A very rare case with Marfan syndrome born from his mother with Marfan syndrome and his father with pituitary dwarfism (type I) was described. In the maternal families the consanguinity and Marfan syndrome were present. In the paternal families the consanguinity and dwarfism were present. As a rule of Mendelian inheritance, the patient is believed to show not pituitary dwarfism as an autosomal recessive trait but Marfan syndrome as an antusomal dominant trait.