I have chosen to do my report on Mucopolysaccharidoses (MPS) Disorder category Sanfilippo Syndrome Type A also known as MPSIIIA. I will explain what MPS and Sanfilippo Syndrome both are, what causes the disorder, and how it progresses. I will also provide a list of features and characteristics, and what can be done about it. In conclusion I will relate the concepts, theories, and issues of developmental psychology and focus primarily on cognitive and psychosocial development from birth through adolescence of the child with Sanfilippo Syndrome.
Sanfilippo Syndrome was first identified by Dr. Sylvester Sanfilippo in 1963. It is a rare syndrome with an occurrence rate of 1 out of every 25,000 live births. Both parents have to be carriers of the defective gene and both parents must pass that gene on to the child in order for that child to become affected. If both parents have the defective gene then there is a 1 in 4 chance of their child having Sanfilippo Syndrome. Those born to these parents, who are unaffected, also have a 2 in 3 chance of being a carrier. Mucopolysaccharides are the long chains of sugar molecules used in the building of connective tissues in the body. To break down this word and its meaning: “Muco” is a thick jelly-like consistency of the molecules found in the human body, “Poly” means many and, “Saccharide” is a term for the sugar molecule.
This syndrome is caused by a deficiency of an enzyme that breaks down Mucopolysaccharides/glycosaminoglycan (also known as GAG) heparan sulphate. GAGs are found throughout many tissues of the human body, particularly in the central nervous system. The human body is continuously replacing used materials and breaking them down for disposal. Those with MPS III are missing the enzyme which is essential in breaking down the used mucopolysaccharides. If one enzyme is absent or not working properly, a buildup of the GAG material occurs resulting in storage in the body’s cells.
Progressively, the body begins to lose functions, mental state deteriorates, and cognitive and behavioral problems emerge. Babies may show little sign of the disease, but as more and more cells become damaged, symptoms start to appear. These features usually begin to occur between 2 and 6 years; severe neurological degeneration occurs in most patients between 7 and 10 years of age, and death typically occurs sometime during the third stage of the disease usually by age 12 years old. Type A has been reported to be the most common and severe, with earlier onset and rapid progression of symptoms and shorter survival. Depending on how quickly the child regresses will determine their life span.
Below is a list of some of the features which have been identified in children with Sanfilippo syndrome: enlarged head, coarse facial features, coarse hair, excessive hair growth, joint stiffness, progressive ataxia (failure of muscle coordination), bulbar dysfunction, dementia, seizures, tremors, recurrent upper respiratory tract infections, severe diarrhea, or constipation, failure to thrive, severe conductive hearing loss, hyperactivity, aggressive and destructive behavior, poor attention span, temper tantrums, physical aggression, speech and language delay, sleep disturbance, severe intellectual impairment most often before 6 years of age, partial paralysis of all four limbs, growth retardation, and vision impairment.
Since every child is unique, each child is affected differently by Sanfilippo Syndrome. Some children progress much faster than others depending on the type of Sanfilippo syndrome they have. Usually the changes are very gradual making it a little easier for the parents to adjust. Sanfilippo A seems to have three main stages. Keep in mind as stated in the beginning that each child is different and will show and experience symptoms differently or not at all.
The first stage tends to be very frustrating for parents as their child begins to lag behind other children their age developmentally. Often children who suffer from this syndrome do not look abnormal and because their symptoms tend to be common among other children their age, the diagnosis tends to be made very late.
During the second phase, the child becomes extremely active, restless and difficult to parent due to tantrums and destructive behavior. Many do not require much sleep and will be into everything. Some children also begin to chew on anything they can get their hands on, like their hands or clothing. During this phase, language skills begin to decline characterized by forgetting simple words they used before when speaking. Their understanding will also be affected which makes it very hard to hold a conversation with them. However, the use of sign language and other technology enables children to communicate while they are still able to do so. One other trait indicative of the second phase is the loss of the ability to go to the bathroom. Some children with Sanfilippo never become toilet trained, and those that do tend to lose it within this stage which usually occurs during the ages of 4 to 6 years old.
When the child reaches the third stage of the Sanfilippo Syndrome their bodies begin to slow down. They become unsteady on their feet causing them to fall frequently. In time, they lose their ability to walk all together. As this happens, their mental capacity also diminishes due to worsening seizure activity, as well as their loss of vision, and hearing, the child eventually becomes immobile and finally falls into a coma like state.
Bone marrow transplants have been tried on MPS III patients, but with disappointing results. Various experimental methods have been used to try to replace the missing enzyme, but at present none have been shown to have any significant long-term benefit. At present, there is no known cure for Sanfilippo Syndrome. But currently there is hope for the future for these children thanks to the work of Dr. Fu at the Center For Gene Therapy, Columbus Childrens Research Institute, Dept. Of Pediatrics, Ohio State University.
She feels that they have therapy that will provide meaningful benefits that have occurred in their clinical trial study of MPSIIIB in an animal model also that largely the same technique could be used for those with MPSIIIA. Most importantly, the time has come for transferring the AAV (adeno-associated virus vector) which is the vehicle carrying genes into the cells that contain the missing enzyme in the gene to be applied to human clinical application. In conclusion I have learned there is hope for all those with Mucopolysaccharidoses Disorder and now for Sanfilippo Syndrome types A and B.