Hematopoietic stem cell transplantation in mucopolysaccharidosis type IIIA: A case description and comparison with a genotype-matched control group

BACKGROUND

Mucopolysaccharidosis type IIIA (MPS IIIA, Sanfilippo A syndrome) is a chronic progressive neurodegenerative storage disorder caused by a deficiency of lysosomal sulfamidase. The clinical hallmarks are sleep disturbances, behavioral abnormalities and loss of cognitive, speech and motor abilities. Affected children show developmental slowing from the second year of life, dementia occurs by the age of 5 years followed by death in the second decade of life. Only a few studies concerning HSCT in MPS IIIA have been published and do not document a clear benefit of treatment.

METHODS

The present study summarizes the clinical outcome of a girl with MPS IIIA who received HSCT at the age of 2.5 years. Her clinical course was compared with the natural history of six untreated MPS IIIA patients carrying the same mutations (p.R74C and p. R245H) in the SGSH-gene.

RESULTS

Eight years after successful HSCT, the patient showed a global developmental delay. However, cognitive abilities continued to develop, albeit very slowly. There was no sign of regression. She could talk in short sentences, had good motor abilities and performed basic daily living activities by herself. She did not present with sleeping problems, but behavioral abnormalities were profound. In contrast, the six untreated patients with identical mutations in the SGSH-gene showed the typical progressive course of disease with early and continuous loss of abilities.

CONCLUSIONS

The present data suggest a beneficial effect of HSCT performed at an early stage of MPS IIIA on cognitive skills, motor function and quality of life.

Evolution of Immune Checkpoint Blockade-Induced Myocarditis Over 2 Years

Ipilimumab and nivolumab for melanoma induced smoldering myocarditis remitting with steroids. Rechallenge with nivolumab produced steroid-refractory myocarditis confirmed by electron microscopy. Tacrolimus and mycophenolate transiently reduced inflammation, but antithymocyte globulin induced remission. Cardiomyopathy with fatty infiltration ensued, but the patient succumbed to rampant melanoma progression after lymphocyte depletion. (Level of Difficulty: Advanced.).