Musculoskeletal manifestations of Sanfilippo Syndrome (mucopolysaccharidosis type III)

The most pronounced symptom in mucopolysaccharidosis type III (MPS III, Sanfilippo Syndrome) is the severe neurocognitive deterioration of the central nervous system. The effects of MPS III on the musculoskeletal system are less severe than those caused by other forms of MPS, however, it is our experience that many families seek orthopaedic attention for perceived musculoskeletal discomfort, particularly about the hip and spine. The purpose of this study is to report musculoskeletal findings in a case series of patients with MPS III.

This study represents a retrospective case series of all records available from 2 institutions on patients with MPS III. Chart and radiographic review was performed and outcomes tabulated. Our hypotheses are: (1) Musculoskeletal abnormalities are prevalent in children with MPS III and (2) Musculoskeletal deformities in children with MPS III may require surgical intervention.

Eighteen patients were identified (10 female and 8 male) with an average age of 10.3 years. Three had significant scoliosis (21 to 99 degrees) and 2 others had L1 hypoplasia. Four patients had osteonecrosis of the femoral heads. One patient required a carpal tunnel release, and another a trigger thumb release. There were no cases of cervical instability.

In our study with these patients, we have observed several unreported musculoskeletal manifestations of MPS III. Osteonecrosis of the hips can be a source of severe discomfort for these children. Although uncommon, operative intervention for orthopaedic conditions is sometimes warranted. Operative indications in this cohort include progressive scoliosis of large magnitude, carpal tunnel syndrome, and trigger digits.

Level IV; case series.