Magnetic Resonance of Myelin, Myelination, and Myelin Disorders

Knaap, Marjo S. van der; Valk, Jacob

doi:10.1007/978-3-662-03078-3

Cited by 177 publications

(165 citation statements)

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“…Skeletal abnormalities remind one of Chondrodysplasia punctata type I and skin changes of X-linked ichthyosis. [1][2][3] According to the age of onset, neonatal, late infantile and juvenile disease subtypes can be distinguished. 4 Neonatal MSD is the most severe form with postnatal onset and a broad range of mucopolysaccharidosis-like clinical symptoms.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7][8] Late infantile MSD resembles late infantile metachromatic leukodystrophy with progressive loss of mental and motor abilities; these clinical features are combined with other symptoms of single sulfatase deficiencies like dysmorphism, skeletal changes and ichthyosis. 2,3,[9][10][11][12] Late infantile MSD can be subdivided into a severe (LIS) and an attenuated (late infantile mild, LIM) form, the latter showing a reduced number of symptoms and later onset beyond the second year of life. 13 Late infantile forms include the majority of MSD cases; a Saudi variant form was described separately.…”

Section: Introductionmentioning

confidence: 99%

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SUMF1 mutations affecting stability and activity of formylglycine generating enzyme predict clinical outcome in multiple sulfatase deficiency

et al. 2011

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Multiple Sulfatase Deficiency (MSD) is caused by mutations in the sulfatase-modifying factor 1 gene encoding the formylglycine-generating enzyme (FGE). FGE post translationally activates all newly synthesized sulfatases by generating the catalytic residue formylglycine. Impaired FGE function leads to reduced sulfatase activities. Patients display combined clinical symptoms of single sulfatase deficiencies. For ten MSD patients, we determined the clinical phenotype, FGE expression, localization and stability, as well as residual FGE and sulfatase activities. A neonatal, very severe clinical phenotype resulted from a combination of two nonsense mutations leading to almost fully abrogated FGE activity, highly unstable FGE protein and nearly undetectable sulfatase activities. A late infantile mild phenotype resulted from FGE G263V leading to unstable protein but high residual FGE activity. Other missense mutations resulted in a late infantile severe phenotype because of unstable protein with low residual FGE activity. Patients with identical mutations displayed comparable clinical phenotypes. These data confirm the hypothesis that the phenotypic outcome in MSD depends on both residual FGE activity as well as protein stability. Predicting the clinical course in case of molecularly characterized mutations seems feasible, which will be helpful for genetic counseling and developing therapeutic strategies aiming at enhancement of FGE.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

SUMF1 mutations affecting stability and activity of formylglycine generating enzyme predict clinical outcome in multiple sulfatase deficiency

et al. 2011

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“…Although the pattern of axonal projections in the human brain has not been fully documented, nonhuman primate literature shows that during this period synaptic pruning continues but the wiring pattern of white matter axonal connections is relatively constant, with only limited axonal removal (6)(7)(8). However, during this time in the human brain, the white matter undergoes progressive increases in volume and changes in composition due to increases in axonal diameter and increasing myelination (9)(10)(11)(12)(13)(14). These white matter changes likely play a significant role in establishing interregional processing and neuronal synchrony in humans (15,16).…”

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confidence: 99%

White matter maturation reshapes structural connectivity in the late developing human brain

Hagmann

Sporns²,

Madan³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

624

592

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From toddler to late teenager, the macroscopic pattern of axonal projections in the human brain remains largely unchanged while undergoing dramatic functional modifications that lead to network refinement. These functional modifications are mediated by increasing myelination and changes in axonal diameter and synaptic density, as well as changes in neurochemical mediators. Here we explore the contribution of white matter maturation to the development of connectivity between ages 2 and 18 y using high b-value diffusion MRI tractography and connectivity analysis. We measured changes in connection efficacy as the inverse of the average diffusivity along a fiber tract. We observed significant refinement in specific metrics of network topology, including a significant increase in node strength and efficiency along with a decrease in clustering. Major structural modules and hubs were in place by 2 y of age, and they continued to strengthen their profile during subsequent development. Recording resting-state functional MRI from a subset of subjects, we confirmed a positive correlation between structural and functional connectivity, and in addition observed that this relationship strengthened with age. Continuously increasing integration and decreasing segregation of structural connectivity with age suggests that network refinement mediated by white matter maturation promotes increased global efficiency. In addition, the strengthening of the correlation between structural and functional connectivity with age suggests that white matter connectivity in combination with other factors, such as differential modulation of axonal diameter and myelin thickness, that are partially captured by inverse average diffusivity, play an increasingly important role in creating brain-wide coherence and synchrony.connectome | development | graph | network dynamics | tractography M ost real-world networks do not arise all at once but, guided by rules, develop through a growth process that progressively fine-tunes the configuration of nodes and edges. Thus, an important aspect in the analysis of large-scale networks is the characterization of their dynamic development and evolution. From a theoretical point of view growth rules have been shown to have a significant effect on the emergent behavior of the final large-scale structural topology. For example, the emergence of scale-free networks can be explained by a preferential attachment rule (1, 2), with important functional consequences (3). If we can measure the growth and reshaping of connectivity that occurs with maturation during the developmental process, we can begin to infer growth rules governing this complex process and examine their functional consequences. These growth rules need to be instantiated in a biological system, and therefore the functional consequences would provide hypotheses linking emergent network properties to underlying cellular and molecular mechanisms.Real-world networks rarely grow according to simple statistical models, thus necessitating empirical sampling ov...

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“…The degree of maturation and its deviation from a normal course in clinical practice are determined by visual inspection of MR images and a comparison with milestones revealed on MR imaging, such as the consecutive myelinization of certain brain structures. 1 The monitoring of quantitative MR imaging parameters allows a more objective estimation of normal or pathologic brain development as a useful adjunct to this method. [2][3][4][5][6] Recent data suggest that brain maturation still persists during adolescence.…”

mentioning

confidence: 99%

Evidence of Rapid Ongoing Brain Development Beyond 2 Years of Age Detected by Fiber Tracking

Ding

Sun²,

Braaß³

et al. 2008

AJNR Am J Neuroradiol

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Magnetic Resonance of Myelin, Myelination, and Myelin Disorders

Cited by 177 publications

References 0 publications

SUMF1 mutations affecting stability and activity of formylglycine generating enzyme predict clinical outcome in multiple sulfatase deficiency

SUMF1 mutations affecting stability and activity of formylglycine generating enzyme predict clinical outcome in multiple sulfatase deficiency

White matter maturation reshapes structural connectivity in the late developing human brain

Evidence of Rapid Ongoing Brain Development Beyond 2 Years of Age Detected by Fiber Tracking

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