The diagnosis may be confirmed by enzyme assay of skin fibroblasts and white blood cells. The enzyme assay is considered the most-credible diagnostic tool because it detects whether or not the enzymes in the cellular pathway breaking down heparan sulfate is present or not, providing a definitive answer. This test is also ideal for younger patients in which collecting a viable urine sample is difficult or impossible. Another diagnostic tool can be gene sequencing. However, if the genetic mutation they carry has never been seen or recorded, the patient would receive a false negative.