Defining Sanfilippo Syndrome
Sanfilippo syndrome is a form of inherited disease involving a person's metabolism. The disease makes a person's body unable to appropriately break down long chains of sugar molecules referred to as, 'glycosaminoglycans.' The syndrome is one of a group of diseases known as, 'mucopolysaccharidoses,' or MPS. Sanfilippo syndrome is also known as MPS III.
Sanfilippo syndrome tends to be fatal before the age of twenty years, although there are a few exceptions, and it is currently not a disease that is curable. A diagnosis of the disease is usually reached within the first few years of a person's life when a child does not develop as they might be be expected to, or they start to experience losses in developmental achievements.
Causes of Sanfilippo Syndrome
Sanfilippo syndrome occurs when the enzymes that are needed to break down the heparan sulfate sugar chain are either defective, or missing entirely. There are four main types of Sanfilippo syndrome, also referred to as MPS III. The type of the syndrome a person has is dependent upon which enzyme is affected.
Sanfilippo type A is the most severe form of the syndrome. Persons with this type are either missing, or have an altered form of, an enzyme called, 'heparan N-sulfatase.'
Sanfilippo type B occurs when a person is either missing, or doesn't not produce enough, alpha-N-acetylglucosaminidase.
Sanfilippo C occurs when a person is either missing, or doesn't not produce enough, acetyl-CoAlpha-glucosaminide acetyltransferase.
Sanfilippo D occurs when a person is either missing, or doesn't not produce enough, N-acetylglucosamine 6-sulfatase.
Sanfilippo syndrome is inherited as an autosomal recessive trait. What this means is that both of the parents of the person who has been affected by the disease have passed them the defective gene.
Symptoms of Sanfilippo Syndrome
There is usually no way for parents to determine that their child has been born with Sanfilippo syndrome that are present - unless the disease has been suspected and the parents have pursued genetic testing. Some children with the syndrome present with a larger head than average, although many children seem to be just fine. After their first year of life, children with Sanfilippo syndrome can experience symptoms that may become more evident. These symptoms may include chronic diarrhea, agitation, poor behavior, as well as a failure to make developmental gains. Some children with the syndrome can also experience seizures, stiffness in their legs, and joint problems. They may develop confusion or dementia, and could be prone to respiratory infections.
There are some children with Sanfilippo syndrome who have characteristic appearance markers which may suggest the disease, such as a larger head. Others might have more adult looking facial features, fuller lips, or a heavy eyebrow that could be thick and meet in the middle. Their hair might also be courser, or more profuse in its growth than could usually be expected in a child.
Children with Sanfilippo syndrome usually experience a decline in their ability to learn between the ages of two and six years. They might experience an average rate of growth for their first few years of life, but their final height is commonly below average. Developmental delays experienced by children with Sanfilippo syndrome are usually followed by a deterioration in their mental status.
Symptoms of Sanfilippo syndrome can include:
Coarse facial features
Stiff joints that may not extend fully
Heavy eyebrows that meet in the middle of the face
Diagnosing Sanfilippo Syndrome
Sanfilippo syndrome is usually identified as an inherited disorder. While the parents of a child with the syndrome do not have the syndrome themselves, they each have a recessive gene for it. The gene is passed to their child, something that is referred to as an, 'autosomal recessive inheritance pattern.' People who are aware that someone in their family has, or has had, Sanfilippo syndrome - to include cousins, aunts or uncles, should consider receiving testing with their partner before conceiving a child. Both of the parents need to have the gene for Sanfilippo syndrome in order for the syndrome to be passed to a child. Even if one parent has it, it should be noted that the next generation of children needs to be aware that they might carry the recessive gene.
The degree to which Sanfilippo syndrome progresses can be determined by the type of the syndrome involved. There are four types of Sanfilippo syndrome, labeled A through D. Each one of the types represents a lack of a particular enzyme that makes it difficult for the affected person to break down long chain sugars. The type of Sanfilippo syndrome a person has could, in part, determine the outcome. Sanfilippo syndrome type A is many times considered to be both the most common type of the syndrome, as well as the most severe.
A physical examination can demonstrate signs of either spleen or liver swelling in a person with Sanfilippo syndrome. Eye examination shows clear corneas in persons with the syndrome. Neurological testing in relation to people with the syndrome reveals signs of mental retardation and seizures. Urine testing can also be performed, and people with Sanfilippo syndrome have large amounts of mucopolysaccharide, referred to as, 'heparan sulfate,' in their urine. Additional testing related to Sanfilippo syndrome can include:
Slit lamp eye exam
X-rays of the bones
Skin fibroblast culture
Treatment of Sanfilippo Syndrome
There is currently no cure for Sanfilippo syndrome. People with the syndrome and their family members find that support from physical therapists, occupational therapists, and doctors can be vital. Forms of medical treatments can help to ease some of the conditions associated with the syndrome, although they will not fully-alter the course of the disease itself. Caregivers will also need supports, as well as other children in the family who do not have the disease and might benefit from counseling and support. Behavioral issues can be problematic for the entire family, and the prospect of losing a sibling particularly troubling.
The best possible treatment would be a way to cure the illness, of course; but a cure remains elusive. Due to the fact that a cure has not been discovered by medical science, children diagnosed with Sanfilippo syndrome often live short lives. New treatments in gene and stem cell therapies that are in development could mean that someday Sanfilippo syndrome will become a treatable condition.
Complications of Sanfilippo syndrome can include blindness, mental retardation, nerve damage that slowly worsens and eventually requires wheelchair use, and seizure activity. People affected by the syndrome can have I.Q.'s below 50. Many people with Sanfilippo syndrome do live into their teenage years, although some people live longer. Others die at a younger age.