Peak width of skeletonized mean diffusivity (PSMD) as marker of widespread white matter tissue damage in multiple sclerosis.

BACKGROUND: Peak width of skeletonized mean diffusivity (PSMD) is a novel and fully automated, MRI biomarker, which has shown clinical relevance in cerebral small vessel diseases (SVD). We aimed here to assess PSMD levels across the brain of patients with multiple sclerosis (MS), in comparison to normal controls (NC) and patients with CADASIL, a genetically defined form of severe SVD. METHODS: We assessed PSMD in relapsing-remitting (RR) MS patients (n = 47) in comparison to age-matched CADASIL patients (n = 25) and NC (n = 28). Diffusion Tensor Imaging data were acquired on 1.5T MR clinical scanner to automatically compute PSMD through "skeletonization" of WM tracts and diffusion histograms. RESULTS: RRMS had lower WM lesion volume (LV) than CADASIL (8.6 ±â€¯8.2 vs 24.4 ±â€¯17.4 cm3, p < 0.001). After correction for LV, PSMD values in MS were higher than in CADASIL patients (adjusted mean values: 4.5 vs 3.9 × 10-4 mm2/s, p = 0.03) and in both patient groups were higher than in NC (2.8 ±â€¯0.3 × 10-4 mm2/s, p < 0.001). PSMD values correlated with LV in both patient groups (r = 0.8, p < 0.001 in MS; r = 0.6, p = 0.002 in CADASIL). CONCLUSIONS: In both patient groups, PSMD was higher than in NC and closely correlated with LV, suggesting sensitivity in assessing brain tissue damage in these disorders. In MS patients, PSMD levels were higher than in CADASIL patients, despite the lower LV. This might be related to more severe normal-appearing WM abnormalities occurring in the MS brains. This novel, fully automated, MRI metric may represent a useful marker for a robust quantification of the diffuse WM tissue damage in MS.

AARS2-related ovarioleukodystrophy: Clinical and neuroimaging features of three new cases.

INTRODUCTION: Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP), previously known as hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) or pigmentary orthochromatic leukodystrophy (POLD), is the most frequent non-vascular adult-onset leukoencephalopathy. It is caused by autosomal dominant mutations in CSF1R gene. Recently, also autosomal recessive mutations in AARS2 gene were found to be the cause of an adult-onset leukodystrophy with axonal spheroids. Our aim was to achieve a genetic diagnosis in a cohort of CSF1R-negative patients, performing a sequence analysis of AARS2 gene. MATERIAL AND METHODS: AARS2 sequencing was performed in 38 CSF1R-negative patients with clinical and magnetic resonance imaging (MRI) findings of adult-onset leukoencephalopathy. RESULTS: Three patients carrying AARS2 compound heterozygous mutations have been found. All patients were female with ovarian failure and leukoencephalopathy. In 2 patients, MRI findings were consistent with previous reports while the third patient showed focal white matter (WM) lesions in the centrum semiovale and the corpus callosum in the absence of extensive involvement and rarefaction of the WM. MRI spectroscopy showed the presence of increased lactate in 2 patients, thus linking AARS2-related leukoencephalopathy with other mitochondrial leukoencephalopathies with high levels of cerebral lactate. CONCLUSION: We recommend screening for mutations in AARS2 gene in CSF1R-negative patients, also in the absence of a clear family history and peculiar MRI findings. Our results also suggest that findings of conventional MRI and MR spectroscopy may be useful in prompting the genetic screening.

Adult-Onset Genetic Leukoencephalopathies. Focus on the More Recently Defined Forms.

Inherited white matter (WM) disorders include a heterogenous group of disorders affecting brain white matter and associated with myelin, axonal and glial cells or vascular pathology. Often a wide range of overlapping neurological manifestations possibly associated with variable systemic involvement are found in these disorders making clinical diagnosis challenging. Advances in molecular genetics enabled the identification of the responsible genes of an increasing number of previously undefined forms. This review focuses on genetic leukoencephalopathies with exclusive adulthood presentation, most of which have an autosomal dominant inheritance. The most common forms are related to vascular pathology, such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), COL4A1-related leukoencephalopathy, retinal vasculopathy with cerebral leukodystrophy (RVCL), and polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL). Also cerebroretinal microangiopathy with cysts and calcifications (CRMCC), which presents a prevalent infantile onset, will be detailed because of the vascular based myelin damage and the recent genetic characterization. Other adult onset (AO) leukoencephalopathies, such as the recently genetically defined hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS), adult-onset autosomal dominant leukodystrophy (ADLD) due to LMNB1 duplication, adult polyglucosan body disease (APBD), and fragile X-associated tremor/ataxia syndrome (FXTAS) will be detailed shortly. Short notes on the clinical and MRI features of late onset variants of the classical infantile-onset leukodystrophies mostly related to metabolic disorders will also be given. Finally, palliative, curative and experimental treatment options are here summarized.

Tarlov cysts: clinical evaluation of an italian cohort of patients.

Tarlov cyst syndrome is a rare, often asymptomatic disorder, characterised by isolated or multiple nerve-root cysts, usually occurring in the sacral spine, near the dorsal root ganglion, between the perineurium and endoneurium. The cysts may cause lower back pain, sacral radiculopathy, dyspareunia and urinary incontinence. There is little data in the literature on the relationship between Tarlov cysts and symptoms. Here, we report further details on the clinical impact of Tarlov cysts and investigate their pathogenesis and role as a cause of lumbosacral symptoms. We examined 157 patients with MRI evidence of symptomatic Tarlov cysts. Patients underwent complete neurological examination and were scored by the Hamilton Depression Rating Scale and the Visual Analogue Scale. Complete lower limb electromyography was performed in 32 patients. Clinical picture was correlated with size and number of cysts detected by MRI. Family history was recorded for signs of genetic inheritance. Almost all patients suffered perineal or lower back pain; 34 complained of sphincter and 46 of sexual disorders. Hamilton scores were abnormal, and family history was positive in a few cases. The scanty literature on Tarlov cysts mainly regards therapy by a neurosurgical approach. Our results provide new data on clinical impact and possible pathogenetic mechanisms.

Ataxia with vitamin E deficiency: update of molecular diagnosis.

Ataxia with vitamin E deficiency (AVED) is a rare autosomal recessive neurodegenerative disease, due to mutations in TTPA gene (Arita et al. in Biochem J 306(Pt. 2):437-443, 1995; Hentati et al. in Ann Neurol 39:295-300, 1996), which encodes for alpha-TTP, a cytosolic liver protein that is presumed to function in the intracellular transport of alpha-tocopherol. This disease is characterized clinically by symptoms with often striking resemblance to those of Friedreich ataxia. The neurological symptoms include ataxia, dysarthria, hyporeflexia, and decreased vibration sense, sometimes associated with cardiomyopathy and retinitis pigmentosa (Mariotti et al. in Neurol Sci 25:130-137, 2004). Vitamin E supplementation improves symptoms and prevents disease progress (Doria-Lamba et al. in Eur J Pediatr 165(7):494-495, 2006). Over 20 mutations have been identified in patients with AVED. In the present paper we summarize the recent findings on molecular genetic of this disease including the list of the known mutations.