Mucopolysaccharidosis type IIIA (MPS IIIA), also known as Sanfilippo syndrome type A, is a subtype of MPS III and is considered the most severe form of MPS III. The features of MPS IIIA are due to the build up of glycosaminoglycans (GAGs), important complex carbohydrates responsible for many regulatory functions in the body. This build up primarily affects the central nervous system. Although symptoms can range from mild to severe, even among affected individuals in the same family.
Infants with MPS IIIA appear normal at birth. Developmental delay and speech delay typically begin before 1 year of age, with the average age of onset at 7 months. Recurrent ear, nose, and throat infections are common. Behavioral issues, such as aggressiveness, sleeplessness, and hyperactivity typically develop in early childhood, often between ages 3 and 5 years. Intellectual disability becomes more severe during this time period, in part, because seizures frequently develop. Verbal communication is often lost before age ten. Motor problems, such as difficulty swallowing and spasticity (stiff or rigid muscles) will also develop. Most individuals with MPS IIIA lose the ability to walk by their mid-teens. Hearing loss is common. The physical features of the disease, such as coarse facial features, skeletal abnormalities, and macrocephaly (large head) are often mild.
The incidence of MPS IIIA varies significantly by region. Where estimates have been made, the incidence ranges from 1 in 60,000 to 1 in 4,600,000, with an average incidence of approximately 1 in 172,000.
There is currently no approved treatment or cure for MPS IIIA.
MPS IIIA is a condition with chronic issues and limited treatment options. Death typically occurs by the second or third decade of life, with an average lifespan of approximately 15 years.
The mission of the National MPS Society is to support research, support families, and to increase public and professional awareness for people with MPS disorders.
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