PLACK syndrome associated with alopecia areata and a novel homozygous base pair insertion in exon 18 of CAST gene

This study reports a novel case of PLACK syndrome in an 11-year-old boy, associated with alopecia areata and a new homozygous mutation in the CAST gene. PLACK syndrome is a rare autosomal recessive condition characterized by skin peeling, blisters, and other dermatological symptoms. The identified mutation in exon 18 of the CAST gene leads to a frameshift and premature protein truncation, affecting calpastatin, which regulates calpain activity. This mutation may contribute to increased calpain activity, impairing skin adhesion and potentially linking to autoimmune conditions like alopecia areata. The study suggests that individuals with PLACK syndrome may be predisposed to autoimmune diseases if there is an associated PTPN22 polymorphism, although further research is needed to explore the direct effects of CAST gene mutations on immune responses.