Conclusion: The authors estimate the prevalence of CAS in galactosemia at 18 per hundred—180 times the estimated risk for idiopathic CAS. Findings support the need to study risk factors for the high occurrence of motor speech disorders in galactosemia despite early compliant dietary management.
Reading disabilities (RD) have been linked and associated with markers on chromosome 6p with results from multiple independent samples pointing to KIAA0319 as a risk gene and specifically, the 5′ region of this gene. Here we focus genetic studies on a 2.3 kb region spanning the predicted promoter, the first untranslated exon, and part of the first intron, a region we identified as a region of open chromatin. Using DNA from probands with RD, we screened for genetic variants and tested select variants for association. We identified 17 DNA variants in this sample of probands, 16 of which were previously reported in public databases and one previously identified in a screen of this region. Based on the allele frequencies in the probands compared to public databases, and on possible functional consequences of the variation, we selected seven variants to test for association in a sample of families with RD, in addition to four variants which had been tested previously. We also tested two markers 5′ of this region that were previously reported as associated. The strongest evidence for association was observed with alleles of the microsatellite marker located in the first untranslated exon and haplotypes of that marker. These results support previous studies indicating the 5′ region of the KIAA0319 gene as the location of risk alleles contributing to RD.
from Behavior Genetics
Asperger disorder (ASP) is one of the autism spectrum disorders (ASD) and is differentiated from autism largely on the absence of clinically significant cognitive and language delays. Analysis of a homogenous subset of families with ASP may help to address the corresponding effect of genetic heterogeneity on identifying ASD genetic risk factors. To examine the hypothesis that common variation is important in ASD, we performed a genome-wide association study (GWAS) in 124 ASP families in a discovery data set and 110 ASP families in a validation data set. We prioritized the top 100 association results from both cohorts by employing a ranking strategy. Novel regions on 5q21.1 (P = 9.7 × 10−7) and 15q22.1–q22.2 (P = 7.3 × 10−6) were our most significant findings in the combined data set. Three chromosomal regions showing association, 3p14.2 (P = 3.6 × 10−6), 3q25–26 (P = 6.0 × 10–5) and 3p23 (P = 3.3 × 10−4) overlapped linkage regions reported in Finnish ASP families, and eight association regions overlapped ASD linkage areas. Our findings suggest that ASP shares both ASD-related genetic risk factors, as well as has genetic risk factors unique to the ASP phenotype.
from Autism Research
This paper has provided an overview of mutation with some of the genes and/or loci discovered to be the cause for auditory neuropathy spectrum disorders (ANSDs). It has been noted that different gene mutations may trigger different pathological changes in patients with this disorder. These discoveries have provided us with vital information as to the sites of pathology in auditory neuropathy spectrum disorders (ANSDs), and the results highlight the heterogeneity of the disorder.
this study represents one of the first endophenotypic research proposals on stuttering characterized by two aspects: objective inclusion criteria and the type of stuttering symptomatology manifested.
The FOXP2 gene is mutated in a severe monogenic form of speech and language deficits, but no study on the influence of genetic variations within FOXP2 in neurological disorders characterized by language impairment is available yet. In the present study, we investigated the impact of common FOXP2 polymorphisms with regard to frontotemporal lobar degeneration (FTLD). Two-hundred ten FTLD patients underwent clinical and a wide standardized neuropsychological examination as well as brain imaging study. In all patients, and in 200 age-matched healthy controls, four FOXP2 polymorphisms were evaluated, namely rs2396753, rs1456031, rs17137124 and rs1852469. SPECT images were analyzed by Statistical Parametric Mapping (SPM5). No significant differences of the four FOXP2 polymorphisms in genotype distribution and allele frequency between FTLD and controls were observed. A significant and specific association between rs1456031 TT and rs17137124 TT genotypes and verbal fluency scores was reported. The two polymorphisms showed an addictive effect. When the analysis was computed on the number of observations over time, and 391 assessments considered, comparable results were obtained. FTLD patients carrying at-risk polymorphisms showed greater hypoperfusion in the frontal areas, namely the left inferior frontal gyrus, and putamen, compared to the non-carriers (p < 0.005). Genetic variations within FOXP2 do not represent a genetic risk to FTLD per se, but modulate FTLD presentation when disease is overt, affecting language performances and leading to hypoperfusion in language-associated brain areas.
from the Journal of Alzheimer’s Disease
We examined the Simple View of reading from a behavioral genetic perspective. Two aspects of word decoding (phonological decoding and word recognition), two aspects of oral language skill (listening comprehension and vocabulary), and reading comprehension were assessed in a twin sample at age 9. Using latent factor models, we found that overlap among phonological decoding, word recognition, listening comprehension, vocabulary, and reading comprehension was primarily due to genetic influences. Shared environmental influences accounted for associations among word recognition, listening comprehension, vocabulary, and reading comprehension. Independent of phonological decoding and word recognition, there was a separate genetic link between listening comprehension, vocabulary, and reading comprehension and a specific shared environmental link between vocabulary and reading comprehension. There were no residual genetic or environmental influences on reading comprehension. The findings provide evidence for a genetic basis to the “Simple View” of reading.
from the Annals of Dyslexia
Impact of Chromosome 4p- Syndrome on Communication and Expressive Language Skills: A Preliminary Investigation
Results broaden the spectrum of expressive language skills associated with Chromosome 4p- syndrome and highlight the communication potential of a subset of individuals with 4p abnormalities for development of advanced language structures. It is hypothesized that the largest 4p deletion, which includes the 4p16.3 band and contiguous gene regions, results in the most severely affected expressive language phenotype.
Cx30 mutations do not contribute to the autosomal recessive non-syndromic hearing loss (NSHL) in the Indian population. Homozygous Cx26 mutations account only for about 1/5th (18.8%) of autosomal recessive non-syndromic hearing implying the need to explore other contributory loci.
Otosclerosis is a common form of hearing loss characterized by abnormal bone remodeling in the otic capsule. It is a complex genetic disease, caused by a combination of genetic and environmental factors. During the past decade, several attempts have been made to identify factors for otosclerosis. This review provides an overview of the current understanding of the etiology of otosclerosis and describes the genetic and environmental factors that have been implicated in the disease. Environmental factors include fluoride and viral factors, particularly measles. Genetic association studies for otosclerosis have reported several associations of genetic variants that influence the risk of disease, mainly involving bone remodeling pathways, although their individual risk contributions are small. Rare monogenic forms of otosclerosis also exist, which are caused by a mutation in a single gene leading to a clear familial segregation of the disease. Linkage analysis of large otosclerosis families has led to the identification of seven loci, and recently evidence was found that T cell receptor beta is a gene responsible for familial otosclerosis, suggesting an underlying immunological pathway. However, this might also represent an autoimmune process, a hypothesis that is supported by other data as well. In conclusion, a variety of pathways have been identified to be involved in the development of otosclerosis, showing that distinct mechanisms involving both genetic and environmental risk factors can influence and contribute to a similar disease outcome.
from The Laryngoscope
In order to test the hypothesis that the genetic etiology of reading disability differs as a function of IQ, composite reading performance data from 308 pairs of identical (monozygotic, MZ) twins and 440 pairs of fraternal (dizygotic, DZ) twins (254 same-sex and 186 opposite-sex) in which at least one member of each pair was classified as reading-disabled were subjected to multiple regression analysis (DeFries and Fulker, Behav Genet 15:467–473, 1985; Acta Genet Med Gemellol 37:205–216, 1988). In the total sample, heritability of the group deficit in reading performance (hg2) was .61 (±.06). However, results of fitting an extended regression model to reading performance and IQ data suggested that the genetic etiology of reading disability differs as a linear function of IQ (p ≤ .04). When the basic regression model was fitted separately to data from twin pairs with Wechsler (Examiner’s manual: Wechsler intelligence scale for children—revised, 1974; Examiner’s manual: Wechsler adult intelligence scale—revised, 1981) Full Scale IQ scores in the upper and lower 25% of the sample, resulting estimates of hg2 were .75 (±.12) and .50 (±.10), respectively (p ≤ .045). These results suggest that reading difficulties in children with a higher IQ are due substantially to genetic influences and may require intensive remediation efforts.
from Behavior Genetics
Genetic Influences on Language, Reading, and Mathematics Skills in a National Sample: An Analysis Using the National Longitudinal Survey of Youth
Conclusion: The present study provides additional support for significant genetic effects across low and wide ranges of specific achievement. Moreover, this study supports that genetic influences on reading, language, and mathematics are generalizable beyond twin and adoption studies.
Purpose: Conceptual and methodological confounds occur when non(sense) word repetition tasks are administered to speakers who do not have the target speech sounds in their phonetic inventories or who habitually misarticulate targeted speech sounds. In this article, the authors (a) describe a nonword repetition task, the Syllable Repetiton Task (SRT), that eliminates this confound and (b) report findings from 3 validity studies.
Method: Ninety-five preschool children with speech delay and 63 with typical speech completed an assessment battery that included the Nonword Repetition Task (NRT; C. Dollaghan & T. F. Campbell, 1998) and the SRT. SRT stimuli include only 4 of the earliest occurring consonants and 1 early occurring vowel.
Results: Study 1 findings indicated that the SRT eliminated the speech confound in nonword testing with speakers who misarticulate. Study 2 findings indicated that the accuracy of the SRT to identify expressive language impairment was comparable to findings for the NRT. Study 3 findings illustrated the SRT’s potential to interrogate speech processing constraints underlying poor nonword repetition accuracy. Results supported both memorial and auditory–perceptual encoding constraints underlying nonword repetition errors in children with speech-language impairment.
Conclusion: The SRT appears to be a psychometrically stable and substantively informative nonword repetition task for emerging genetic research and other research with speakers who misarticulate.
Conclusion: The SRT appears to be a psychometrically stable and substantively informative nonword repetition task for emerging genetic and other research with speakers who misarticulate.