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 ± 8.2 vs 24.4 ± 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 ± 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.

Cerebral Mitochondrial Microangiopathy Leads to Leukoencephalopathy in Mitochondrial Neurogastrointestinal Encephalopathy

BACKGROUND AND PURPOSE

Mitochondrial neurogastrointestinal encephalopathy is a rare disorder due to recessive mutations in the thymidine phosphorylase gene, encoding thymidine phosphorylase protein required for mitochondrial DNA replication. Clinical manifestations include gastrointestinal dysmotility and diffuse asymptomatic leukoencephalopathy. This study aimed to elucidate the mechanisms underlying brain leukoencephalopathy in patients with mitochondrial neurogastrointestinal encephalopathy by correlating multimodal neuroradiologic features to postmortem pathology.

MATERIALS AND METHODS

Seven patients underwent brain MR imaging, including single-voxel proton MR spectroscopy and diffusion imaging. Absolute concentrations of metabolites calculated by acquiring unsuppressed water spectra at multiple TEs, along with diffusion metrics based on the tensor model, were compared with those of healthy controls using unpaired t tests in multiple white matters regions. Brain postmortem histologic, immunohistochemical, and molecular analyses were performed in 1 patient.

RESULTS

All patients showed bilateral and nearly symmetric cerebral white matter hyperintensities on T2-weighted images, extending to the cerebellar white matter and brain stem in 4. White matter, N-acetylaspartate, creatine, and choline concentrations were significantly reduced compared with those in controls, with a prominent increase in the radial water diffusivity component. At postmortem examination, severe fibrosis of brain vessel smooth muscle was evident, along with mitochondrial DNA replication depletion in brain and vascular smooth-muscle and endothelial cells, without neuronal loss, myelin damage, or gliosis. Prominent periependymal cytochrome C oxidase deficiency was also observed.

CONCLUSIONS

Vascular functional and histologic alterations account for leukoencephalopathy in mitochondrial neurogastrointestinal encephalopathy. Thymidine toxicity and mitochondrial DNA replication depletion may induce microangiopathy and blood-brain-barrier dysfunction, leading to increased water content in the white matter. Periependymal cytochrome C oxidase deficiency could explain prominent periventricular impairment.

Pregnancy in CADASIL

OBJECTIVES

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebral small vessel disease caused by NOTCH3 gene mutations. CADASIL women are frequently considered at high risk of systemic vascular events during pregnancy and often prescribed with antithrombotic drugs. This decision is not evidence-based considering the lack of data about pregnancy outcome in CADASIL. We describe our experience on pregnancy in CADASIL patients.

MATERIALS AND METHODS

We reviewed records of 50 CADASIL females followed in our center, and we collected prospective information in six patients for a total of 93 pregnancies.

RESULTS

No woman had the disease onset or suffered from cerebral vascular ischemic events during pregnancy. Sixteen miscarriages (17.2%) were recorded. There were 72 vaginal births, and five cesarean sections. Considering the six patients followed prospectively (for a total of eight pregnancies), data on fetal growth and newborns weight were in line with those from the general population. Considering gestational complications, we recorded mild proteinuria without hypertension in one patient and hyperinsulinemia and pre-eclampsia in another affected by a known nephropathy. Antithrombotic drugs were used in three patients, in one for an unrelated coexisting prothrombotic condition.

CONCLUSIONS

CADASIL does not seem to be associated with an unfavorable outcome of pregnancy either for women and fetuses. Patients and treating physicians should be reassured that pregnancy can be safely initiated in CADASIL, as there is no evidence to support a specific preventive antithrombotic treatment during pregnancy in CADASIL. Larger studies are needed to definitively confirm these conclusions.

Clinical, familial, and neuroimaging features of CADASIL-like patients

OBJECTIVES

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small vessel disease caused by NOTCH3 mutations. There are no clinical and neuroimaging findings pathognomonic of the disease. The aim of this paper was to provide a description of a group of NOTCH3-negative patients with a phenotype closely resembling that of CADASIL.

MATERIALS AND METHODS

We performed NOTCH3 analysis (exons 2-23) in 117 probands because of a clinician's suspicion of CADASIL. The CADASIL scale, a recently developed tool that allows to better select patients for NOTCH3 analysis, was retrospectively applied to NOTCH3-negative patients; the patient subgroup that scored higher than the screening cutoff for CADASIL was defined as CADASIL-like.

RESULTS

Thirty-four CADASIL-like patients (mean age at onset 57.8 years [52.1-63.4], 50% males) were identified. Compared with 25 patients with CADASIL for clinical, familial, and neuroimaging features, only the following variables were significantly (α level <0.05) different in frequency between patients with CADASIL and CADASIL-like patients: a positive family history for stroke at age ≤ 60 years, more frequent in patients with CADASIL, and hypertension, more frequent in CADASIL-like patients.

CONCLUSIONS

Our experience highlights the growing number of patients presenting with a high suspicion of a cerebral small vessel disease with an autosomal dominant pattern of inheritance and a phenotype closely similar to that of CADASIL but without NOTCH3 mutations. This group remains to be characterized from the genetic point of view. The role of other genes or NOTCH3 alterations on exons other than 2-23 or introns has to be further assessed.

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.

Influence of vascular risk factors and neuropsychological profile on functional performances in CADASIL: results from the MIcrovascular LEukoencephalopathy Study (MILES)

BACKGROUND AND PURPOSE

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebral small vessel disease that may lead to disability and whose phenotype modulators are still unknown.

METHODS

In the MIcrovascular LEukoencephalopathy Study (MILES), we assessed the influence of vascular risk factors and the effect of different cognitive domains (memory, psychomotor speed and executive functions) performances on functional abilities in CADASIL in comparison with age-related leukoencephalopathy (ARL).

RESULTS

We evaluated 51 CADASIL patients (mean age 50.3 ± 13.8 years, 47.1% males) and 68 ARL patients (70.6 ± 7.4 years, 58.8% males). Considering vascular risk factors, after adjustment for age, CADASIL patients had higher mean BMI values than ARL patients. Stroke history frequency was similar in the two groups. After adjustment for age, more CADASIL patients were disabled (impaired on ≥ 2 items of the Instrumental Activities of Daily Living scale) in comparison with ARL patients, and CADASIL patients had worse functional performances evaluated with the Disability Assessment for Dementia (DAD) scale. In CADASIL patients, hypertension was related to both DAD score and disability. The cognitive profile of CADASIL and ARL patients was similar, but on a stepwise linear regression analysis functional performances were mainly associated with the memory index (β = -0.418, P < 0.003) in CADASIL patients and the executive function index (β = -0.321, P = 0.028) in ARL.

CONCLUSIONS

This study suggests that hypertension may contribute to functional impairment in CADASIL and that memory impairment has a large influence on functional decline in contrast with that observed in a sample of subjects with ARL.

Polyneuropathy in cerebrotendinous xanthomatosis and response to treatment with chenodeoxycholic acid

Polyneuropathy has been reported in cerebrotendinous xanthomatosis (CTX), although its nature and possible association with certain genotypes and phenotypes are unclear. The effect of chronic administration of chenodeoxycholic acid (CDCA) on peripheral nerve conduction parameters is still debated. We report clinical, laboratory, and electrophysiological findings in 35 CTX patients. Twenty-six subjects (74.2 %) showed peripheral nerve abnormalities. Polyneuropathy was predominantly axonal (76.9 % of patients) and generally mild. No correlation was found between its presence and clinical or biochemical data. In polyneuropathic patients, CDCA treatment improved electrophysiological conduction parameters, irrespective of the duration of therapy. Improvement mainly concerned nerve conduction velocities, whereas most nerve amplitudes remained unchanged. This means that CDCA treatment did not influence the number of axons activated by maximum electrical stimulation but increased the conduction of the still-excitable fibers. Our findings may suggest that CDCA treatment promotes myelin synthesis in nerve fibers with residual unaffected axons. The effect of therapy may therefore depend largely on the extent of irreversible structural damage to axons.

GFAP mutations, age at onset, and clinical subtypes in Alexander disease

OBJECTIVE

To characterize Alexander disease (AxD) phenotypes and determine correlations with age at onset (AAO) and genetic mutation. AxD is an astrogliopathy usually characterized on MRI by leukodystrophy and caused by glial fibrillary acidic protein (GFAP) mutations.

METHODS

We present 30 new cases of AxD and reviewed 185 previously reported cases. We conducted Wilcoxon rank sum tests to identify variables scaling with AAO, survival analysis to identify predictors of mortality, and χ(2) tests to assess the effects of common GFAP mutations. Finally, we performed latent class analysis (LCA) to statistically define AxD subtypes.

RESULTS

LCA identified 2 classes of AxD. Type I is characterized by early onset, seizures, macrocephaly, motor delay, encephalopathy, failure to thrive, paroxysmal deterioration, and typical MRI features. Type II is characterized by later onset, autonomic dysfunction, ocular movement abnormalities, bulbar symptoms, and atypical MRI features. Survival analysis predicted a nearly 2-fold increase in mortality among patients with type I AxD relative to those with type II. R79 and R239 GFAP mutations were most common (16.6% and 20.3% of all cases, respectively). These common mutations predicted distinct clinical outcomes, with R239 predicting the most aggressive course.

CONCLUSIONS

AAO and the GFAP mutation site are important clinical predictors in AxD, with clear correlations to defined patterns of phenotypic expression. We propose revised AxD subtypes, type I and type II, based on analysis of statistically defined patient groups.

Four novel CYP27A1 mutations in seven Italian patients with CTX

BACKGROUND AND PURPOSE

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disease, because of sterol 27-hydroxylase deficiency. Clinical manifestations of CTX are tendon xanthomas, juvenile cataracts, osteoporosis, diarrhoea and multiple progressive neurological dysfunctions. More than 300 patients with CTX have been reported to date worldwide and about fifty different mutations identified in CYP27A1 gene. This study describes the clinical and laboratory findings of seven new patients.

METHODS

We report the molecular and clinical characterization of seven new Italian patients with CTX carrying four novel mutations.

RESULTS

We identified four novel mutations located in different exons, in particular in the region of exons 2-5 of the CYP27A1 gene. Phenotypical expression did not differ from classical CTX presentation except for absence of tendon xanthomas in two patients.

Clinical relevance and neurophysiological correlates of spasticity in cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is a rare neurometabolic disease due to defective activity of sterol 27-hydroxylase, with plasma and tissue cholestanol storage. Clinical phenotype is characterized by both systemic manifestations and neurological signs. Therapy with chenodeoxycholic acid (CDCA) suppresses abnormal bile acid synthesis. The purpose of the study was to assess the frequency and clinical relevance of spasticity in the CTX phenotype and to study the usefulness of transcranial magnetic stimulation (TMS) in detecting corticospinal tract damage and monitoring the effects of replacement therapy. Twenty-four CTX patients underwent clinical evaluation including general disability scores, pyramidal and cerebellar function scales, assessment of serum cholestanol and TMS. Nine patients who started CDCA therapy at baseline received clinical and neurophysiological follow up. All patients showed signs of pyramidal damage which were relevant for clinical disability in 18 out of 24 cases (75%), resulting in spastic paraparesis. TMS revealed corticospinal alterations even in subjects with mild clinical signs of corticospinal tract involvement. After CDCA treatment, serum cholestanol decreased to normal concentrations in all patients. Clinical picture was unchanged in seven out of nine cases; in two others pyramidal signs disappeared. A reduction in abnormal neurophysiological parameters was found. Spastic paraparesis is the most frequent and relevant neurological feature in CTX patients. Replacement treatment with CDCA can prevent the progression of pyramidal damage, especially if started early in the course of the disease. TMS represents a sensitive indicator of corticospinal tract dysfunction and subclinical improvements in pyramidal function after CDCA therapy.

Clinical relevance of brain volume changes in patients with cerebrotendinous xanthomatosis

OBJECTIVE

To quantify total and regional brain damage in subjects with cerebrotendinous xanthomatosis (CTX) using MR based quantitative measures.

BACKGROUND

CTX is a rare inherited disorder characterised by progressive neurological impairment. Appropriate therapy can slow disease progression. Measures of brain volume changes have been used in several neurological disorders due to their value in assessing disease outcome and monitoring patients' evolution.

METHODS

24 CTX patients underwent conventional MRI to measure total and regional brain volumes. In five CTX patients who started therapy at baseline, clinical and MRI examinations were repeated after 2 years. Clinical disability, overall cognitive performance and cerebellar function were evaluated using the modified Rankin Scale (RS), Mini Mental Status Examination (MMSE) and cerebellar functional system score (CB-FSS).

RESULTS

Measures of normalised brain, cortical and cerebellar volumes were lower in CTX patients than in healthy controls (p<0.01). Instead, there were no differences in normalised white matter volumes between the two groups (p=0.1). At regional analysis, a significant volume decrease was found in each cortical region (p<0.01 for all regions). Normalised cortical volumes correlated closely with age (r=-0.9, p<0.0001), RS (r=-0.65, p<0.001) and MMSE (r=-0.60, p<0.01). Normalised cerebellar volumes correlated closely with CB-FSS scores (r=-0.58, p<0.01). In the five CTX patients followed over time, the annual brain volume decrease was -1.1 ± 0.2%.

CONCLUSIONS

Cortical volume, rather than white matter volume, is diffusely decreased in CTX patients and correlates closely with the patient's clinical status. These data provide evidence for the presence of clinically relevant neuronal-axonal damage in the brains of CTX patients.

Four novel CYP27A1 mutations in seven Italian patients with CTX

BACKGROUND AND PURPOSE

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disease, because of sterol 27-hydroxylase deficiency. Clinical manifestations of CTX are tendon xanthomas, juvenile cataracts, osteoporosis, diarrhoea and multiple progressive neurological dysfunctions. More than 300 patients with CTX have been reported to date worldwide and about fifty different mutations identified in CYP27A1 gene. This study describes the clinical and laboratory findings of seven new patients.

METHODS

We report the molecular and clinical characterization of seven new Italian patients with CTX carrying four novel mutations.

RESULTS

We identified four novel mutations located in different exons, in particular in the region of exons 2-5 of the CYP27A1 gene. Phenotypical expression did not differ from classical CTX presentation except for absence of tendon xanthomas in two patients.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited autosomal dominant condition characterized by migrane, recurrent stroke, subcortical dementia, and pseudobulbar palsy. It begins with migraine with aura in -33% of patients. CADASIL is commonly overlooked or misdiagnosed owing to its recent identification. The pathological hallmark of angiopathy is the presence of multiple, small, deep cerebral infarcts, leucoencephalopathy, and nonatherorosclerotic, nonamyloid angiopathy involving mainly small, deep perforating cerebral arteries. Changes also are present in vascular smooth muscle cells and consist in the presence of granular osmiophilic material (GOM). The defective gene in CADASIL is Notch 3, which encodes a large transmembrane receptor. Magnetic resonance imaging shows high intensity signal lesions, often confluent, and areas of cystic degeneration of subcortical white matter and basal ganglia. Diagnostic strategies in CADASIL are matter of discussions because the electron microscopic demonstration of GOM was reported in 100% of symptomatic patients of French authors, but only in 45% of a British study. GOMs are not present in presymptomatic patients.

Structural and metabolic brain abnormalities in preclinical cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy

OBJECTIVE

To assess, by using quantitative MRI metrics, structural and metabolic brain abnormalities in subjects with preclinical cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL).

BACKGROUND

Brain MRI abnormalities have been occasionally reported in preclinical CADASIL subjects. However, very little is known as to when the brain tissue damage starts to accumulate, what brain regions are primarily involved and whether the brain damage is significant in subjects who have no overt clinical manifestations of the disease.

METHODS

Twelve subjects (mean age 40 years; range 26-55 years; males/females 6/6) with genetically proven CADASIL and no clinical signs of the disease underwent conventional MRI and proton MR spectroscopic imaging ((1)H-MRSI) to measure white matter (WM) lesion volume (LV), global and regional cerebral volumes, and WM levels of N-acetylaspartate (NAA) normalised to creatine (Cr). MR values were compared with those of 13 age- and sex-matched healthy controls.

RESULTS

All preclinical CADASIL showed WM lesions (range 0.2 to 26 cm(3)). They were mostly distributed in the frontal and parietal regions, with the highest probability in the corona radiata. On (1)H-MRSI examination, NAA/Cr values were lower in preclinical CADASIL than in HC, particularly in the corona radiata (p<0.01). Normalised brain and cortical volumes were also lower in preclinical CADASIL than in HC (p<0.01), particularly in the frontal cortex.

CONCLUSIONS

The pathological process occurring in CADASIL leads to damage of WM and neocortex much before the evidence of clinical symptoms. At this preclinical stage, this seems to take place prevalently in the frontal brain region.

CSF levels of beta-amyloid 1-42, tau and phosphorylated tau protein in CADASIL

BACKGROUND AND PURPOSE

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) can be considered a useful model of pure subcortical vascular dementia (SVD) because it occurs in young adults, unlikely to have concomitant age- and Alzheimer's disease (AD)-related pathology. In patients with CADASIL we evaluated the cerebrospinal fluid (CSF) levels of beta-amyloid 1-42 (Abeta42), total tau protein (t-tau) and phosphorylated tau protein (p-tau), which are well-accepted biomarkers of AD.

METHODS

The CSF Abeta42, t-tau and p-tau levels were determined with Innotest beta-amyloid 1-42, Innotest hTAU-Ag and Innotest Phospho-tau 181p sandwich enzyme-linked immunoassay, in 10 CADASIL patients and 17 healthy age-matched subjects. A case-control statistical analysis was carried out.

RESULTS

CSF Abeta42 levels were significantly lower in CADASIL patients than in controls, whereas CSF t-tau and p-tau levels did not differ between the two groups.

CONCLUSIONS

The pattern found in CADASIL patients is similar to that reported in those with sporadic SVD, suggesting that decreased CSF Abeta42 might be related to the subcortical vascular lesions in the white matter.

Increased QT variability in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

BACKGROUND AND PURPOSE

Although sudden death (SD) accounts for numerous cases of premature mortality in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the risk factors responsible for this dramatic event remain unclear. We sought possible differences in the QT variability index (QTVI) -- a well-known index of temporal dispersion in myocardial repolarization strongly associated with the risk of SD -- between a group of patients with CADASIL and healthy controls.

METHODS

A total of 13 patients with CADASIL and 13 healthy volunteers underwent a 5-min electrocardiogram recording to calculate the QTVI. All the patients also underwent a clinical assessment, including functional status by Rankin score, and a magnetic resonance imaging (MRI) brain scan for quantitative analysis of T2-weighted (T2-W) and T1-weighted (T1-W) lesion volume (LV).

RESULTS

Short-term QT-interval analysis showed significantly higher QTVI (P = 0.029) in patients than in controls. In patients, notwithstanding the limitations of the small sample size, QTVI also well correlated with T1-W LV (r = 0.747, P = 0.003) and T2-W LV (r = 0.731, P = 0.005).

CONCLUSION

Because patients with CADASIL have increased temporal cardiac repolarization variability as assessed by QTVI, this mechanism could underlie these patients' risk of SD. Whether this easily assessed, non-invasive marker could be used to stratify the risk of malignant ventricular arrhythmias in patients with CADASIL and, possibly, to guide their therapeutic management warrants confirmation from larger prospective studies.

Brain structural damage in Friedreich's ataxia

OBJECTIVE

Neuropathological descriptions of the brain in Friedreich's ataxia (FRDA) were obtained before availability of the current molecular genetic tests for this disease. Voxel-based morphometry (VBM) enables an unbiased whole-brain quantitative analysis of differences in gray matter (GM) and white matter (WM) volume.

METHODS

Using VBM, we assessed the brain structural damage in 22 patients with genetically confirmed FRDA and 25 healthy controls. The results were correlated with the disease duration and the severity of the patients' clinical deficits--evaluated using the International Cerebellar Ataxia Rating Scale and Inherited Ataxia Clinical Rating Scale.

RESULTS

In patients with FRDA, VBM showed a symmetrical volume loss in dorsal medulla, infero-medial portions of the cerebellar hemispheres, the rostral vermis and in the dentate region. No volume loss in cerebral hemispheres was observed. The atrophy of the cerebellum and medulla correlated with the severity of the clinical deficit and disease duration.

CONCLUSIONS

In patients with FRDA, significant GM and WM loss was observed only in the cerebellum and dorsal medulla. These structural changes correlate with the severity of the clinical deficit and disease duration.

Prominent brain axonal damage and functional reorganization in "pure" adrenomyeloneuropathy

BACKGROUND

Cerebral involvement is usually absent in pure adrenomyeloneuropathy (AMN). Recently, nonconventional MR studies have reported brain abnormalities in patients with pure AMN, providing evidence that occult cerebral involvement may occur in this disease. It remains unclear, however, whether these brain abnormalities reflect centripetal extension of spinal cord long-tract axonopathy or can be the expression of a pathologic process largely involving the brain.

METHODS

Conventional MRI and proton MR spectroscopic imaging (1H-MRSI) data of four patients with pure AMN were compared to those of four men with spinal cord injury (SCI) and 10 age-matched healthy men (HM). Resonance intensity areas of N-acetylaspartate (NAA) and choline were calculated as ratios to creatine (Cr) in voxels located in white matter (WM) regions. Functional MRI (fMRI) data during simple motor task were obtained in a separate session in three patients with AMN and three age-matched HM.

RESULTS

Conventional MRI examinations were normal in all patients. On 1H-MRSI, NAA/Cr values were lower in all WM regions of patients with AMN than in those of patients with SCI (p < 0.05) and HM (p < 0.01). In contrast, patients with SCI showed NAA/Cr values lower than HM only in the periventricular WM (p = 0.04). At fMRI, patients with AMN showed a more pronounced activation than HM in all movement-associated cortical regions contralateral to the hand moved and an exclusive voxel activation of the primary motor, somatosensory, and posterior parietal cortices ipsilateral to the hand moved.

CONCLUSIONS

CNS damage in pure adrenomyeloneuropathy is not confined exclusively to spinal cord and seems to primarily involve the brain.

Recurrent venous thrombosis including cerebral venous sinus thrombosis in a patient taking sildenafil for erectile dysfunction

Acquired or hereditary prothrombotic risk factors may lead to cerebral venous sinus thrombosis (CVST), particularly when other predisposing factors coexist. A 57-year-old man experienced right leg deep venous thrombosis, severe thrombosis of the haemorrhoid plexus and CVST over a 12-month period during which he was taking sildenafil regularly twice a week. Sildenafil is a phosphodiesterase 5 (PDE5)-inhibitor used for erectile dysfunction (ED). A slight reduction in antithrombin III and free protein S levels was demonstrated. After suspension of sildenafil and six months on oral anticoagulants, clinical improvement was obtained. Recurrent venous thrombosis, including CVST, may complicate prolonged treatment with PDE5-inhibitors in subjects at risk. Periodic monitoring of clotting factors is recommended in these subjects.

Morphometry and 1H-MR spectroscopy of the brain stem and cerebellum in three patients with fragile X-associated tremor/ataxia syndrome

SUMMARY

Morphometry and spectroscopy were performed in 3 patients with fragile X-associated tremor/ataxia syndrome (FXTAS). The brain stem and cerebellum were atrophic and satisfied criteria for olivopontocerebellar atrophy in 2 patients. However, the vermis was relatively spared and the basis pontis maintained its oval shape. The only spectroscopic abnormality was a decrease of the pontine N-acetylaspartate/creatine ratio in 1 patient. Atrophy and metabolic changes in FXTAS differ to some extent from those of olivopontocerebellar atrophy.

Clinical and molecular diagnosis of cerebrotendinous xanthomatosis with a review of the mutations in the CYP27A1 gene

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disease due to defective activity of the mitochondrial enzyme sterol 27-hydroxylase. In 1991, sterol 27-hydroxylase gene (CYP27A1) was localised on the long arm of chromosome 2 [1]. Clinical characteristics of CTX are diarrhoea, cataracts, tendon xanthomas and neurological manifestations including dementia, psychiatric disturbances, pyramidal and/or cerebellar signs, and seizures. More than 300 patients with CTX have been reported to date worldwide and about 50 different mutations identified in the CYP27A1 gene. Almost all mutations lead to the absence or inactive form of the sterol 27-hydroxylase. In this review, according with the aims of this section of the journal, we describe the different pathogenetic mutations in the CYP27A1 gene and the main clinical and pathogenetic aspects that may help clinical neurologists in the diagnosis of CTX.

Peripheral neuropathy in vanishing white matter disease with a novel EIF2B5 mutation

The authors describe an infant with vanishing white matter disease with demyelinating peripheral neuropathy. Sequence analysis of EIF2B5 gene showed that the patient was a double heterozygote, with novel missense mutation CGA-->CAA in codon 269 of exon 6, resulting in the replacement of an arginine residue with glutamine.

Clinical and molecular diagnosis of cerebrotendinous xanthomatosis with a review of the mutations in the CYP27A1 gene

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disease due to defective activity of the mitochondrial enzyme sterol 27-hydroxylase. In 1991, sterol 27-hydroxylase gene (CYP27A1) was localised on the long arm of chromosome 2 [1]. Clinical characteristics of CTX are diarrhoea, cataracts, tendon xanthomas and neurological manifestations including dementia, psychiatric disturbances, pyramidal and/or cerebellar signs, and seizures. More than 300 patients with CTX have been reported to date worldwide and about 50 different mutations identified in the CYP27A1 gene. Almost all mutations lead to the absence or inactive form of the sterol 27-hydroxylase. In this review, according with the aims of this section of the journal, we describe the different pathogenetic mutations in the CYP27A1 gene and the main clinical and pathogenetic aspects that may help clinical neurologists in the diagnosis of CTX.

Auditory neuropathy in a patient with mitochondrial myopathy and multiple mtDNA deletions

Auditory neuropathy (AN) is a hearing disorder characterized by the absence or severe distortion of the auditory brainstem responses, in the presence of preserved otoacoustic emissions. This peculiar combination suggests the presence of a defect impinging upon the functional complex formed by inner hair cells, the primary afferents (spiral ganglion neurones) and the first order synapses between hair cells and the cochlear nerve. Typically, AN patients show a severe speech perception impairment, which appears reduced out of proportion to pure tone threshold, but the clinical presentation of AN is quite complex.

Hearing loss is a common symptom associated with mitochondrial diseases; however, AN has only rarely been reported in these disorders.

Here we report a rare association, the first case observed in Italy, in a patient with autosomal recessive mitochondrial myopathy and mitochondrial DNA multiple deletions, and a hearing deficit with the audiological and electrophysiological features of AN.

Cerebellar arteriovenous malformation and vertebral artery aneurysm in a CADASIL patient

The presence of large vessels malformations has not been reported in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). We describe a CADASIL patient in whom a brain cerebellar arteriovenous malformation was revealed by magnetic resonance (MR) imaging. An MR angiogram documented also an aneurysm along the right intracranial vertebral artery at the junction with the posterior-inferior cerebellar artery. The aneurysm was successfully treated by means of endovascular coil embolization. No neurological complication occurred in our patient during the angiographic procedure. In this case, in addition to an incidental coexistence of CADASIL and large vessels abnormalities, a causal role of the Notch pathway alteration could be hypothesized. Dysregulation of the Notch pathway is linked to several human diseases besides CADASIL. In one of these (the Alagille syndrome) intracranial aneurysms are reported. This hypothesis contrasts however with the absence of similar reports in other CADASIL cases and needs corroboration in large series.

Typical pathological changes of CADASIL in the optic nerve

Visual impairment due to retinal and optic nerve changes in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is more common than previously thought. Deposits of granular osmiophilic material (GOM) have been shown in the wall of retinal arterioles, though retinal infarcts and vascular occlusions have never been reported. Ischaemic optic neuropathy, on the other hand, has been reported in one case of CADASIL but no pathology reports of the optic nerve have been published. Here we report optic nerve morphological findings in the autopsy material of a 41-year-old woman with genetically assessed CADASIL. Longitudinal and transverse sections of optic nerves were examined. Classical histological methods (haematoxylin-eosin and Nissl) were performed. Diffuse pallor of myelin and rarefaction of optic nerve fibres were observed. Classical GOM was evident in the tunica media of vessels in the meninges and white matter. Arteriole lumina were slightly narrowed. In conclusion, the typical pathological changes of CADASIL occur in the optic nerve and may contribute to impairment of visual function in CADASIL.

Lung involvement in Niemann-Pick disease type C1: improvement with bronchoalveolar lavage

Progressive lung infiltration is a major cause of death in Niemann-Pick disease type A and B (NPA, NPB) and in the recently defined type C2. In type C1 (NPC1), the main manifestations are neurological. We report a patient with a classic, neurological, late infantile form of NPC1 disease, carrying the mutation P474L and the variant I642M in the NPC1 gene, who suffered recurrent respiratory manifestations. Bronchoalveolar lavage of a lung segment due to deteriorating respiratory condition revealed many foamy macrophages and was followed by an improvement in symptoms. Pneumopathy may therefore be considered a feature of NPC1 disease for which a partial bronchoalveolar lavage could be a useful treatment.