The Different Forms of Mucopolysaccharidosis with Neurological Involvement: A Case-Based Review

Abstract

The mucopolysaccharidoses (MPSs) are a group of rare lysosomal storage disorders caused by deficiency of enzymes catalyzing the stepwise degradation of glycosaminoglycans dermatan sulfate, heparan sulfate, keratan sulfate, chondroitin sulfate, and hyaluronic acid. There are seven groups of MPS, which are MPS-I (MPS-I-H or Hurler syndrome; MPS-I-S or Scheie syndrome; and MPS-I-HS or Hurler?Scheie syndrome), MPS-II (Hunter syndrome), MPS-III (Sanfilippo syndrome types A to D), MPS-IV (Morquio syndrome types A and B), MPS-VI (Maroteaux?Lamy syndrome), MPS-VII (Sly syndrome), and MPS-IX (Natowicz syndrome). All are inherited as autosomal recessive diseases, with the exception of Hunter syndrome, which follows an X-linked recessive inheritance pattern. The MPSs affect multiple organ systems (including bone, heart, and visceral organs), leading to organ failure. Involvement of central nervous system occurs only in the forms with heparan sulfate accumulation, that is, MPS-I, MPS-II, MPS-III, and MPS-VII. Therapy is available for MPS-I, MPS-II, MPS-IV, and MPS-VI. This review provides a case-based overview of the different forms of MPS with neurological involvement.

Cardiac involvement in MPS patients: incidence and response to therapy in an Italian multicentre study

“…Patients with MPS generally appear normal at birth, but later on they may develop multiple clinical manifestations including coarse facial features, skeletal abnormalities leading to growth impairment, poor joint range of motion, organomegaly, corneal clouding, hearing loss, valvular heart disease, cardiac hypertrophy. Also neurological involvement is present in MPS IH (Hurler), in the severe forms of MPS II and VII, in most MPS III patients [ 2 , 3 ]. MPS diagnosis proceeds from clinical suspicion, going through biochemical analysis, including urinary GAGs and enzymatic assays, and finally is confirmed by molecular diagnosis.…”