Regional brain atrophy in gray and white matter is associated with cognitive impairment in Myotonic Dystrophy type 1

AbstractMyotonic dystrophy type 1 (DM1) is a multi-system disorder caused by CTG repeats in the myotonic dystrophy protein kinase (DMPK) gene. This leads to sequestration of the splicing factor, muscleblind-like 2 (MBNL2), and aberrant splicing, mainly in the central nervous system. We investigated the splicing patterns of MBNL1/2 and genes controlled by MBNL2 in several regions of the brain and between the grey matter (GM) and white matter (WM) in DM1 patients using RT-PCR. Compared with the control, the percentage of spliced-in parameter (PSI) for most of the examined exons were significantly altered in most of the brain regions of DM1 patients, except for the cerebellum. The splicing of many genes was differently regulated between the GM and WM in both DM1 and control. The level of change in PSI between DM1 and control was higher in the GM than in the WM. The differences in alternative splicing between the GM and WM may be related to the effect of DM1 on the WM of the brain. We hypothesize that in DM1, aberrantly spliced isoforms in the neuronal cell body of the GM may not be transported to the axon. This might affect the WM as a consequence of Wallerian degeneration secondary to cell body damage. Our findings may have implications for analysis of the pathological mechanisms and exploring potential therapeutic targets.

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Brain imaging in myotonic dystrophy type 1

Neurology ◽

10.1212/wnl.0000000000004300 ◽

2017 ◽

Vol 89 (9) ◽

pp. 960-969 ◽

Cited By ~ 29

Author(s):

Kees Okkersen ◽

Darren G. Monckton ◽

Nhu Le ◽

Anil M. Tuladhar ◽

Joost Raaphorst ◽

...

Keyword(s):

White Matter ◽

Brain Imaging ◽

Longitudinal Studies ◽

Myotonic Dystrophy ◽

Gray Matter ◽

Myotonic Dystrophy Type 1 ◽

Myotonic Dystrophy Type ◽

Pooled Prevalence ◽

The Brain

Objective:To systematically review brain imaging studies in myotonic dystrophy type 1 (DM1).Methods:We searched Embase (index period 1974–2016) and MEDLINE (index period 1946–2016) for studies in patients with DM1 using MRI, magnetic resonance spectroscopy (MRS), functional MRI (fMRI), CT, ultrasound, PET, or SPECT. From 81 studies, we extracted clinical characteristics, primary outcomes, clinical-genetic correlations, and information on potential risk of bias. Results were summarized and pooled prevalence of imaging abnormalities was calculated, where possible.Results:In DM1, various imaging changes are widely dispersed throughout the brain, with apparently little anatomical specificity. We found general atrophy and widespread gray matter volume reductions in all 4 cortical lobes, the basal ganglia, and cerebellum. The pooled prevalence of white matter hyperintensities is 70% (95% CI 64–77), compared with 6% (95% CI 3–12) in unaffected controls. DTI shows increased mean diffusivity in all 4 lobes and reduced fractional anisotropy in virtually all major association, projection, and commissural white matter tracts. Functional studies demonstrate reduced glucose uptake and cerebral perfusion in frontal, parietal, and temporal lobes, and abnormal fMRI connectivity patterns that correlate with personality traits. There is significant between-study heterogeneity in terms of imaging methods, which together with the established clinical variability of DM1 may explain divergent results. Longitudinal studies are remarkably scarce.Conclusions:DM1 brains show widespread white and gray matter involvement throughout the brain, which is supported by abnormal resting-state network, PET/SPECT, and MRS parameters. Longitudinal studies evaluating spatiotemporal imaging changes are essential.

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