What is Sanfilippo Syndrome?
Sanfilippo Syndrome is an extremely rare genetic medical condition which affects the overall metabolism of the body. This condition comes under mucopolysaccharidosis III. All conditions that come under the category of MPS lack a vital enzyme in the body which eventually leads to accumulation of complex sugar molecules affecting the metabolic rate and functioning of vital organs of the body .
Sanfilippo Syndrome can be subdivided into four different categories based on the enzyme that is missing or malfunctioning.
Type A: This form of Sanfilippo Syndrome is the most common in children. It is the most severe form of this condition and has a relatively poor prognosis. Heparan N-sulfatase is the enzyme that is dysfunctional or missing in cases of Sanfilippo Syndrome Type-A.
Type B: This is the second most common form of the condition seen. It results due to missing enzyme N-acetyl-alpha-D-glucosaminidase. Its symptoms are severe and prognosis poor but when compared to the Type A variant the symptoms are less severe
Type C&D: These forms of Sanfilippo Syndrome are extremely rare. 
The symptoms of Sanfilippo Syndrome are not apparent immediately after the birth of the child as the condition is progressive in nature. The symptoms start to appear as the sugar molecules accumulate in the body which normally happens after six to seven months of age. 
With time as the condition progresses the brain gets affected and the child shows regression in brain function along with inability to walk, speak, and carry out basic activities like eating and playing. 
The disease progresses ultimately to such a level where the child is totally dependent on others for basic activities. This article informs about the prevalence of Sanfilippo Syndrome across United States, the treatment strategies, and the overall prognosis. 
How Common is Sanfilippo Syndrome in the United States?
As stated, Sanfilippo Syndrome comes under the conditions listed in mucopolysaccharidosis of which this condition is type III. It has been estimated that around 1 in 70,000 newborns have this condition. In majority of the cases, the child suffers from type A or B of Sanfilippo Syndrome. 
This condition is autosomal recessive meaning that one copy of the defective gene needs to be inherited from either parent to get it. For parents who are carriers of the defective gene there are 25% chances of their child being born with Sanfilippo Syndrome. There is less than 0.1% chance of unaffected children to be carriers of this condition. 
Is There a Cure for Sanfilippo Syndrome and What is its Overall Prognosis?
As of now, there is no cure for Sanfilippo Syndrome, as is the case with most genetic conditions. Research is still ongoing to come to a definite treatment for Sanfilippo Syndrome and many clinical trials have already been conducted with some efficacy and positivity in the results. 
Out of all investigative therapies, the most efficacious so far has been gene therapy which has shown extremely positive results in patients with Sanfilippo Syndrome.
Otherwise, the treatment for this condition is mostly symptomatic and supportive aimed at controlling the symptoms and improving the quality of life of the patient. 
This requires a multidisciplinary approach with inputs from various specialties including neurologists, speech therapy, physical therapy, neurosurgeons, and orthopedists. Sanfilippo Syndrome affects the central nervous system causing significant damage to the brain. 
Over time, the brain gets continuously damaged and ultimately the patient loses the ability to speak and move around. There is also growth and mental retardation along with hyperactivity, insomnia, seizures, and cardiac conditions.
All these complications ultimately results in the patient succumbing to the condition. The overall prognosis of an individual with Sanfilippo Syndrome is approximately 10 years with maximum life of only 20 years at most. 
In summary, Sanfilippo Syndrome is the most common form of MPS-III disorder caused by gene that produces enzyme which is involved in breakdown of complex sugar molecules which is vital for functioning of various vital organs of the body and the overall metabolic process.
Around 1 in every 70,000 births newborns have Sanfilippo Syndrome making it a rare condition. It is inherited as an autosomal recessive pattern meaning that one copy of the defective gene is inherited from each parent for the child to get this condition.
As of now there is no cure for this condition and treatment is asymptomatic and supportive. With no specific treatment available, the overall prognosis for Sanfilippo Syndrome is around 10-20 years with most children not being able to live beyond 20 years of age. This is due to the progressive nature of Sanfilippo Syndrome and the damage it causes to organs like the brain and the heart.