An investigation of ribosomal protein L10 gene in autism spectrum disorders

<p>Abstract</p> <p>Background</p> <p>Autism spectrum disorders (ASD) are severe neurodevelopmental disorders with the male:female ratio of 4:1, implying the contribution of X chromosome genetic factors to the susceptibility of ASD. The ribosomal protein L10 (RPL10) gene, located on chromosome Xq28, codes for a key protein in assembling large ribosomal subunit and protein synthesis. Two non-synonymous mutations of <it>RPL10</it>, L206M and H213Q, were identified in four boys with ASD. Moreover, functional studies of mutant RPL10 in yeast exhibited aberrant ribosomal profiles. These results provided a novel aspect of disease mechanisms for autism – aberrant processes of ribosome biosynthesis and translation. To confirm these initial findings, we re-sequenced <it>RPL10 </it>exons and quantified mRNA transcript level of <it>RPL10 </it>in our samples.</p> <p>Methods</p> <p>141 individuals with ASD were recruited in this study. All <it>RPL10 </it>exons and flanking junctions were sequenced. Furthermore, mRNA transcript level of <it>RPL10 </it>was quantified in B lymphoblastoid cell lines (BLCL) of 48 patients and 27 controls using the method of SYBR Green quantitative PCR. Two sets of primer pairs were used to quantify the mRNA expression level of <it>RPL10</it>: RPL10-A and RPL10-B.</p> <p>Results</p> <p>No non-synonymous mutations were detected in our cohort. Male controls showed similar transcript level of RPL10 compared with female controls (RPL10-A, U = 81, P = 0.7; RPL10-B, U = 61.5, P = 0.2). We did not observe any significant difference in RPL10 transcript levels between cases and controls (RPL10-A, U = 531, P = 0.2; RPL10-B, U = 607.5, P = 0.7).</p> <p>Conclusion</p> <p>Our results suggest that RPL10 has no major effect on the susceptibility to ASD.</p

Vitamin D in the general population of young adults with autism in the Faroe Islands

Vitamin D deficiency has been proposed as a possible risk factor for developing autism spectrum disorder (ASD). 25-Hydroxyvitamin D3 (25(OH)D3) levels were examined in a cross-sectional population-based study in the Faroe Islands. The case group consisting of a total population cohort of 40 individuals with ASD (aged 15–24 years) had significantly lower 25(OH)D3 than their 62 typically-developing siblings and their 77 parents, and also significantly lower than 40 healthy age and gender matched comparisons. There was a trend for males having lower 25(OH)D3 than females. Effects of age, month/season of birth, IQ, various subcategories of ASD and Autism Diagnostic Observation Schedule score were also investigated, however, no association was found. The very low 25(OH)D3 in the ASD group suggests some underlying pathogenic mechanism

Variations of the Candidate SEZ6L2 Gene on Chromosome 16p11.2 in Patients with Autism Spectrum Disorders and in Human Populations

Background: Autism spectrum disorders (ASD) are a group of severe childhood neurodevelopmental disorders with still unknown etiology. One of the most frequently reported associations is the presence of recurrent de novo or inherited microdeletions and microduplications on chromosome 16p11.2. The analysis of rare variations of 8 candidate genes among the 27 genes located in this region suggested SEZ6L2 as a compelling candidate. Methodology/Principal Findings: We further explored the role of SEZ6L2 variations by screening its coding part in a group of 452 individuals, including 170 patients with ASD and 282 individuals from different ethnic backgrounds of the Human Genome Diversity Panel (HGDP), complementing the previously reported screening. We detected 7 previously unidentified non-synonymous variations of SEZ6L2 in ASD patients. We also identified 6 non-synonymous variations present only in HGDP. When we merged our results with the previously published, no enrichment of non-synonymous variation in SEZ6L2 was observed in the ASD group compared with controls. Conclusions/Significance: Our results provide an extensive ascertainment of the genetic variability of SEZ6L2 in human populations and do not support a major role for SEZ6L2 sequence variations in the susceptibility to ASD

Analysis of X chromosome inactivation in autism spectrum disorders.

International audienceAutism spectrum disorders (ASD) are complex genetic disorders more frequently observed in males. Skewed X chromosome inactivation (XCI) is observed in heterozygous females carrying gene mutations involved in several X-linked syndromes. In this study, we aimed to estimate the role of X-linked genes in ASD susceptibility by ascertaining the XCI pattern in a sample of 543 informative mothers of children with ASD and in a sample of 163 affected girls. The XCI pattern was also determined in two control groups (144 adult females and 40 young females) with a similar age distribution to the mothers sample and affected girls sample, respectively. We observed no significant excess of skewed XCI in families with ASD. Interestingly, two mothers and one girl carrying known mutations in X-linked genes (NLGN3, ATRX, MECP2) showed highly skewed XCI, suggesting that ascertainment of XCI could reveal families with X-linked mutations. Linkage analysis was carried out in the subgroup of multiplex families with skewed XCI (> or = 80:20) and a modest increased allele sharing was obtained in the Xq27-Xq28 region, with a peak Z-score of 1.75 close to rs719489. In summary, our results suggest that there is no major X-linked gene subject to XCI and expressed in blood cells conferring susceptibility to ASD. However, the possibility that rare mutations in X-linked genes could contribute to ASD cannot be excluded. We propose that the XCI profile could be a useful criteria to prioritize families for mutation screening of X-linked candidate genes

Mutations in the gene encoding the synaptic scaffolding protein SHANK3 are associated with autism spectrum disorders.

International audienceSHANK3 (also known as ProSAP2) regulates the structural organization of dendritic spines and is a binding partner of neuroligins; genes encoding neuroligins are mutated in autism and Asperger syndrome. Here, we report that a mutation of a single copy of SHANK3 on chromosome 22q13 can result in language and/or social communication disorders. These mutations concern only a small number of individuals, but they shed light on one gene dosage-sensitive synaptic pathway that is involved in autism spectrum disorders

Meta-analysis of SHANK Mutations in Autism Spectrum Disorders: A Gradient of Severity in Cognitive Impairments.

International audienceSHANK genes code for scaffold proteins located at the post-synaptic density of glutamatergic synapses. In neurons, SHANK2 and SHANK3 have a positive effect on the induction and maturation of dendritic spines, whereas SHANK1 induces the enlargement of spine heads. Mutations in SHANK genes have been associated with autism spectrum disorders (ASD), but their prevalence and clinical relevance remain to be determined. Here, we performed a new screen and a meta-analysis of SHANK copy-number and coding-sequence variants in ASD. Copy-number variants were analyzed in 5,657 patients and 19,163 controls, coding-sequence variants were ascertained in 760 to 2,147 patients and 492 to 1,090 controls (depending on the gene), and, individuals carrying de novo or truncating SHANK mutations underwent an extensive clinical investigation. Copy-number variants and truncating mutations in SHANK genes were present in ∼1% of patients with ASD: mutations in SHANK1 were rare (0.04%) and present in males with normal IQ and autism; mutations in SHANK2 were present in 0.17% of patients with ASD and mild intellectual disability; mutations in SHANK3 were present in 0.69% of patients with ASD and up to 2.12% of the cases with moderate to profound intellectual disability. In summary, mutations of the SHANK genes were detected in the whole spectrum of autism with a gradient of severity in cognitive impairment. Given the rare frequency of SHANK1 and SHANK2 deleterious mutations, the clinical relevance of these genes remains to be ascertained. In contrast, the frequency and the penetrance of SHANK3 mutations in individuals with ASD and intellectual disability-more than 1 in 50-warrant its consideration for mutation screening in clinical practice

Boys with Asperger Syndrome grow up: psychiatric and neurodevelopmental disorders 20 years after initial diagnosis

We examined comorbid psychiatric and neurodevelopmental disorders in fifty adult males (mean age 30 years) with Asperger syndrome (AS) diagnosed in childhood and followed up prospectively for almost two decades (13–26 years). Only three of the 50 men had never met criteria for an additional psychiatric/neurodevelopmental diagnosis and more than half had ongoing comorbidity (most commonly either ADHD or depression or both). Any psychiatric comorbidity increased the risk of poorer outcome. The minority of the AS group who no longer met criteria for a full diagnosis of an autism spectrum disorder were usually free of current psychiatric comorbidity. The high rate of psychiatric/neurodevelopmental comorbidities underscores the need for a full psychiatric/neurodevelopmental assessment at follow-up of males with AS

Asperger syndrome in males over two decades: stability and predictors of diagnosis

Objective: To examine the diagnostic stability of a childhood diagnosis of Asperger Syndrome (AS) into adulthood in a prospective longitudinal study, and identify the predictors of stability. Methods: One hundred males with AS diagnosed in childhood (T0) according to Gillberg's AS criteria, were followed up prospectively into adulthood over an average of 19 years (range 13–26 years). Fifty males (mean age 30 years) participated in this second follow‐up (T2) of the cohort. Seventy‐six had participated in a previous follow‐up (T1) at mean age 22 years (47 participated in both follow‐ups). Diagnosis at T2 was assessed using three sets of diagnostic criteria (Gillberg's AS criteria, DSM‐IV Pervasive Developmental Disorder (PDD) and DSM‐5 Autism Spectrum Disorder (ASD) criteria) and compared to previous assessments. Background predictors of diagnostic stability were analyzed. General functioning at T2 was assessed and compared to T1. Results: There was a decline in the stability of AS diagnosis over time, the rate dropping from 82% at T1 to 44% at T2, when using the Gillberg criteria. There was also a significant decrease in the rate of cases fulfilling any PDD diagnosis according to the DSM‐IV, from 91% at T1 to 76% at T2 in the 47 cases followed up twice. Severity of autism spectrum symptoms at T1 was the main predictor of diagnostic stability at T2. Twenty percent of those meeting criteria for a PDD diagnosis according to DSM‐IV, did not meet DSM‐5 ASD criteria although they had marked difficulties in everyday life. Conclusion: Asperger Syndrome, when considered as an ASD/PDD diagnosis, was fairly stable into adulthood, but there was a significant increase over time in cases no longer meeting criteria for an ASD diagnosis according to the DSM‐IV, or AS according to the Gillberg criteria. Cases with a stable diagnosis showed significantly more core ASD symptoms in adolescence/young adulthood

Asperger syndrome in males over two decades: Quality of life in relation to diagnostic stability and psychiatric comorbidity

This study examined objective quality of life (work, academic success, living situation, relationships, support system) and subjective quality of life (Sense of Coherence and Short-Form Health Survey-36) in an adult sample of males (n = 50, mean age: 30 years) with Asperger syndrome diagnosed in childhood and followed prospectively over two decades. The association between long-term diagnostic stability of an autism spectrum disorder and/or comorbid psychiatric disorders with quality of life was also examined. The results showed great variability as regards quality of life. The subsample that no longer fulfilled an autism spectrum disorder had full-time jobs or studies (10/11), independent living (100%), and reported having two or more friends (100%). In the stable autism spectrum disorder group, 41% had full-time job or studies, 51% lived independently, and 33% reported two or more friends, and a significant minority had specialized employments, lived with support from the government, or had no friends. Academic success was positively correlated with IQ. A majority of the total group scored average Sense of Coherence scores, and the mean for Short-Form Health Survey-36 was above average regarding psychical health and below average regarding mental health. Stability of autism spectrum disorder diagnosis was associated with objective but not subjective quality of life, while psychiatric comorbidity was associated with subjective but not objective quality of life