordination of Rare Diseases (CoRDS) registry. A total of 24 caregivers of an affected individual with CdLS (Mean age = 10.91, SD = 7.54, age 3 to 38 years) completed the assortment of inventories assessing medical history, developmental history, and behavior functioning to allow computation of a CdLS severity score based on an adapted form of a published CdLS Severity Scoring System. In our sample, approximately 50% of participants had severe involvement of CdLS, 29% moderate severity, and 21% with mild involvement. The severity of CdLS was associated with a greater deficit in verbal communication (r = 0.82, p < 0.001) and nonverbal communication (r = 0.63, p = 0.001), but not with a history of attention problems, self-injurious behaviors, behavior regulation, or restrictive and repetitive behaviors, despite controlling for age. Interestingly, when these relationships were explored in small subgroups of those with NIPBL (N = 6) and SMC1A variants (N = 5), this pattern was mainly observed among those with variants in NIPBL. Preliminary findings suggest that the severity of the clinical spectrum of CdLS based on physical features may be more intimately linked to select cognitive domains such as communicative functioning, as related to specific CdLS genotypes.