Objective: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited syndrome; the heterozygous mutated allele is transmitted by the affected parent, regardless of gender. Some lesions are found with recessive inheritance in Algerian patients. This made us look for and study families with recessive tumors. Methods: We systematically gathered all cases of familial Multiple Endocrine Neoplasia Type 1 (MEN1) and conducted comprehensive biological and technical analyses, which included detailed inquiries into personal and familial medical histories. We meticulously tracked and investigated the transmission patterns of each lesion, following their progression from the first generation to subsequent generations. Results: In our research, we observed that only 4 types of tumors were predominantly inherited in a dominant fashion. Conversely, the majority of the other tumors and lesions associated with MEN1 exhibited a significantly recessive inheritance pattern. Conclusion: Upon observing that certain tumors were inherited from grandparents to grandchildren, skipping the parental generation (and this was in several families that were studied; especially since some families had a blood-related marriage), we raised the possibility of the presence of recessive traits in this syndrome, although in general it is dominant.