Mahesh Kamate

Molecular and structural analysis of metachromatic leukodystrophy patients in Indian population

Metachromatic leukodystrophy (MLD) is an autosomal recessive disorder caused by mutations in arylsulfatase A (ARSA) gene. No work on molecular genetics of MLD has been reported from India and the mutational spectrum in Indian patients is not known. The present study was undertaken to identify mutations in arylsulfatase A gene in Indian MLD patients, to evaluate genotype-phenotype correlation, and to see the effect of the novel mutants on the protein. Twenty MLD patients (16 families) were screened by ARMS PCR for the most common mutation (c.459+1G>A). Pseudodeficiency alleles were tested by RFLP method whereas rare and novel mutations were scanned by Conformation Sensitive Gel Electrophoresis (CSGE), followed by sequencing. The genotype-phenotype correlation was also attempted. Protein homology modeling analysis was carried out for two novel missense mutations identified, to assess the effect of these mutations on the protein conformation. Nine pathogenic alleles were found in 13 patients (65%). Four previously reported mutations and five novel variants were identified. Five patients (35%) were found to have pseudodeficiency alleles, c.1049A>G (p.Asn350Ser) and c.1524+95A>G. Genotype-phenotype correlation was found to be difficult to establish. Protein modeling studies showed that the mutations cause loss of interactions leading to conformational change in ASA protein. The study identified the mutational spectrum of Indian MLD patients, which will be helpful in genetic counseling, carrier detection and establishing prenatal diagnosis. Homology modeling helped to study conformational change in protein and has implications in generating novel therapeutic molecules.

Efficacy and Tolerability of Lacosamide as an Adjunctive Therapy in Children With Refractory Partial Epilepsy

BACKGROUND A unicentre, prospective study was performed to investigate the efficacy of lacosamide as adjunctive therapy in children with refractory partial epilepsy. METHODS The study was performed at a tertiary care hospital over a period of 30 months between November 2011 and May 2014. Seventy-nine children with refractory partial epilepsy (age 5-15 years) who had failed two or more antiepileptic drugs and in whom lacosamide was used as an add-on drug were enrolled. Lacosamide tablets were administered orally, at a dose of 25 mg for 1 week followed by 50 mg twice daily for the remaining period. Efficacy and tolerability evaluation was performed at every visit of titration, maintenance period (3 months), and two follow-up visits at monthly interval. Electrocardiogram and liver function tests were performed before enrollment and at the end of 3 months of lacosamide therapy. Patients caregiver or investigator observed adverse events were recorded in a predesigned pro forma. RESULTS A total of 79 patients with uncontrolled partial epilepsy screened from 531 epileptic children were enrolled, after they satisfied the inclusion and exclusion criteria. The mean age of children enrolled was 8.8 ± 3.1 years (range 5-15 years); 53 children (67.0%) were boys. Mean weight of the patients was 24.2 ± 9.8 kg. The mean age at the onset of seizures was 6.4 ± 3.5 years. The mean dose of lacosamide administered was 4.1 mg/kg. Three patients (3.8%) dropped out of the study, because of vomiting, aggressive behavior, and poor response, respectively. Of 76 patients (96.2%) entering the maintenance period, 35 patients (44.3%) were seizure free, 32 patients (40.6%) indicated ≥50% reduction in seizure frequency, 3 patients (3.8%) indicated 25-49% seizure reduction, and 9 patients (11.4%) either had no change in seizure frequency or experience increase in seizure frequency. CONCLUSION Lacosamide is an effective add-on antiepileptic drug for children with refractory partial epilepsy and is well tolerated.

Glutaric aciduria type I: A treatable neurometabolic disorder.

Background and Objectives: Glutaric aciduria Type-I (GA-I) has characteristic clinical and neuroimaging features, which clinches the diagnosis in a majority of patients. However, there have been few case reports on GA-I from India. This study was undertaken to study the clinical presentations, metabolic profile, neuroimaging findings and outcome of patients with GA-I. Study Design: The present study was a retrospective study. Materials and Methods: Retrospective review of charts of patients with a diagnosis of GA-I was carried out from March 2008 to April 2010. The clinical, laboratory and neuroimaging findings were extracted in a predesigned proforma and the data was analyzed. Results: Eleven cases were found to have GA-1. Clinical presentation was quite varied. Follow-up of patients revealed that one patient with macrocephaly as the only clinical finding was developmentally normal. One patient with encephalitis-like illness steadily improved and started walking at 2 years. Two patients were bed ridden and had severe dystonia. One patient died during follow-up. The remaining six patients had dystonia and other abnormal movements, but had attained sitting without support and were not ambulatory. Conclusion: GA-I is not an uncommon disorder and diagnosis can be made easily based on clinical, laboratory investigations and neuroimaging findings. It is one of the treatable metabolic disorders and, if managed appropriately, favorable prognosis can be given.

SCIWORA-Spinal Cord Injury Without Radiological Abnormality.

Following trauma, the commonly used radiological investigations, plain radiographs and computed tomography (CT) studies do not rule out injury to the spinal cord. This is especially true for children, as an entity known by the acronym SCIWORA (spinal cord injury without radiological abnormality) exists and the changes may be picked up only on magnetic resonance imaging (MRI). Early treatment (within 6 hours) with high dose methylprednisolone improves the outcome. Spinal trauma being common it is possible that the burden of neurological handicap following this can be reduced by increasing awareness and early treatment with steroids. In the community, pediatricians are often the first medical contact after spinal trauma and awareness of the lacune of conventional imaging techniques is important especially if clinical symptoms pertaining to the spine are present. The community pediatrician is hereby made aware of the need to investigate spinal trauma with a MRI for possible SCIWORA situation as it generates a possiblity for therapeutic intervention to alter the outcome positively.

Lead Encephalopathy in an Infant Mimicking a Neurometabolic Disorder

We report the case of a 7-month-old child who presented with regression of milestones, seizures, altered sensorium, and vomiting. An elder sibling had died of similar complaints. Lead encephalopathy was considered because of presence of microcytic hypochromic anemia and dense metaphyseal bands on wrist radiogram. Magnetic resonance imaging (MRI) of the brain revealed diffuse dysmyelination involving both periventricular and subcortical white matter. Such diffuse changes have not been described previously. The child’s father was operating an illicit lead-acid battery manufacturing unit at home. The child was subjected to chelation therapy, which was accompanied by environmental exposure source modification. He showed significant improvement. Our case highlights the importance of taking a detailed occupational history and considering lead poisoning in the differential diagnosis of encephalopathy of unidentifiable cause.

Recurrent and novel GLB1 mutations in India.

GM1 gangliosidosis is a lysosomal storage disorder caused by mutations in the GLB1 gene, leading to the deficiency of the enzyme β-d-galactosidase. In this study, we report molecular findings in 50 Asian Indian families with GM1 gangliosidosis. We sequenced all the exons and flanking intronic sequences of GLB1 gene. We identified 33 different mutations (20 novel and 13 previously reported). The novel mutations include 12 missense (p.M1?, p.E129Q, p.G134R, p.L236P, p.G262E, p.L297F, p.Y331C, p.G414V, p.K493N, p.L514P, p.P597L, p.T600I), four splicing (c.246-2A>G, c.397-2A>G, c.552+1G>T, c.956-2A>G), three indels (p.R22Qfs*8, p.L24Cfs*47, p.I489Qfs*4) and one nonsense mutation (p.Q452*). Most common mutations identified in this study were c.75+2InsT (14%) and p.L337P (10%). Known mutations accounted for 67% of allele frequency in our cohort of patients, suggesting that these mutations in GLB1 are recurrent across different populations. Twenty three mutations were localized in the TIM barrel domain, β-domain 1 and β-domain 2. In silico sequence and structure analysis of GLB1 reveal that all the novel mutations affect the function and structure of the protein. We hereby report on the largest series of patients with GM1 gangliosidosis and the first from India.

Molecular Genetic Studies in Indian Patients With Megalencephalic Leukoencephalopathy

Mutations in the MLC1 gene cause megalencephalic leukoencephalopathy with subcortical cysts. We sought to identify mutations in the MLC1 gene, to evaluate the genotype-phenotype correlation, and to develop a strategy for diagnosing Indian patients with megalencephalic leukoencephalopathy. Forty patients were enrolled. We developed a rapid restriction fragment length polymorphism method to screen a common mutation, c.135_136insC. Rare and novel mutations were screened by conformation-sensitive gel electrophoresis, followed by sequencing. Three previously reported and two novel mutations were identified in 37 patients. The presence of the c.135_136insC mutation in 29 patients of the Agarwal community suggests a founder effect. The mutation c.959C>A was evident in four patients, and appears to be the second commonest mutation. Genotype could not predict phenotype. We recommend screening for the commonest mutation (c.135_136insC), followed by the next commonest mutation (c.959C>A), and then other rare mutations, using conformation-sensitive gel electrophoresis analysis or direct sequencing.

Predominant Corticospinal Tract Involvement in Early-Onset Krabbe Disease

Krabbe disease has characteristic findings on brain magnetic resonance imaging (MRI) according to age at clinical onset. Knowledge of the characteristic brain MRI findings contributes to rapid and specific diagnosis of Krabbe disease in the proper clinical setting. In the early-onset form of Krabbe disease, the leading imaging findings are signal abnormalities within cerebellar white matter, the deep gray nuclei, parieto-occipital white matter, and corpus callosum, and the pyramidal tract. In late-onset disease, MRI is characterized by signal abnormalities within the pyramidal tract, posterior corpus callosum, and parietooccipital white matter [1]. Although cases of Krabbe diseasewith selective involvement of corticospinal tract only have been reported in adults, case reports of children with predominant involvement of corticospinal tracts have been very few [1-3]. We present the case of a 2-year-old boy with late infantile onset Krabbe disease with proven enzyme deficiency and predominant involvement of corticospinal tracts on MRI as the initial feature without other characteristic features of Krabbe disease.

Profile of inborn errors of metabolism in a tertiary care centre PICU.

ObjectiveTo study the clinico-investigative profile and outcome of patients with inborn errors of metabolism (IEM) presenting to the pediatric intensive care unit (PICU).MethodsRecords of all patients admitted in tertiary care centre PICU between August 2007 and September 2008 with a diagnosis of IEM were retrieved the details of clinical presentation, laboratory results, treatment and outcome were noted and analysed.ResultsEleven (2.6%) out of 420 PICU admissions during the study period had a diagnosis of IEM with a high mortality rate of 36%. Clinical presentation was quite varied.ConclusionIEM are not uncommon in PICU. Simple biochemical tests and neuroimaging findings provide vital clues to the diagnosis of IEM.

‘Reversible Inattention and hyperactivity in a child on Lacosamide - In south Indian Subpopulation’

Lacosamide is a newer antiepileptic drug with a novel mode of action and is being increasingly used in children as an add-on drug in the treatment of refractory epilepsy. Its safety, efficacy and tolerance in adults, favorable pharmacokinetic profiles are encouraging its use in children. Because of lack of large studies in children the full spectrum of side effects of this drug in children is not clear. Though behavioral problems like agitation and worsening behavior have been mentioned in the earlier case reports and retrospective studies, there has been no emphasis on the inattention and hyperactivity. We here report an epileptic child on lacosamide who developed severe hyperactivity, aggression and inattention one week after starting the drug. It continued for one month till the drug was continued and the behavior then reverted to normal status after the drug was stopped. The knowledge of this important side effect and its reversibility should be considered when lacosamide is considered in a child.