Determine the Frequency of Variants in the GBA/PSAP Genes in Patients With MM or MGUS

Inclusion Criteria: * Major patients with multiple myeloma (MM) (defined by clonal proliferation of tumour plasma cells (\>10%), presence of a monoclonal peak in serum or urine (excluding non-secretory myeloma) and organ involvement secondary to bone marrow invasion) or with MGUS (defined as bone marrow plasmacytosis of less than 10%, associated with a monoclonal protein of less than 30g/L and no clinical involvement). * Membership of a social security scheme * Adult having read and understood the information letter and signed the consent form Exclusion Criteria: * Person deprived of liberty by an administrative or judicial decision or person placed under court protection / sub-guardianship or guardianship