Moesin deficiency was initially described in 7 male participants aged 4 to 69 years and is characterized by lymphopenia of the 3 lineages and moderate neutropenia. Genetically, 6 out of 7 participants had the same missense mutation in the moesin gene located on the X chromosome. The 7th patient has a mutation leading to the premature introduction of a STOP codon into the protein.Clinically the 7 participants with X-linked moesin-associated immunodeficiency all presented with recurrent bacterial infections of the respiratory, gastrointestinal or urinary tracts, and some had severe varicella.Therapeutically, in the absence of a molecular diagnosis and due to his SCID-like phenotype, one patient was treated with geno-identical hematopoietic stem cell transplantation . The remaining are untreated or treated with immunoglobulin substitution and/or prophylactic antibiotics. Since this study, the moesin gene has been integrated into DNA chips used for the molecular diagnosis of immune deficiencies in several countries. Physicians in Canada, the United States, Japan, South Africa and Europe have contacted us with a total of 16 known participants to date. Because of their very low severe, uncontrolled CMV infection and the absence of treatment recommendations, two 2 American participants were treated with allogeneic transplantation with severe post-transplant complications (1), and one of the participants died as a result of the transplant. Management of XMAID participants therefore varies widely from country to country, depending on age at diagnosis and clinical picture. It ranges from no treatment treatment (associated with recurrent infections and skin manifestations), IgIv substitution and/or antibiotic prophylaxis antibiotic prophylaxis, with low toxicity and apparent efficacy, and allogeneic transplantation, with all the risks risks involved (graft-related toxicity, graft versus host, disease, rejection, risk of infection). The Investigators therefore feel it is important to review the diagnosis, clinical presentation and management of X-MAID participants. The study the investigator propose will enable to understand the presentation of X-MAID participants, establish guidelines and provide the best treatment for each patient according to his or her clinical picture