Benefits of Newborn Screening Benefits of early treatment: However, they are current clinical trials addressing both the body and the brain, such as gene therapy, intrathecal dosing, and some promising new technologies. It is not a cure for the disease nor will fix damage done prior to taking the treatment. Idursulfase (Elaprase) is given weekly as an IV infusion to deliver the recombinant I2S protein in order to breadown the GAGs. However, current ERT treatments do not cross the blood-brain barrier. Treatment:Įnzyme replacement therapy (ERT) is the only available treatment that will slow the systemic progression of the disease. If a mutation is not found, the child is not diagnosed with MPS-II. If the test fails to identify a known pathogenic variant, deletion/duplication analysis or complex rearrangements are done to identify the mutation. The first test is a sequence analysis, which identifies a known pathogenic variant in 82 percent of the confirmed cases. Genetic testing confirms the IDS gene mutations. Urine testing measures the glycosaminoglycan (GAG) urinary tract excretion levels.

Confirmation testing consists of either urine or genetic testing. If the initial screening method is positive, confirmation testing is needed. A positive screen for MPS-II is an I2S activity less than or equal to 10 percent of the daily median. Tandem mass spectrometry (MS/MS), available in multiplex, is used to test for the daily median. Diagnostic Testingĭried blood samples (DBS) are used for the initial screening, testing for the enzymatic activity of the I2S protein. Primary samples of blood or saliva are collected for DNA extraction. Individuals with attenuated MPS-II typically do not develop intellectual disabilities and can live into adulthood. Symptoms typically begin occurring between the ages of three and six. Severe MPS-II children begin showing symptoms between the ages of one and four, with intellectual regression occurring within the ages of three to five, and passing away generally within the first ten to fifteen years of life.Īttenuated MPS-II has a wide range in progression of the disease. Physical symptoms are similar between severe and attenuated MPS-II, with onset of the disease varying. Enlarged vocal cords, which results in a deep, hoarse voice.Intellectual disabilities found in severe MPS-II patients.Signs and symptoms for those not receiving treatment are many and variable, but most commonly include: There are approximately 500 boys in the US with MPS II and 2,000 worldwide. Severe MPS-II is more common than attenuated MPS-II, with two out of three boys diagnosed with the severe form. MPS-II occurs in approximately 1 in 100,000-170,000 births, primarily in males. Therefore, the X-linked nature of inheritance results in MPS-II affecting males more than females. The female will be a carrier of MPS-II but usually she herself will have few, if any, symptoms. If a female has one X chromosome that has the I2S gene mutation, most cells in the body will generally “inactivate” that X chromosome with the mutation. Men have only one X chromosome (XY), resulting in men only having one copy of the IDS gene. Females are born with two X chromosomes (one from their mother and one from their father). MPS-II follows a X-linked inheritance pattern, which means that the IDS gene is located on the X chromosome. MPS-II is divided into two forms: neuronopathic MPS-II (severe) and non-neuronopathic (attenuated) MPS-II. The buildup of GAGs can physically enlarge cells and the organs they make up as well as disrupt movement of other molecules in the cell. Without a functioning level of I2S enzyme, GAGs build up within organelles inside cells called lysosomes.

The disease is caused by mutations of the IDS gene causing a shortage/elimination of the I2S enzyme, which helps to decrease levels of sugar molecules called glycosaminoglycans (GAGs) within cells. MPS-II is a rare, progressive, genetic lysosomal storage disorder that affects many parts of the body including the airways, head, heart, brain, spleen, and liver.

Rare Disease Legislative Advocates (RDLA).

Newborn Screening Saves Lives Reauthorization Act.

Mps disease