Mal de Meleda (MDM) is an autosomal recessive palmoplantar keratoderma associated with mutations in a gene encoding secreted Ly6/uPAR-related protein-1 (SLURP-1). SLURP-1 controls growth, differentiation, and apoptosis of keratinocytes by interaction with α7 type nicotinic acetylcholine receptors (α7-nAChRs). SLURP-1 has a three-finger structure with the β-structural core ('head') and three prolonged loops (fingers). To determine a role of SLURP-1 mutations, we produced 22 mutant variants of the protein, including those involved in MDM pathogenesis. All mutants except R71H, R71P, T52A, R96P, and L98P were produced in the folded form. SLURP-1 reduces a growth of Het-1A keratinocytes, thus we studied an influence of the mutations on its antiproliferative activity. Mutations in the loops I and III led to the protein inactivation, while majority of mutations in the loop II increased SLURP-1 antiproliferative activity. Alanine substitutions of R96 and L98 residues located in the protein 'head' resulted in appearance of additional proapoptotic activity. Our results agree with the diversity of MDM phenotypes. Using obtained functional data, the SLURP-1/α7-nAChR complex was modelled in silico. Our study provides functional and structural information about the role of the SLURP-1 mutations in MDM pathogenesis and predicts SLURP-1 variants, which could drive the disease.