Inherited Risk for Autism Through Maternal and Paternal Lineage (original) (raw)
Related papers
JAMA, 2014
IMPORTANCE Autism spectrum disorder (ASD) aggregates in families, but the individual risk and to what extent this is caused by genetic factors or shared or nonshared environmental factors remains unresolved. OBJECTIVE To provide estimates of familial aggregation and heritability of ASD. DESIGN, SETTING, AND PARTICIPANTS A population-based cohort including 2 049 973 Swedish children born 1982 through 2006. We identified 37 570 twin pairs, 2 642 064 full sibling pairs, 432 281 maternal and 445 531 paternal half sibling pairs, and 5 799 875 cousin pairs. Diagnoses of ASD to December 31, 2009 were ascertained. MAIN OUTCOMES AND MEASURES The relative recurrence risk (RRR) measures familial aggregation of disease. The RRR is the relative risk of autism in a participant with a sibling or cousin who has the diagnosis (exposed) compared with the risk in a participant with no diagnosed family member (unexposed). We calculated RRR for both ASD and autistic disorder adjusting for age, birth year, sex, parental psychiatric history, and parental age. We estimated how much of the probability of developing ASD can be related to genetic (additive and dominant) and environmental (shared and nonshared) factors. RESULTS In the sample, 14 516 children were diagnosed with ASD, of whom 5689 had autistic disorder. The RRR and rate per 100 000 person-years for ASD among monozygotic twins was estimated to be 153.0 (95% CI, 56.7-412.8; rate, 6274 for exposed vs 27 for unexposed); for dizygotic twins, 8.2 (95% CI, 3.7-18.1; rate, 805 for exposed vs 55 for unexposed); for full siblings, 10.3 (95% CI, 9.4-11.3; rate, 829 for exposed vs 49 for unexposed); for maternal half siblings, 3.3 (95% CI, 2.6-4.2; rate, 492 for exposed vs 94 for unexposed); for paternal half siblings, 2.9 (95% CI, 2.2-3.7; rate, 371 for exposed vs 85 for unexposed); and for cousins, 2.0 (95% CI, 1.8-2.2; rate, 155 for exposed vs 49 for unexposed). The RRR pattern was similar for autistic disorder but of slightly higher magnitude. We found support for a disease etiology including only additive genetic and nonshared environmental effects. The ASD heritability was estimated to be 0.50 (95% CI, 0.45-0.56) and the autistic disorder heritability was estimated to 0.54 (95% CI, 0.44-0.64). CONCLUSIONS AND RELEVANCE Among children born in Sweden, the individual risk of ASD and autistic disorder increased with increasing genetic relatedness. Heritability of ASD and autistic disorder were estimated to be approximately 50%. These findings may inform the counseling of families with affected children.
A unified genetic theory for sporadic and inherited autism
Proceedings of the National Academy of Sciences, 2007
Autism is among the most clearly genetically determined of all cognitive-developmental disorders, with males affected more often than females. We have analyzed autism risk in multiplex families from the Autism Genetic Resource Exchange (AGRE) and find strong evidence for dominant transmission to male offspring. By incorporating generally accepted rates of autism and sibling recurrence, we find good fit for a simple genetic model in which most families fall into two types: a small minority for whom the risk of autism in male offspring is near 50%, and the vast majority for whom male offspring have a low risk. We propose an explanation that links these two types of families: sporadic autism in the low-risk families is mainly caused by spontaneous mutation with high penetrance in males and relatively poor penetrance in females; and high-risk families are from those offspring, most often females, who carry a new causative mutation but are unaffected and in turn transmit the mutation in dominant fashion to their offspring.
Autism spectrum conditions (henceforth 'autism') refer to a group of neurodevelopmental conditions involving difficulties in social interaction and communication and unusually repetitive and restricted behaviours and interest. Twin and family studies have established a significant heritability for autism. Autism is polygenic with variations across the allele frequency spectrum contributing to risk. Early linkage and candidate gene association studies were statistically underpowered to identify significant loci. Current genome-wide association studies have identified significant positive genetic correlation between autism and various measures of cognition. The use of genetic microarrays and next-generation DNA sequencing has identified tens of genes and copy number variants associated with autism. In addition, RNA microarray and sequencing studies of postmortem brain samples have identified transcriptionally altered genes and pathways in autism. Multiple lines of evidence converge on altered glial, synaptic and chromatin pathways as contributing to autism risk. eLS
Journal of Child Psychology and Psychiatry, 2005
Background: The etiology of autism is unknown. A strong genetic component has been detected but non-genetic factors may also be involved in the etiology. Methods: We used data from the Danish Psychiatric Central Register and the Danish Civil Registration System to study some risk factors of autism, including place of birth, parental place of birth, parental age, family history of psychiatric disorders, and paternal identity. Results: A total of 943,664 children younger than ten years were followed from 1994 to 2001; of those, 818 children developed autism. The highest risks of autism were found in siblings of children with autism, or Asperger's syndrome and other pervasive developmental disorders (PDDs), with relative risks of 22 and 13, respectively. The relative risk of autism in the child was about twice as high if the mother had been diagnosed with a psychiatric disorder. The risk of autism was associated with increasing degree of urbanisation of the child's place of birth and with increasing paternal, but not maternal, age. An increased relative risk of 1.4 was found if the mother was born outside Europe, and in children of parents who were born in different countries. Conclusions: The highest risk of autism was found in families with a history of autism, or Asperger's syndrome and other PDDs in siblings, supporting the commonly accepted knowledge that genetic factors are involved in the etiology of autism.
The Genealogical Study of Autism
Autism is a developmental disability, usually showing up in children before age three. Autism interferes with the way a child interacts the world. It affects the way a child communicates, in both verbal and nonverbal ways, it affects social interaction, both physically and verbally, and lastly, it can cause a person to repeat behaviors or words. The aim of this study is to know and identify the origin of autism in a family, and who among the parents have the big contributions to the passing of the genes that carry autism, and how the external factors affect the development of this disorder. This study was conducted at Zion Christian Center, and three (3) families with cases of autism participated in this study. Through interviewing and Pedigree analysis the researchers were able to determine the genealogy of autism. The findings revealed that male are at greater risk for developmental disorders, such as autism, than females. Recommendations for parental styling for children with autism are thoroughly discussed in this study as well.
A Genome-Wide Survey of Transgenerational Genetic Effects in Autism
PLoS ONE, 2013
Effects of parental genotype or parent-offspring genetic interaction are well established in model organisms for a variety of traits. However, these transgenerational genetic models are rarely studied in humans. We have utilized an autism casecontrol study with 735 mother-child pairs to perform genome-wide screening for maternal genetic effects and maternaloffspring genetic interaction. We used simple models of single locus parent-child interaction and identified suggestive results (P,10 24 ) that cannot be explained by main effects, but no genome-wide significant signals. Some of these maternal and maternal-child associations were in or adjacent to autism candidate genes including: PCDH9, FOXP1, GABRB3, NRXN1, RELN, MACROD2, FHIT, RORA, CNTN4, CNTNAP2, FAM135B, LAMA1, NFIA, NLGN4X, RAPGEF4, and SDK1. We attempted validation of potential autism association under maternal-specific models using maternal-paternal comparison in familybased GWAS datasets. Our results suggest that further study of parental genetic effects and parent-child interaction in autism is warranted.
Evidence for a Susceptibility Gene for Autism on Chromosome 2 and for Genetic Heterogeneity
The American Journal of Human Genetics, 2001
Although there is considerable evidence for a strong genetic component to idiopathic autism, several genomewide screens for susceptibility genes have been performed with limited concordance of linked loci, reflecting either numerous genes of weak effect and/or sample heterogeneity. Because decreasing sample heterogeneity would increase the power to identify genes, the effect on evidence for linkage of restricting a sample of autism-affected relative pairs to those with delayed onset (at age 136 mo) of phrase speech (PSD, for phrase speech delay) was studied. In the second stage of a two-stage genome screen for susceptibility loci involving 95 families with two or more individuals with autism or related disorders, a maximal multipoint heterogeneity LOD score (HLOD) of 1.96 and a maximal multipoint nonparametric linkage (NPL) score of 2.39 was seen on chromosome 2q. Restricting the analysis to the subset of families ( ) with two or more individuals having a narrow diagnosis of autism and n p 49 PSD generated a maximal multipoint HLOD score of 2.99 and an NPL score of 3.32. The increased scores in the restricted sample, together with evidence for heterogeneity in the entire sample, indicate that the restricted sample comprises a population that is more genetically homogeneous, which could therefore increase the likelihood of positional cloning of susceptibility loci.
Autism Research, 2010
Zhao et al. [2007] in their ''Unified Theory of Autism'' hypothesized that incidence of autism in males could be explained by essentially two types of family structures: majority of autism cases are from low-risk autism families with de novo mutations, and a minority of cases are from high-risk multiplex families, where risk to male offspring approximates 50% consistent with a dominant model and high penetrance. Using the Autism Genetic Resource Exchange (AGRE) data set, Zhao et al. identified 86 high-risk families with likely dominant transmission. As genotype data are now available for many members of the AGRE resource, the objective of this manuscript was to determine if dominant linkage evidence for an autism predisposition gene exists in these 86 high-risk families. HumanHap550K Illumina SNP data were available for 92% of 455 total family members in these 86 high-risk families. We performed a linkage analysis using a pruned subset of markers where markers in high linkage disequilibrium were removed. We observed a single suggestive peak (maximum LOD 2.01, maximum HLOD 2.08) under a dominant model on chromosome Xp22.11-p21.2 that encompasses the IL1RAPL1 gene. Mutations or deletions in IL1RAPL1 have been previously reported in three families with autism. In our study, 11 families contributed nominally (Po0.05, HLOD40:588) to the chromosome X peak. These results demonstrate that identification of a more homogeneous subset of autism cases, which was based on family structure in this study, may help to identify, localize and further our understanding of autism predisposition genes.