To our knowledge, this is the first systematic and comprehensive study on the natural course of mucopolysaccharidosis type IIIA. The 4-point scoring system may be used to classify patients into groups with a rapid or slower course of the disease. This may have an important impact on parental counseling as well as therapeutic interventions.

Mucopolysaccharidosis type IIIA (MPS IIIA, Sanfilippo A syndrome) is caused by mutations in the N-sulfoglucosamine sulfohydrolase (SGSH) gene and the resulting defective lysosomal degradation of the glycosaminoglycan heparan sulfate. The onset and progression of the disease are highly variable. Seventy-five mutations distributed over the SGSH gene have been described. We here report on the analysis of the natural course of the disease in 54 MPS IIIA patients through the use of a detailed questionnaire and four-point scoring system and an examination of the underlying mutations. By assessing the degree of developmental regression over time a group of seven patients with a slowly progressive course of the disease were identified. In these seven patients and in 3 other mildly affected patients the missense mutation c.892T>C (p.Ser298Pro) was found on one allele. These patients showed a lower frequency and later onset of the typical symptoms of the disease. The onset of regression in speech abilities and cognitive functions were delayed by 0.7 and 0.8 years, respectively, and the onset of regression of motor functions occurred 6.1 years later than in all other MPS IIIA patients. Severe regression in speech, cognitive and motor functions were delayed by 5, 5.9, and 11.2 years, respectively. These data suggest that in MPS IIIA patients carrying the mutation p.Ser298Pro a slowly progressive phenotype can be predicted and this may have an important impact on parental counselling and therapeutic interventions.

Background: Mowat-Wilson syndrome (MWS; OMIM #235730) is a genetic condition caused by heterozygous mutations or deletions of the ZEB2 gene. It is characterized by moderate-severe intellectual disability, epilepsy, Hirschsprung disease and multiple organ malformations of which congenital heart defects and urogenital anomalies are the most frequent ones. To date, a clear description of the physical development of MWS patients does not exist. The aim of this study is to provide up-to-date growth charts specific for infants and children with MWS. Charts for males and females aged from 0 to 16 years were generated using a total of 2,865 measurements from 99 MWS patients of different ancestries. All data were collected through extensive collaborations with the Italian MWS association (AIMW) and the MWS Foundation. The GAMLSS package for the R statistical computing software was used to model the growth charts. Height, weight, body mass index (BMI) and head circumference were compared to those from standard international growth charts for healthy children. Results: In newborns, weight and length were distributed as in the general population, while head circumference was slightly smaller, with an average below the 30 th centile. Up to the age of 7 years, weight and height distribution was shifted to slightly lower values than in the general population; after that, the difference increased further, with 50% of the affected children below the 5 th centile of the general population. BMI distribution was similar to that of non-affected children until the age of 7 years, at which point values in MWS children increased with a less steep slope, particularly in males. Microcephaly was sometimes present at birth, but in most cases it developed gradually during infancy; many children had a small head circumference, between the 3 rd and the 10 th centile, rather than being truly microcephalic (at least 2 SD below the mean). Most patients were of slender build. Conclusions: These charts contribute to the understanding of the natural history of MWS and should assist pediatricians and other caregivers in providing optimal care to MWS individuals who show problems related to physical growth. This is the first study on growth in patients with MWS.

Patients with increasing coronal and sagittal plane deformities with a high thoracic scoliosis apex are at the highest risk for reduced FVC%. The models developed provided improved estimations of actual PF based on the magnitude of the radiographical deformity.