Genetic Screening of Selected Disease-Causing Mutations in Glutaryl-CoA Dehydrogenase Gene among Indian Patients with Glutaric Aciduria Type I.

Glutaric aciduria type I (GA-I) is an organic aciduria caused by glutaryl-CoA dehydrogenase (GCDH) deficiency. There are limited studies on GA-I from India. A total of 48 Indian GA-I patients were screened for selected disease-causing mutations such as R402W, A421V, A293T, R227P, and V400M using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Among these patients, 9 (18.8%) had R402W mutation, and none had A421V, A293T, R227P, or V400M mutation. One low excretor mutation (P286S) and several novel mutations (I152M, Q144P, and E414X) were also found in this study. We conclude that among selected mutations, R402W is the most common mutation found among Indian GA-I patients.

Whole gene duplication of SCN2A and SCN3A is associated with neonatal seizures and a normal intellectual development.

Duplications at 2q24.3 encompassing the voltage-gated sodium channel gene cluster are associated with early onset epilepsy. All cases described in the literature have presented in addition with different degrees of intellectual disability, and have involved neighbouring genes in addition to the sodium channel gene cluster. Here, we report eight new cases with overlapping duplications at 2q24 ranging from 0.05 to 7.63 Mb in size. Taken together with the previously reported cases, our study suggests that having an extra copy of SCN2A has an effect on epilepsy pathogenesis, causing benign familial infantile seizures which eventually disappear at the age of 1-2 years. However, the number of copies of SCN2A does not appear to have an effect on cognitive outcome.

Diagnostic strategy for mucolipidosis II/III.

Overlapping clinical phenotypes are a diagnostic challenge to the clinician, especially in the cases of mucolipidosis (ML) and mucopolysaccharide disorders (MPS), due to overlapping phenotypes. Present study was carried out in 147 children suspected to have ML or MPS and 100 controls. They were screened for ML II/III by colorimetric method using substrate pNCS. Six children were found screen positive for ML II/III and further confirmatory study showed significantly raised activity in plasma confirming high specificity of the ML screening test. Forty-two (28.5%) children out of remaining 141 children that were screen negative, were found to have various MPS disorders, while rest 99 had normal enzyme activity in plasma and leucocytes. Present study demonstrates prompt and specific chemical method that can be used as a tool for estimating ML II/III, with high specificity.