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.

Dissecting the genotype in syndromic intellectual disability using whole exome sequencing in addition to genome-wide copy number analysis

When a known microimbalance affecting multiple genes is detected in a patient with syndromic intellectual disability, it is usually presumed causative for all observed features. Whole exome sequencing (WES) allows questioning this assumption. In this study of three families with children affected by unexplained syndromic intellectual disability, genome-wide copy number and subsequent analyses revealed a de novo maternal 1.1 Mb microdeletion in the 14q32 imprinted region causing a paternal UPD(14)-like phenotype, and two inherited 22q11.21 microduplications of 2.5 or 2.8 Mb. In patient 1 carrying the 14q32 microdeletion, tall stature and renal malformation were unexplained by paternal UPD(14), and there was no altered DLK1 expression or unexpected methylation status. By WES and filtering with a mining tool, a novel FBN1 missense variant was found in patient 1 and his mother, who both showed clinical features of Marfan syndrome by thorough anthropometric assessment, and a novel EYA1 missense variant as a probable cause of the renal malformation in the patient. In patient 2 with the 22q11.21 microduplication syndrome, skin hypo- and hyperpigmentation and two malignancies were only partially explained. By WES, compound heterozygous BLM stop founder mutations were detected causing Bloom syndrome. In male patient 3 carrying a 22q11.21 microduplication inherited from his unaffected father, WES identified a novel missense variant in the OPHN1 X-linked intellectual disability gene inherited from the unaffected mother as a possible additional cause for developmental delay. Thus, WES seems warranted in patients carrying microdeletions or microduplications, who have unexplained clinical features or microimbalances inherited from an unaffected parent.

Neural correlates of the volitional regulation of the desire for food

OBJECTIVE

In this study, we investigate the brain mechanisms of the conscious regulation of the desire for food using functional magnetic resonance imaging. Further, we examine associations between hemodynamic responses and participants' cognitive restraint of eating (CRE), as well as their susceptibility to uncontrolled eating.

SUBJECTS

Seventeen non-vegetarian, right-handed, female Caucasian participants (age: 20-30 years, mean 25.3 years±3.1 s.d.; BMI: 20.2-31.2 kg m(-2), mean 25.1±3.5 s.d.).

MEASUREMENTS

During scanning, our participants viewed pictures of food items they had pre-rated according to tastiness and healthiness. Participants were either allowed to admit to the desire for the food (ADMIT) or they were instructed to downregulate their desire using a cognitive reappraisal strategy, that is, thinking of negative long-term health-related and social consequences (REGULATE).

RESULTS

Comparing the hemodynamic responses of the REGULATE with the ADMIT condition, we observed robust activation in the dorsolateral prefrontal cortex (DLPFC), the pre-supplementary motor area, the inferior frontal gyrus (IFG), the dorsal striatum (DS), the bilateral orbitofrontal cortex (OFC), the anterior insula and the temporo-parietal junction (TPJ). Activation in the DLPFC and the DS strongly correlated with the degree of dietary restraint under both conditions.

CONCLUSION

Cortical activation in the DLPFC, the pre-supplementary motor area and the inferior frontal gyrus (IFG) are known to underpin top-down control, inhibition of learned associations and pre-potent responses. The observed hemodynamic responses in the lateral OFC, the DS, the anterior insula and the TPJ support the notion of reward valuation and integration, interoceptive awareness, and self-reflection as key processes during active regulation of desire for food. In conclusion, an active reappraisal of unhealthy food recruits the brain's valuation system in combination with prefrontal cognitive control areas associated with response inhibition. The correlations between brain responses and CRE suggest that individuals with increased cognitive restraint show an automatic predisposition to regulate the hedonic aspects of food stimuli. This cognitive control might be necessary to counterbalance a lack of homeostatic mechanisms.

Array-CGH in unclear syndromic nephropathies identifies a microdeletion in Xq22.3-q23

To investigate whether submicroscopic chromosomal deletions or duplications can be causative of unclear syndromic nephropathies, we analyzed ten patients with congenital abnormalities of the kidney and urinary tract or glomerulopathies combined with important extrarenal anomalies by whole-genome array-based comparative genomic hybridization. In a 14-year-old girl presenting with hematuria, proteinuria, mental retardation (MR), sensorineural hearing loss, dysmorphisms, and epilepsy, we detected a microdeletion in chromosome Xq22.3-q23. This deletion was verified and characterized by fluorescence in situ hybridization and multiplex ligation-dependent probe amplification analyses, found to be de novo, uniallelic and 3.3 Mb in size. Electron microscopy of a kidney biopsy showed glomerular basement membrane thinning and segmental splitting of the lamina densa compatible with Alport syndrome. Cranial magnetic resonance and diffusion tensor imaging detected a severe neuronal migration disorder with double cortex formation and pronounced reduction of the fronto-occipital tract system. Thus, in one of ten patients with unclear syndromic nephropathies we identified a previously undescribed contiguous gene syndrome at Xq22.3-q23. The microdeletion contains the X-linked Alport syndrome gene COL4A5, the MR genes FACL4 and PAK3, and parts of the X-chromosomal lissencephaly gene DCX associated with double cortex formation in girls, MR, and epilepsy. The phenotype in our patient combines features of the Alport-MR contiguous gene syndrome with lissencephaly.