Cognitive Assessment System (CAS): A review

This paper presents a review of literature of cognitive Assessment system (CAS) developed by J. P. Das and Jack A. Naglieri in1997 following their PASS theory (Planning, Attention, Successive & Simultaneous) based on Luria�s model of neuropsychological processing. CAS is a reliable measure of cognitive functioning which has proved its validity across cultures. CAS is acquiring professional status in assessment of multiple as well as specific neuropsychological processing over the past 27 years. The battery has also resulted in remedial tests such as PREP (PASS Remedial Enhancement Program). This paper traces the CAS through important research papers published in various international journals and books between 1983 and 2012

Neurocognitive profile of children with reading disability in Kannada

Background: The present study was based on the Planning, Attention, Simultaneous, and Successive processes (PASS) theory. Objectives: We hypothesized that there would be significant differences between children with and without reading disability (RD) on PASS components. Furthermore, we predicted that deficits in children with RD would not be uniform across PASS components. Patients and Methods: Children with RD who participated in the study were two grades below the expected reading level for their age but were otherwise normal with respect to intellectual functioning, opportunities, and instructions. The comparison group consisted of age-matched children. Results: Independent-samples t tests (two-tailed) showed significant difference between the groups on all the PASS component subtests. The PASS scores of children with RD were scattered unevenly around the average to well below the average range. Conclusions: Kannada children with RD were particularly poor on simultaneous and successive processing. Our results support the heterogeneity view of RD

Analysis of genetic variants of dyslexia candidate genes KIAA0319 and DCDC2 in Indian population

Developmental dyslexia (DD) is a heritable, complex genetic disorder associated with impairment in reading and writing skills despite having normal intellectual ability and appropriate educational opportunities. Chromosome 6p23-21.3 at DYX2 locus has showed the most consistent evidence of linkage for DD and two susceptible genes KIAA0319 and DCDC2 for DD at DYX2 locus showed significant association. Specific candidate gene-Association studies have identified variants, risk haplotypes and microsatellites of KIAA0319 and DCDC2 correlated with wide range of reading-related traits. In this study, we used a case-control approach for analyzing single-nucleotide polymorphisms (SNPs) in KIAA0319 and DCDC2. Our study demonstrated the association of DD with SNP rs4504469 of KIAA0319 and not with any SNPs of DCDC2

Copy number variation-based polymorphism in a new pseudoautosomal region 3 (PAR3) of a human X-chromosome-transposed region (XTR) in the y chromosome

A 3.5-Mb region of the X chromosome underwent duplication and transposition to the Y chromosome �5-6 Mya. This X-transposed-region (XTR) originated at Xq21.3 and was inserted at Yp11.2. The two locations have 98.78 % homology and a high concentration of tandem repeats. In whole-genome scans of ten large families with dyslexic members, we identified transposed blocks comprising \textgreater102 kb of the Yp11.2 region in its homologous region at Xq21.3 in three females from three different families. Although recombination is known to be limited only to the pseudoautosomal regions (PARs) of the X and Y chromosomes, we report allelic unequal recombination between the XTR region Yp11.2 and Xq21.3, indicating the presence of a new PAR, which we named PAR3. This PAR3 region was also found in 2 % of the general population. An additional layer of justification could be provided from six other dyslexic cases which harbored duplications and deletions in the same Xq21.3 and Yp11.2 regions through allelic unequal recombination

SU15 - Integrated whole exome sequencing and homozygosity mapping identifies variants in known and novel autism genes involved in neuronal migration and adhesion pathways

Background Genetic heterogeneity of autism makes it challenging to identify the causal genes responsible for its pathogenesis. Although many genes are reported to be associated with autism, recent studies report only a handful of high confidence genes for autism. No disease gene saturation level is attained. There is a need to identify damaging genomic variants which predispose an individual towards autism manifestation. Methods Whole Exome Sequencing (WES) is a reliable technique to identify DNA variants in the coding region of the genome. Based on stringent inclusion-exclusion criteria, the study recruited 50 autism subjects of Indian origin, of which 13 were used for WES. PCR based Fragile X screening was performed to avoid the subjects with autism features. Results Several damaging stop gain/loss mutations encompassing autism genes CDH5, DDX23, CLDN5, and DPP3) were identified with protein truncations ranging from 20�70. These loss of function mutations disrupted important protein domains involved in various autism related pathways such as neuronal migration, synaptic pruning, synaptogenesis, and neuronal adhesion. Homozygosity mapping analysis to identify risk homozygous haplotypes in probands showed evidence of recessive polymorphisms in GIGYF1, SERPINE1, and EPHB6. These recessive alleles were identified across all the samples while polymorphisms in FOLH1, BCKDK, CDH11, and CTCF were specific to few samples. Mutations in language-specific genes, GCFC1 and MRPL19 were found associated with delayed speech language phenotype of autism. Several autism candidate genes WBP11, JMJD6, RBM8A, TRMT2A were identified. Discussion A novel autism candidate gene CLDN5 that physically interacts with genes involved in various autism pathways was identified contributing to the phenotype. CLDN5 was found belonging to the leukocyte transendothelial migration pathway and elevated in autism cortex, impairing the blood brain barrier leading to compensatory gene expression and protein accumulation. This on-going study identified several mutations specific for autism in Indian population, adding to the growing body of mutational spectrum. The implications of these findings will be presented and discussed

Distinctive neural signatures for negative sentences in Hindi: An FMRI study

We examined cortical activations using functional magnetic resonance imaging (fMRI) technique in skilled native Hindi readers while they performed a `target-probe' semantic judgment task on affirmative and negative sentences. Hindi, an Indo-Aryan language widely spoken in India, follows subject-object-verb (SOV) order canonically but allows free word order. The common cortical regions involved in affirmative and negative sentence conditions included bilateral inferior frontal gyrus (IFG), left parietal cortex (BA 7/40), left fusiform (BA 37), bilateral supplementary motor area (SMA) (BA 6), bilateral middle temporal gyrus (BA 21), and bilateral occipital area (BA 17/18). While no distinct region was activated for affirmative sentences, we observed activations in the region of bilateral anterior temporal pole for negative sentence. The behavioral results showed no significant mean difference for reaction times (RT) and accuracy measures between affirmative and negative sentences. However, the imaging results suggest the recruitment of anterior temporal pole in processing of negative sentences. Region of interest (ROI) analysis for selected regions showed higher signal intensity for negative sentences possibly indicating the associated inherent difficulty level of processing, especially when integrating information related to negations

Family based genome-wide copy number scan identifies complex rearrangements at 17q21.31 in dyslexics

Developmental dyslexia (DD) is a complex heritable disorder with unexpected difficulty in learning to read and spell despite adequate intelligence, education, environment, and normal senses. We performed genome-wide screening for copy number variations (CNVs) in 10 large Indian dyslexic families using Affymetrix Genome-Wide Human SNP Array 6.0. Results revealed the complex genomic rearrangements due to one non-contiguous deletion and five contiguous micro duplications and micro deletions at 17q21.31 region in three dyslexic families. CNVs in this region harbor the genes KIAA1267, LRRC37A, ARL17A/B, NSFP1, and NSF. The CNVs in case 1 and case 2 at this locus were found to be in homozygous state and case 3 was a de novo CNV. These CNVs were found with at least one CNV having a common break and end points in the parents. This cluster of genes containing NSF is implicated in learning, cognition, and memory, though not formally associated with dyslexia. Molecular network analysis of these and other dyslexia related module genes suggests NSF and other genes to be associated with cellular/vesicular membrane fusion and synaptic transmission. Thus, we suggest that NSF in this cluster would be the nearest gene responsible for the learning disability phenotype