title: Natural history of Sanfilippo syndrome in Spain.
abstract: BACKGROUND
  Mucopolysaccharidosis type III (MPS III), or Sanfilippo syndrome, is caused by a deficiency in one of the four enzymes involved in the lysosomal degradation of heparan sulphate. Four MPS III types have been recognized, characterized by a large phenotypic heterogeneity. This is the first Spanish study describing the natural history of Sanfilippo patients (MPSIIIA, MPSIIIB and MPSIIIC), representing an essential step for understanding patient prognosis and for the establishment and application of future therapies.
  
  
  METHODS
  This retrospective study aimed to establish the natural history of MPS III in Spain based on an extensive chronological data survey involving physicians and parents of 55 Spanish MPSIII patients. In addition to clinical description we report biochemical and molecular analysis already performed in the majority of cases.
  
  
  RESULTS
  The most frequent subtype was MPS IIIA (62%). Symptoms before diagnosis were speech delay in 85%, followed by coarse facial features in 78%, and hyperactivity in 65% of cases at a mean age of 3 years old. The median age at clinical and biochemical diagnosis for each MPS III subtype were as follows: IIIA 4.4 years (1.2 - 16 years), IIIB 3.1 years (1-29 years), and IIIC 6.3 years (3.4-22 years).45% of patients developed epilepsy at a median age of 8.7 (2.5 - 37) years old.Age of death for MPS IIIA patients was 15 years (11.5 - 26 years).Molecular analysis of our cohort reveals, as alluded to above, a great allelic heterogeneity in the three subtypes without clear genotype-phenotype correlations in most cases.
  
  
  CONCLUSIONS
  MPS IIIA is the most frequent subtype in Spanish Sanfilippo patients. Diagnosing physicians should consider Sanfilippo syndrome in children with non-specific speech delay, behavioural abnormalities, and/or mild dysmorphic features. We stress the importance of establishing early diagnosis procedures as soon as possible so as to be able to determine future short-term enzymatic or gene therapy treatments that can change the prognosis of the disease.
authors: Neuropediatrics Department, Hospital Sant Joan de Déu, Barcelona, Spain. vdelgadillo@hsjdbcn.org.
authors: Verónica
authors: V
authors: Delgadillo
authors: Maria del Mar
authors: Mdel M
authors: O'Callaghan
authors: Laura
authors: L
authors: Gort
authors: Maria Josep
authors: MJ
authors: Coll
authors: Mercedes
authors: M
authors: Pineda
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009084:Mucopolysaccharidosis III / Q000175:diagnosis / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult