Mitra Assadi

Long-Term Follow-Up After Gene Therapy for Canavan Disease

Gene therapy for Canavan disease results in a decrease in pathologically elevated N-acetyl-aspartate concentrations in the brain and long-term clinical stabilization. Gene Therapy for Canavan Disease Canavan disease is a fatal childhood neurodegenerative disorder for which there is no effective treatment. It is caused by a defect in a single gene (ASPA) that results in a deleterious buildup of N-acetyl-aspartate in the brain. This process starts at birth and is accompanied by a failure to form and maintain myelin, the protective sheath surrounding nerves. As a brain-specific disorder with simple Mendelian inheritance, Canavan disease represents an excellent target for enzyme replacement using gene therapy. Leone et al. now report the long-term results of gene therapy in 13 Canavan disease patients using adeno-associated viral vector delivery of the ASPA gene. The investigators found that gene therapy was safe and led to a decrease in N-acetyl-aspartate in the brain, together with decreased seizure frequency and clinical stabilization. Clinical stabilization was greatest in the youngest patients. Early detection and treatment with gene therapy–mediated enzyme replacement in the neonatal period may offer the best opportunity for a reduction in symptoms and long-term stabilization in patients with Canavan disease. Canavan disease is a hereditary leukodystrophy caused by mutations in the aspartoacylase gene (ASPA), leading to loss of enzyme activity and increased concentrations of the substrate N-acetyl-aspartate (NAA) in the brain. Accumulation of NAA results in spongiform degeneration of white matter and severe impairment of psychomotor development. The goal of this prospective cohort study was to assess long-term safety and preliminary efficacy measures after gene therapy with an adeno-associated viral vector carrying the ASPA gene (AAV2-ASPA). Using noninvasive magnetic resonance imaging and standardized clinical rating scales, we observed Canavan disease in 28 patients, with a subset of 13 patients being treated with AAV2-ASPA. Each patient received 9 × 1011 vector genomes via intraparenchymal delivery at six brain infusion sites. Safety data collected over a minimum 5-year follow-up period showed a lack of long-term adverse events related to the AAV2 vector. Posttreatment effects were analyzed using a generalized linear mixed model, which showed changes in predefined surrogate markers of disease progression and clinical assessment subscores. AAV2-ASPA gene therapy resulted in a decrease in elevated NAA in the brain and slowed progression of brain atrophy, with some improvement in seizure frequency and with stabilization of overall clinical status.

Mild-onset presentation of Canavan's disease associated with novel G212A point mutation in aspartoacylase gene.

We describe two sisters with a mild‐onset variant of Canavans disease who presented at age 50 and 19 months with developmental delay but without macrocephaly, hypotonia, spasticity, or seizures. Remarkably, both patients had age‐appropriate head control, gross motor development, and muscle tone. There were very mild deficits in fine motor skills, coordination, and gait. Both sisters had a history of strabismus, but otherwise vision was normal. The older child showed evidence of mild cognitive and social impairment, whereas language and behavior were normal for age in the infant. Both patients were found to be compound heterozygotes for C914A (A305E) and G212A (R71H) mutations in ASPA. Like all other known ASPA mutations, this previously unknown G212A mutation appears to have low absolute enzyme activity. Nevertheless, it is associated in these patients with an extremely benign phenotype that is highly atypical of Canavans disease. Biochemical and clinical data were evaluated using a generalized linear mixed model generated from 25 other subjects with Canavans disease. There were statistically significant differences in brain chemistry and clinical evaluations, supporting a distinct variant of Canavans disease. Future studies of ASPA enzyme structure and gene regulation in these subjects could lead to a better understanding of Canavans pathophysiology and improvements in ASPA gene therapy Ann Neurol 2006;59:428–431

Lithium citrate reduces excessive intra-cerebral N-acetyl aspartate in Canavan disease.

Our group has previously reported the first clinical application of lithium in a child affected by Canavan disease. In this study, we aimed to assess the effects of lithium on N-acetyl aspartate (NAA) as well as other end points in a larger cohort. Six patients with clinical, laboratory and genetic confirmation of Canavan disease were recruited and underwent treatment with lithium. The battery of safety and efficacy testing performed before and after sixty days of treatment included Gross Motor Function Testing (GMFM), Magnetic Resonance Imaging (MRI) Proton Magnetic Spectroscopy (H-MRS) as well as blood work. The medication was safe without any clinical or laboratory evidence for toxicity. Parental reports indicated improvement in alertness and social interactions. GMFM did not show statistically significant improvement in motor development. H-MRS documented an overall drop in NAA which was statistically significant in the basal ganglia. T1 measurements recorded on MRI studies suggested a mild improvement in myelination in the frontal white matter after treatment. Diffusion Tensor Imaging was available in two patients and suggested micro-structural improvement in the corpus callosum. The results suggest that lithium administration may be beneficial in patients with Canavan disease.

Treatment of spinocerebellar ataxia with buspirone

Preliminary data suggest potential benefit of 5-HT receptor agonists in the treatment of ataxias. We studied the effects of buspirone in a cohort of twenty patients with spinocerebellar ataxia (SCA). Twenty patients were treated in this double-blind, placebo controlled, cross-over trial with either buspirone HCl 30 mg twice daily or placebo for 3 months. Buspirone was not shown to be superior to placebo in the treatment of patients with SCA.

Validating an Ataxia Functional Composite Scale in spinocerebellar ataxia

The Ataxia Functional Composite Scale (AFCS) may provide a sensitive and reproducible assessment of treatment responses in studies of the spinocerebellar ataxias (SCA). We previously assessed the effects of buspirone in a cohort of patients with SCA via the International Cooperative Ataxia Rating Scale (ICARS). At each assessment period, AFCS scores were also obtained. A strong correlation of AFCS with ICARS scores was demonstrated at all assessment periods. This study supports the validity of the AFCS as a useful assessment of ataxia in this population.

Serial 1H-MRS in GM2 gangliosidoses.

GM2 gangliosidoses are a group of neuronal storage disorders caused by deficiency in the lysosomal enzyme hexosaminidase A. Clinically, the disease is marked by a relentless encephalopathy. Proton magnetic resonance spectroscopy (1H-MRS) provides in-vivo measurement of various brain metabolites including N-acetyl aspartate+N-acetyl aspartate glutamate (NAA), myo-inositol (mI), choline (Cho) and creatine (Cr). The NAA represents neuronal integrity while elevation in the mI reflects abnormal inflammation and gliosis in the brain tissue. An elevation in the Cho levels suggest cell membrane breakdown and demyelination. We report the clinical and laboratory data in two patients with GM2 gangliosidoses. Serial 1H-MRS evaluations were performed to drive metabolite ratios of NAA/Cr, mI/Cr and Cho/Cr. We acquired the data from four regions of interest (ROI) according to a standard protocol. The results documented a progressive elevation in mI/Cr in all four ROI in patient one and only one ROI (occipital gray matter) in patient 2. We also documented a decline in the NAA/Cr ratios in both cases in most ROI. These results were compared to six age-matched controls and confirmed statistically significant elevation in the mI in our cases. In conclusion, 1H-MRS alterations were suggestive of neuronal loss and inflammation in these patients. 1H-MRS may be a valuable tool in monitoring the disease progress and response to therapy in GM2 gangliosidoses. Elevation in the mI may prove to be more sensitive than the other metabolite alterations.

Multi-Voxel 1H-MRS in Metachromatic Leukodystrophy

Metachromatic leukodystrophy (MLD) is characterized by the accumulation of sulfatide sphingolipids in the brain and peripheral nerves. We report metabolite alterations recorded using multi-voxel proton spectroscopy of the brain in four children with MLD. The data revealed elevated myoinositol/creatine and lactate/creatine ratios as well as decreased N-acetyl aspartate/creatine ratios. We propose that elevation in myoinositol and lactate are caused by astrocytic gliosis and may be used as biomarkers for disease progression in MLD.

Tc SPECT scan in a patient with occipital lobe infarction and complex visual hallucinations.

We have described a patient with occipital lobe infarction and CVH in the hemianopic field. Increased uptake in the right temporal lobe was documented on the brain Tc SPECT scan. We propose that activation of this area might be the underlying mechanism for visual hallucinations. This case report is a clear example of the wide spectrum of the clinical manifestations in stroke victims. We also emphasize the importance of educating the medical staff about the organic basis for human behavior.

Vitamin K Antagonist Warfarin for Palliative Treatment of Metachromatic Leukodystrophy, A Compassionate Study of Four Subjects

MLD is characterized by accumulation of sulfatides in the brain. Vitamin K regulates two enzymes in sphingolipid biosynthesis and warfarin is known to lower brain sulfatides in rats and mice. We hypothesized that warfarin may mitigate the MLD phenotype by reducing the formation of sulfatides. This compassionate study recruited four advanced patients with clinical, biochemical and genetic confirmation of MLD. The patients were treated with warfarin according to the approved protocol for a total of 45 days. The battery of tests included proton MR spectroscopy (H-MRS) of brain and urinary sulfatide levels recorded at defined intervals. The patients tolerated the medication and there were no bleeding complications. The urinary sulfatide levels did not decline during the study period. The H-MRS showed decreased N-acetyl aspartate and elevated myoinositol levels in the basal ganglia which remained unchanged after treatment. Our study did not demonstrate any beneficial effects of warfarin in four advanced cases of MLD. The drug intervention however, was safe and deserves further evaluation through a larger study of longer duration. The metabolite abnormalities reported on H-MRS may be useful in longitudinal follow up of patients with MLD during drug trials.

The prevalence, burden and cognizance of migraine in adolescent girls

Migraine represents a common neurological condition, which frequently affects adolescent girls. This cross sectional study aimed to evaluate the prevalence, impact and fund of migraine knowledge among adolescent girls. Students attending randomly selected high schools were recruited into the study by signing a consent form and completing a validated survey designed for this purpose. The survey assessed the participants fund of knowledge about migraine in five domains: migraine epidemiology, symptoms, triggers, auras and treatment options. The participants were evaluated for headache characteristics according to the International Classification of Headache Disorders, 2nd edition criteria, and categorized as having definite migraine or probable migraine. Additionally, the survey evaluated headache disability by implementing the headache impact test-6, and collected information regarding the use of over-the-counter medication. In a cohort of 309 girls, 14-18 years old, 18% fulfilled the criteria for definite migraine and 25% for probable migraine, with mean headache impact test-6 scores of 62.5 and 55.2, respectively ( P< 0.0001). Furthermore, the students fund of knowledge was substantially limited in regards to migraine auras and moderately limited in regards to symptoms, triggers and treatments. A significant portion of the migraineurs self-medicated using over-the-counter medications. The prevalence of migraine in late adolescent girls is very close to that of adult women. The information regarding the cognizance of migraine ought to be used as a guideline for designing educational tools for this population.