NCAM1 and chronic inflammatory demyelinating polyradiculoneuropathy: For example, missense loss-of-function mutations in perforin have been identified in some CIDP patients (Buttini et al., 2015), and a study of 22 CIDP patients and 22 healthy controls showed the proportion of CD3– CD56+ NK cells was lower in the blood of patients (Sanvito et al., 2009).