Self-injurious behaviour in Cornelia de Lange syndrome: 1. Prevalence and phenomenology.

The team asked a simple question. Do people with Cornelia de Lange syndrome hurt themselves more than other people with the same IQ?

They paired each person with CdLS to a person without CdLS but with the same age, sex, and IQ. Then they counted who showed self-injury and where on the body it happened.

No fancy gadgets. Just careful matching and clear rules for what counts as mild versus serious self-injury.

Serious self-injury was just as common in both groups. CdLS did not add extra risk once IQ was held steady.

Mild hand-biting or hand-hitting did show up more in the CdLS group. The difference was small but real.

So the picture changes when you look at body target, not just yes-or-no injury.

Dugan et al. (1995) already showed that, across many diagnoses, self-injury usually serves a self-stimulation function. The new data say CdLS follows the same rule; the hand is simply the preferred spot.

Van Houten et al. (1980) warned that loose labels like "frequent SIB" hide important facts. This study answered that call by splitting mild hand-directed from serious harm and by using matched controls.

Gal et al. (2009) looked at kids with autism, ID, or sensory loss in the same year. They also found each diagnosis carries its own movement signature. CdLS now joins that list—hand focus is the signature here.

Capio et al. (2013) later mapped skin-picking topography in Prader-Willi syndrome. Together these papers form a set: rare syndromes come with predictable injury locations, but the overall rate still tracks general disability level, not the syndrome name alone.

When you see hand-biting in a client with CdLS, do not assume the behavior is automatically worse than in other clients with similar skills. Record severity and body site first. Use that detail to guide functional assessment and to set realistic goals. The behavior may look dramatic, but the numbers say it is probably on par with peers—just aimed at the hands.