Mucopolysaccharidosis VII (MPS VII) is a rare, genetic disease that is usually inherited as an autosomal-recessive trait. Genetic mutations affect mental retardation, skeletal deformities, corneal clouding, hepatosplenomegaly and intelligence. To date, several genes have been found in related to patients with MPS VII. Here, we used whole-exome sequencing to identify a mutation (NC_000007.13:g. 65444706G>A) in GUSB gene in an eight year old boy with MPS VII. Subsequently, we speculated that the variant of GUSB gene is critical for the proper function of GUSB, and might had led to an absence of the β-glucuronidase or reduce activity of the enzyme.