Facial expression of affect in children with Cornelia de Lange syndrome.

Matson et al. (2008) watched the faces of children with Cornelia de Lange syndrome during play. They compared each child’s positive and negative facial expressions to kids with other intellectual disabilities.

The team used slow-motion video coding. They counted how long each smile, frown, or neutral look lasted.

Kids with CdLS showed far fewer happy faces for every sad or angry face. The total time they spent smiling or frowning was the same as other kids, but the balance was off.

A flat or negative face was the norm, not a sign of boredom.

Guy et al. (2014) followed the same syndrome for two more years and saw the same gloomy ratio. Their longer view shows the low-positive pattern is stable, not a passing phase.

Tetreault et al. (2025) found a similar drop in smiles in autistic young adults, but their frowns did not rise. The CdLS group shows both fewer smiles and more frowns, a double hit.

Fabio et al. (2014) saw tighter, flatter ratings of emotion faces in ASD. CdLS kids do not just rate faces differently; they produce less positive affect themselves.

When you see a child with CdLS looking blank or cranky, pause before you run a joy-based program. Screen for pain, reflux, or dental issues first; these kids hurt more than they show. Then teach staff to celebrate tiny smiles and to accept neutral as their baseline. Build reinforcement systems that do not rely on big grins—use eye contact, small gestures, or access to sensory items instead.