SCN1A Gene Mutations in Indian Children With Epilepsy: Single Center Experience

Objective: To study prevalence of SCN1A gene mutations in complex seizure disorders. Methods: Retrospective laboratory based study on samples sent for molecular diagnosis in complex seizure disorders. Exome sequencing was performed. Phenotype- genotype correlation was done for patients showing variants in SCN1A gene. Results: 364 samples were evaluated; of which, 54% were of children below 5 years of age. SCN1A mutations were seen in 50 samples of patients with complex seizure disorders; 44 variants were identified. Types of seizure disorders commonly associated were Dravet syndrome and genetic epilepsy with febrile seizures. Conclusions: SCN1A mutations are common in complex seizure disorders, especially Dravet syndrome. Early identification of SCN1A gene in etiology is important for selection of correct antiepileptic and counselling.

Nucleotide sequence analysis of NIPBL gene in Indian Cornelia de Lange syndrome cases.

BACKGROUND: Cornelia de Lange syndrome (CdLS) is a multisystem developmental disorder in children. The disorder is caused mainly due to mutations in Nipped-B-like protein. The molecular data for CdLS is available from developed countries, but not available in developing countries like India. In the present study, the hotspot region of NIPBL gene was screened by Polymerase Chain Reaction which includes exon 2, 22, 42, and a biggest exon 10, in six CdLS patients and ten controls. MATERIALS AND METHODS: The method adopted in present study was amplification of the target exon by using polymerase chain reaction, qualitative confirmation of amplicons by Agarose Gel Electrophoresis and use of amplicons for Conformation Sensitive Gel Electrophoresis to find heteroduplex formation followed by sequencing. RESULTS: We report two polymorphisms in the studied region of gene NIPBL. The polymorphisms are in the region of intron 1 and in exon 10. The polymorphism C/A is present in intron 1 region and polymorphism T/G in exon 10. CONCLUSION: The intronic region polymorphism may have a role in intron splicing whereas the polymorphism in exon 10 results in amino acid change (Val to Gly). These polymorphisms are disease associated as these are found in CdLS patients only and not in controls.

Plasma chitotriosidase activity in children with lysosomal storage disorders.

Chitotriosidase (ChT) is an enzyme that is selectively activated in tissue macrophage. This property of ChT makes it a potential marker for many disease process and prognostication. Present study has been carried out to know the significance of ChT as a screening marker in lysosomal storage disorders (LSDs) where tissue macrophage activation is commonly observed due to accumulation of substrate in various organs of the body. Study comprises of 20 healthy children in the age range of 10 days to 5 yrs and 56 children in the age range of 2.5 months to 13 yrs with regression of milestones, skeletal dysplasia, neuroregression and hepatosplenomegaly were selected for plasma ChT who had confirmed LSDs as carried out by specific lysosomal enzyme study from the leukocytes or fibroblasts. Plasma ChT was 55.21 ± 20.81 nmol/ml /hr in twenty healthy age matched controls. Plamsa ChT level was 42.88 to 79.78 nmol/ml/hr in thirteen of 56 (23.21%) children with LSDs like Morquio- B, Pompe, Metachromatic leucodystrophy (MLD), Sandhoff and Niemann-Pick disease type C (NPD-C). While in 43 (76.78%) children it was in the range of 213.74 to 23,511.40 nmol/ml/hr. who had LSDs like Morquio-B, Sly syndrome, MLD, GM2 Gangliosidosis, NPD-A/B and Gaucher disease (GD). Marked elevated ChT (4,000 to 23,511 nmol/ml/hr) was observed in all cases of GD (n=7) and NDP-A/B. It can be concluded from the present study that moderately raised activity of ChT can be utilized as a positive predictive test for certain LSD’s. Those with marked elevated ChT have confirmed GD or NPD-A/B making it a strong screening marker for this group of diseases.