<unk>  Types A, B, C, and D are considered to be clinically indistinguishable, although mutations in different genes are responsible for each disease. The following discussion is therefore applicable to all four conditions. A urinalysis can show elevated levels of heparan sulfate in the urine. All four types of<unk>  show increased levels of GAGs in the urine; however, this is less true of<unk>  than other MPS disorders. Additionally, urinary GAG levels are higher in infants and toddlers than in older children. In order to avoid a false negative urine test due to dilution, it is important that a urine sample be taken first thing in the morning. 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. Prenatal diagnosis is possible by chorionic villus sampling or amniocentesis.
Sanfilippo syndrome
Autism spectrum
DeSanto-Shinawi syndrome
Filippi Syndrome
Treacher Collins syndrome
Pelger–Huët anomaly
Van der Woude syndrome
Van Gogh syndrome