Defining and Categorizing Leukoencephalopathies of Unknown Origin: MR Imaging Approach

Abstract

Establishing these seven categories helps in the interpretation of individual studies by demonstrating features that the patient has in common with other patients, and it may facilitate further research on homogeneous subgroups of patients and allow pooling of data across multiple centers.

Hypomyelination and Congenital Cataract: Neuroimaging Features of a Novel Inherited White Matter Disorder

“…6 The former mechanism underlies Pelizaeus-Merzbacher disease, which is caused by a defect of the proteolipid protein, a major constituent of the myelin proteolipidic structure; on the other hand, the latter phenomena determine early-onset lysosomal storage disorders, Salla disease, Cockayne syndrome, and trichothiodystrophy. 1 In this series, hypomyelination was widespread in the supratentorial brain, with the sole exception of partial subcortical sparing in 2 patients; conversely, the cerebellum was less markedly involved, with completely normal findings in 3 patients and subcortical white matter preservation in all patients.…”

“…MR imaging evidence of hypomyelination is common in children, though its cause often remains undetermined. 1 Hypomyelination may be related to either primary disturbance of myelin formation or to neuronal, oligodendrocytic, or astrocytic dysfunction leading to secondary failure of myelination. 6 The former mechanism underlies Pelizaeus-Merzbacher disease, which is caused by a defect of the proteolipid protein, a major constituent of the myelin proteolipidic structure; on the other hand, the latter phenomena determine early-onset lysosomal storage disorders, Salla disease, Cockayne syndrome, and trichothiodystrophy.…”

“…Studies have shown that a specific diagnosis remains undetermined in as many as 50% of children with a leukoencephalopathy. 1 However, genetic research has greatly contributed to the understanding of the etiologic background of several white matter disorders in the last decade, providing new insight into the disease inheritance pattern and risk of familial recurrence as well as offering a method for prenatal diagnosis. 2 The term hypomyelination indicates reduced or absent myelin deposition that may involve the central nervous system, the peripheral nervous system, or both.…”

“…3 However, hypomyelinating disorders still represent the largest single category among unclassified leukoencephalopathies. 1 Hypomyelination and congenital cataract (HCC) (Online Mendelian Inheritance in Man, No. 610532) is a recently described autosomal recessive white matter disorder characterized by central and peripheral hypomyelination, slowly progressive neurologic impairment, and congenital cataract, caused by a deficiency of a novel membrane protein, hyccin, encoded by the DRCTNNB1A gene located on chromosome 7p15.3.…”

RMND1-Related Leukoencephalopathy With Temporal Lobe Cysts and Hearing Loss—Another Mendelian Mimicker of Congenital Cytomegalovirus Infection

“…MRIs were scored according to a standard protocol for extent and localization of white matter abnormalities as well as cystic changes in the temporal lobe or elsewhere (van der Knaap et al, 1999). Descriptive analysis of clinical and MRI features was performed due to the small size of these cohorts.…”