MR spectroscopy in 18q(-) syndrome suggesting other than hypomyelination

Interstitial de novo 18q22.3q23 deletion: clinical, neuroradiological and molecular characterization of a new case and review of the literature

Background

Deletions of the long arm of chromosome 18 cause a common autosomal syndrome clinically characterized by a protean clinical phenotype.

Case presentation

We report on a 16-month-old male infant affected by fever attacks apparently unrelated with any infectious or inflammatory symptoms, growth retardation, bilateral vertical talus, congenital aural atresia, dysmorphisms, mild psychomotor delay, and peculiar neuroradiological features. Array-CGH analysis revealed one of the smallest 18q22.3q23 interstitial deletions involving five genes: TSHZ1, ZNF516, ZNF236, MBP, and GALR1.

Conclusions

Herein we focus on previously unreported heralding symptoms and neuroradiological abnormalities which enlarge the spectrum of 18q deletion syndrome demonstrating that a small deletion can determine a complex phenotype.

Reprint of "Hypomyelinating disorders: An MRI approach

In recent years, the concept of hypomyelinating disorders has been proposed as a group of disorders with varying systemic manifestations that are identified by MR findings of absence or near absence of the T2 hypointensity that develops in white matter as a result of myelination. Initially proposed as a separate group because they were the largest single category of undiagnosed leukodystrophies, their separation as a distinct group that can be recognized by looking for a specific MRI feature has resulted in a marked increase in their diagnosis and a better understanding of the different causes of hypomyelination. This review will discuss the clinical presentations, imaging findings on standard MRI, and new MRI-related techniques that allow a better understanding of these disorders and proposed methods for quantifying the myelination as a potential means of assessing disease course and the effects of proposed treatments. Disorders with hypomyelination of white matter, or hypomyelinating disorders (HMDs), represent the single largest category among undiagnosed genetic leukoencephalopathies (Schiffmann and van der Knaap, 2009; Steenweg et al., 2010). This group of inborn errors of metabolism is characterized by a magnetic resonance imaging (MRI) appearance of reduced or absent myelin development: delay in the development of T2 hypointensity and, often, T1 hyperintensity in the white matter of the brain. The concept of hypomyelination was first conceptualized by (Schiffmann and van der Knaap, 2009; Steenweg et al., 2010; Schiffmann et al., 1994) in a series of papers that showed that these MRI characteristics were easily recognized, were different from the MRI characteristics of dysmyelinating and demyelinating disorders, and that the combination of these imaging findings with specific other clinical and imaging features could be used to make diagnoses with some confidence. In this manuscript, we will discuss the physiologic and genetic bases of hypomyelinating disorders, as well as their classification, clinical manifestations and imaging characteristics.

Hypomyelinating disorders: An MRI approach

In recent years, the concept of hypomyelinating disorders has been proposed as a group of disorders with varying systemic manifestations that are identified by MR findings of absence or near absence of the T2 hypointensity that develops in white matter as a result of myelination. Initially proposed as a separate group because they were the largest single category of undiagnosed leukodystrophies, their separation as a distinct group that can be recognized by looking for a specific MRI feature has resulted in a marked increase in their diagnosis and a better understanding of the different causes of hypomyelination. This review will discuss the clinical presentations, imaging findings on standard MRI, and new MRI-related techniques that allow a better understanding of these disorders and proposed methods for quantifying the myelination as a potential means of assessing disease course and the effects of proposed treatments. Disorders with hypomyelination of white matter, or hypomyelinating disorders (HMDs), represent the single largest category among undiagnosed genetic leukoencephalopathies (Schiffmann and van der Knaap, 2009; Steenweg et al., 2010). This group of inborn errors of metabolism is characterized by a magnetic resonance imaging (MRI) appearance of reduced or absent myelin development: delay in the development of T2 hypointensity and, often, T1 hyperintensity in the white matter of the brain. The concept of hypomyelination was first conceptualized by (Schiffmann and van der Knaap, 2009; Steenweg et al., 2010; Schiffmann et al., 1994) in a series of papers that showed that these MRI characteristics were easily recognized, were different from the MRI characteristics of dysmyelinating and demyelinating disorders, and that the combination of these imaging findings with specific other clinical and imaging features could be used to make diagnoses with some confidence. In this manuscript, we will discuss the physiologic and genetic bases of hypomyelinating disorders, as well as their classification, clinical manifestations and imaging characteristics.