Eleven mothers of 12 patients with MPS (MPS-I = 1; MPS-II = 3; MPS-III = 3; MPS-IV = 4; and MPS-VI = 1) were included. The average WHOQOL-BREF score was 46.59, with the physical health domain scoring highest and the environmental domain scoring lowest. The lower QoL of mothers of children with MPS-II seems to be related to the worse clinical condition of these children, with more severe symptoms and greater need for help with daily activities as well as with a feeling of responsibility due to the inheritance pattern of the disease.