Next Topic Signs and Symptoms of Sanfilippo Syndrome

All four types of Sanfilippo syndrome produce relatively mild physical symptoms but more serious neurological problems. However, specific signs, symptoms, and disease progression are not determined by the type of enzyme deficiency. The disease is complex and variable, with a spectrum of rapidly progressive disease (severe) and slowly progressing disease (attenuated). Unfortunately, there is no reliable way to predict disease severity. Even with the same amount of enzyme activity, and within the same family, there can be variations.

Infants usually show no signs of Sanfilippo syndrome, but symptoms typically appear gradually between 2 and 6 years of age. Diagnosis may be delayed, as some children do not have abnormal features, and their symptoms are nonspecific with little evidence to suggest a mucopolysaccharidoses (MPS) disease.

As the disease progresses, children develop extreme activity, restlessness, sleeplessness, and often difficult behavior. Language and understanding will gradually be lost. Some children never become toilet trained, and those who do will eventually lose this ability. Over time, children with Sanfilippo syndrome become unsteady on their feet, tending to fall frequently as they walk or run, and eventually lose the ability to walk. Some parents report episodes of muscle spasms, dystonia (sustained muscle contractions), or continuous jerking movements. These may or may not be linked to seizures and can be difficult to treat. As Sanfilippo syndrome is a condition that worsens over time, all individuals will experience progression of symptoms regardless of initial disease severity.

Life expectancy in Sanfilippo syndrome is extremely varied. Individuals typically live into their teenage years. Some children may not live this long, while others may live into their twenties. Mildly affected individuals have lived into their thirties and, in a few rare cases, into their forties.

The table below provides an overview of the signs and symptoms that may occur in individuals who have Sanfilippo syndrome.

Overview of signs and symptoms in Sanfilippo syndrome
General symptoms
Extreme activity, restlessness, frequent chewing, and often very difficult behavior
Sleep disorders (common)
Reduced endurance over time
Becoming more unsteady on feet and eventual loss of ability to walk
Abnormal metabolism of medications (in some cases)
Increased pain tolerance
Physical appearance
Mildest physical abnormalities of the MPS diseases
Fairly normal height
Abnormal facial features (such as thick lips with upper lip upturned, fleshy nose tip, flat face, and eyes that stick out slightly) but less prevalent and pronounced than in other MPS diseases
Large heads in children but not in older patients
Thick hair and more hair than usual on body
Dark bushy eyebrows that may meet in the middle
Mouth and teeth
May have enlarged tongue
Gum ridges can be broad
May have abnormal teeth (widely spaced and poorly formed, with fragile enamel)
Eyes, ears, nose, and throat
Vision problems caused by damage to retina (may result in night blindness and loss of peripheral vision)
Hearing loss
Frequent ear infections (otitis media)
Frequent sinus infections (sinusitis)
Enlarged tonsils and adenoids that partly block the airway
Narrowed, floppy, or softer-than-usual trachea (windpipe)
Respiratory system (lungs and breathing)
Lung problems and reduced lung function
Sleep apnea (rare)
Frequent coughs and colds
Heart and blood vessels
Heart valve problems (usually mild)
Gastrointestinal system (stomach and intestines)
Slightly enlarged liver and spleen (hepatosplenomegaly)
Umbilical and inguinal hernias*
Musculoskeletal system (bones and joints)
Minimal problems with bone formation and growth
Joint stiffness
Osteoporosis at young age, increasing the risk of fractures
Hips may become dislocated (this is not often a problem)
Fingers occasionally bent due to joint stiffness
Difficulty extending arms fully
Tight Achilles tendon
Knock-knees
Broad feet, toes may be curled under
Brain and nerves
Seizures at later stage of disease
*Hernias: When part of an organ (such as the intestine) protrudes from a weak spot in the muscular wall surrounding the abdomen, producing a bulge in the skin, this is called a hernia.
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