Identification of NCAN as a candidate gene for developmental dyslexia.

A whole-genome linkage analysis in a Finnish pedigree of eight cases with developmental dyslexia (DD) revealed several regions shared by the affected individuals. Analysis of coding variants from two affected individuals identified rs146011974G > A (Ala1039Thr), a rare variant within the NCAN gene co-segregating with DD in the pedigree. This variant prompted us to consider this gene as a putative candidate for DD.

Polymorphisms in DCDC2 and S100B associate with developmental dyslexia.

Genetic studies of complex traits have become increasingly successful as progress is made in next-generation sequencing. We aimed at discovering single nucleotide variation present in known and new candidate genes for developmental dyslexia: CYP19A1, DCDC2, DIP2A, DYX1C1, GCFC2 (also known as C2orf3), KIAA0319, MRPL19, PCNT, PRMT2, ROBO1 and S100B. We used next-generation sequencing to identify single-nucleotide polymorphisms in the exons of these 11 genes in pools of 100 DNA samples of Finnish individuals with developmental dyslexia.

The aromatase gene CYP19A1: several genetic and functional lines of evidence supporting a role in reading, speech and language.

Inspired by the localization, on 15q21.2 of the CYP19A1 gene in the linkage region of speech and language disorders, and a rare translocation in a dyslexic individual that was brought to our attention, we conducted a series of studies on the properties of CYP19A1 as a candidate gene for dyslexia and related conditions. The aromatase enzyme is a member of the cytochrome P450 super family, and it serves several key functions: it catalyzes the conversion of androgens into estrogens; during early mammalian development it controls the differentiation of specific brain areas (e.

Human ROBO1 regulates interaural interaction in auditory pathways.

In rodents, the Robo1 gene regulates midline crossing of major nerve tracts, a fundamental property of the mammalian CNS. However, the neurodevelopmental function of the human ROBO1 gene remains unknown, apart from a suggested role in dyslexia. We therefore studied axonal crossing with a functional approach, based on magnetoencephalography, in 10 dyslexic individuals who all share the same rare, weakly expressing haplotype of the ROBO1 gene.

SNP variations in the 7q33 region containing DGKI are associated with dyslexia in the Finnish and German populations.

Four genes, DYX1C1, ROBO1, DCDC2 and KIAA0319 have been studied both genetically and functionally as candidate genes for developmental dyslexia, a common learning disability in children. The identification of novel genes is crucial to better understand the molecular pathways affected in dyslectic individuals. Here, we report results from a fine-mapping approach involving linkage and association analysis in Finnish and German dyslexic cohorts.

A locus on 2p12 containing the co-regulated MRPL19 and C2ORF3 genes is associated to dyslexia.

DYX3, a locus for dyslexia, resides on chromosome 2p11-p15. We have refined its location on 2p12 to a 157 kb region in two rounds of linkage disequilibrium (LD) mapping in a set of Finnish families. The observed association was replicated in an independent set of 251 German families.

The axon guidance receptor gene ROBO1 is a candidate gene for developmental dyslexia.

Dyslexia, or specific reading disability, is the most common learning disorder with a complex, partially genetic basis, but its biochemical mechanisms remain poorly understood. A locus on Chromosome 3, DYX5, has been linked to dyslexia in one large family and speech-sound disorder in a subset of small families. We found that the axon guidance receptor gene ROBO1, orthologous to the Drosophila roundabout gene, is disrupted by a chromosome translocation in a dyslexic individual.

Fine mapping of the 2p11 dyslexia locus and exclusion of TACR1 as a candidate gene.

Developmental dyslexia, or reading disability, is a multigenic complex disease for which at least five loci, i.e. DYX1-3 and DYX5-6, have been clearly identified from the human genome.

A candidate gene for developmental dyslexia encodes a nuclear tetratricopeptide repeat domain protein dynamically regulated in brain.

Approximately 3-10% of people have specific difficulties in reading, despite adequate intelligence, education, and social environment. We report here the characterization of a gene, DYX1C1 near the DYX1 locus in chromosome 15q21, that is disrupted by a translocation t(2;15)(q11;q21) segregating coincidentally with dyslexia. Two sequence changes in DYX1C1, one involving the translation initiation sequence and an Elk-1 transcription factor binding site (-3G --> A) and a codon (1249G --> T), introducing a premature stop codon and truncating the predicted protein by 4 aa, associate alone and in combination with dyslexia.

A genome scan for developmental dyslexia confirms linkage to chromosome 2p11 and suggests a new locus on 7q32.

Developmental dyslexia is a distinct learning disability with unexpected difficulty in learning to read despite adequate intelligence, education, and environment, and normal senses. The genetic aetiology of dyslexia is heterogeneous and loci on chromosomes 2, 3, 6, 15, and 18 have been repeatedly linked to it. We have conducted a genome scan with 376 markers in 11 families with 38 dyslexic subjects ascertained in Finland.

Familial dyslexia: neurocognitive and genetic correlation in a large Finnish family.

Neuropsychological findings of individuals with dyslexia (n=24) from a large, three-generation Finnish family are presented. We have previously performed whole genome linkage scanning in this family and found that dyslexia in this kindred segregates with a single locus in the pericentromeric area of chromosome 3. Those included in the analyses were carefully evaluated for general cognitive ability, reading and spelling skills, and reading-related neurocognitive skills.

A dominant gene for developmental dyslexia on chromosome 3.

Developmental dyslexia is a neurofunctional disorder characterised by an unexpected difficulty in learning to read and write despite adequate intelligence, motivation, and education. Previous studies have suggested mostly quantitative susceptibility loci for dyslexia on chromosomes 1, 2, 6, and 15, but no genes have been identified yet. We studied a large pedigree, ascertained from 140 families considered, segregating pronounced dyslexia in an autosomal dominant fashion.

Two translocations of chromosome 15q associated with dyslexia.

Developmental dyslexia is characterised by difficulties in learning to read. As reading is a complex cognitive process, multiple genes are expected to contribute to the pathogenesis of dyslexia. The genetics of dyslexia has been a target of molecular studies during recent years, but so far no genes have been identified.