Functional New World monkey oxytocin forms elicit an altered signaling profile and promotes parental care in rats.

The neurohormone oxytocin is a key player in the modulation of reproductive and social behavioral traits, such as parental care. Recently, a correlation between different forms of oxytocin and behavioral phenotypes has been described in the New World Monkeys (NWMs). Here, we demonstrate that, compared with the Leu8OXT found in most placental mammals, the Cebidae Pro8OXT and Saguinus Val3Pro8OXT taxon-specific variants act as equi-efficacious agonists for the Gq-dependent pathway but are weaker agonists for the ß-arrestin engagement and subsequent endocytosis toward the oxytocin receptor (OXTR). Upon interaction with the AVPR1a, Pro8OXT and the common Leu8OXT yielded similar signaling profiles, being equally efficacious on Gq and ß-arrestin, while Val3Pro8OXT showed reduced relative efficacy toward ß-arrestin. Intranasal treatment with either of the variants increased maternal behavior and also promoted unusual paternal care in rats, as measured by pup-retrieval tests. We therefore suggest that Val3Pro8OXT and Pro8OXT are functional variants, which might have been evolutionarily co-opted as an essential part of the adaptive genetic repertoire that allowed the emergence of taxon-specific complex social behaviors, such as intense parental care in the Cebidae and the genus Saguinus.

Progesterone Response Element Variation in the OXTR Promoter Region and Paternal Care in New World Monkeys.

Paternal care is a complex social behavior common in primate species with socially monogamous mating systems and twin births. Evolutionary causes and consequences of such behavior are not well understood, nor are their neuroendocrine and genetic bases. However, the neuropeptide oxytocin (OXT) and its receptor (OXTR) are associated with parental care in mammalian lineages. Here we investigated the interspecific variation in the number of progesterone response elements (PREs) in the OXTR promoter region of 32 primate species, correlating genetic data with behavior, social systems, and ecological/life-history parameters, while controlling for phylogeny. We verified that PREs are only present in New World monkeys and that PRE number is significantly correlated with the presence of paternal care in this branch. We suggest that PRE number could be an essential part of the genetic repertoire that allowed the emergence of taxon-specific complex social behaviors, such as paternal care in marmosets and tamarins.

Analysis of a Protein Network Related to Copy Number Variations in Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, with strong genetic influences as evidenced by its high heritability. Submicroscopic variations (ranging from one kilobase to several megabases) in DNA, called copy number variations (CNVs), have been associated with psychiatric diseases, including ASD. We aimed to identify CNVs in children diagnosed with idiopathic ASD. We used microarray-based comparative genomic hybridization analysis to detect the CNVs, and bioinformatic tools to evaluate their pathogenic potential, based on predicted functional aspects. Using combined cytogenetic and bioinformatic tools, we identified an autism network of genes/proteins related to the CNVs. Among the 40 children analyzed, we found 14 potentially pathogenic CNVs, including those previously associated with ASD (located at 16p11.2, 15q11.2, and 7p21 regions). We suggest that the most relevant biological process and functional attributes involve olfactory receptors. The CNV-related autism network comprised 90 proteins and 754 nodes and indicated the family of olfactory receptors as a significant pathway in ASD. Olfactory receptors were previously associated with neurologic diseases, and they are possibly related to cognition. This integrative analysis that combines cytogenetics and bioinformatics is a promising approach to understand complex conditions such as ASD.

Evidence for Association Between OXTR Gene and ASD Clinical Phenotypes.

Autism spectrum disorder (ASD) is an early-onset neurodevelopmental disorder characterized by impairments in social behaviors and communication. Oxytocin and its signaling pathway are related to a range of human behaviors, from facial expression recognition to aggressive behaviors, and have been suggested as involved in the etiology of ASD. Our aim was to evaluate the influence of two polymorphisms (rs1042778, rs53576) at the oxytocin receptor gene (OXTR) on ASD diagnosis and on specific ASD-related clinical symptoms (seizures, panic, and aggressive behaviors). We also assessed if these SNPs could be related to changes in OXTR availability and functionality using a bioinformatic approach. The sample was composed by 209 probands with ASD and their biological parents. Family-based approach and logistic regression models were used to investigated the outcomes. We observed that panic and aggressive behaviors were nominally associated with presence of rs1042778 T allele (P = 0.019/Pcorr = 0.114; P = 0.046/Pcorr = 0.276 respectively). Also, in the family-based analysis, a trend towards association with ASD susceptibility was observed for rs1042778 (G allele) (P = 0.066). In a bioinformatic approach, we demonstrated that rs1042778 G allele is determinant for the binding of the transcription factor MAZ, suggesting that when the T allele is present, the absence of MAZ binding might be associated with lower transcription levels of the OXTR gene. The overall findings suggest that the OXTR gene may play a role in ASD diagnosis and some of its clinical phenotypes, supported by previous animal and clinical studies. Further investigations are necessary to replicate our findings and fully understand the effects of the oxytocin pathway on ASD.

The role of ß3 integrin gene variants in Autism Spectrum Disorders--diagnosis and symptomatology.

Autism Spectrum Disorders (ASDs) represent a group of very complex early-onset neurodevelopmental diseases. In this study, we analyzed 5 SNPs (rs2317385, rs5918, rs15908, rs12603582, rs3809865) at the ß3 integrin locus (ITGB3), which has been suggested as a possible susceptibility gene, both as single markers and as part of haplotypes in 209 ASD children and their biological parents. We tested for association with the following: a) DSM-IV ASD diagnosis; b) clinical symptoms common in ASD patients (repetitive behaviors, echolalia, seizures and epilepsy, mood instability, aggression, psychomotor agitation, sleep disorders); and c) dimensional scores obtained with the Autism Screening Questionnaire and the Childhood Autism Rating Scale. These hypotheses were investigated using family-based tests, logistic regression models and analysis of covariance. The family-based tests showed an association with the H5 haplotype (composed by GTCGA alleles, the order of SNPs as above), which was transmitted less often than expected by chance (P=0.006; Pcorr=0.036). The analyses of the clinical symptoms showed a trend for an association with rs12603582 (P=0.008; Pcorr=0.064) and positive results for the haplotype composed of rs15908 and rs12603582 (Pglcorr=0.048; Pindcorr=0.015), both in symptoms of echolalia. Other nominal associations with different variants were found and involved epilepsy/seizures, aggression symptoms and higher ASQ scores. Although our positive results are not definitive, they suggest small effect associations of the ITGB3 gene with both ASD diagnosis and symptoms of echolalia. Other studies are nonetheless needed to fully understand the involvement of this locus on the etiology of ASDs and its different clinical aspects.

Implications of the admixture process in skin color molecular assessment.

The understanding of the complex genotype-phenotype architecture of human pigmentation has clear implications for the evolutionary history of humans, as well as for medical and forensic practices. Although dozens of genes have previously been associated with human skin color, knowledge about this trait remains incomplete. In particular, studies focusing on populations outside the European-North American axis are rare, and, until now, admixed populations have seldom been considered. The present study was designed to help fill this gap. Our objective was to evaluate possible associations of 18 single nucleotide polymorphisms (SNPs), located within nine genes, and one pseudogene with the Melanin Index (MI) in two admixed Brazilian populations (Gaucho, N = 352; Baiano, N = 148) with different histories of geographic and ethnic colonization. Of the total sample, four markers were found to be significantly associated with skin color, but only two (SLC24A5 rs1426654, and SLC45A2 rs16891982) were consistently associated with MI in both samples (Gaucho and Baiano). Therefore, only these 2 SNPs should be preliminarily considered to have forensic significance because they consistently showed the association independently of the admixture level of the populations studied. We do not discard that the other two markers (HERC2 rs1129038 and TYR rs1126809) might be also relevant to admixed samples, but additional studies are necessary to confirm the real importance of these markers for skin pigmentation. Finally, our study shows associations of some SNPs with MI in a modern Brazilian admixed sample, with possible applications in forensic genetics. Some classical genetic markers in Euro-North American populations are not associated with MI in our sample. Our results point out the relevance of considering population differences in selecting an appropriate set of SNPs as phenotype predictors in forensic practice.

Translation and validation of Autism Diagnostic Interview-Revised (ADI-R) for autism diagnosis in Brazil.

OBJECTIVE: To translate into Brazilian Portuguese the Autism Diagnostic Interview-Revised (ADI-R), an extremely useful diagnostic tool in autism. METHODS: A case-control study was done to validate the ADI-R. After being translated, the interview was applied in a sample of 20 patients with autism and 20 patients with intellectual disability without autism, in order to obtain the initial psychometric properties. RESULTS: The internal consistency was high, with a of Crombach of 0.967. The validity of criterion had sensitivity and specificity of 100%, having as a gold standard the DSM-IV diagnostic criteria. The interview had high discriminant validity, with higher scores in the group of patients with autism, as well as high interobserver consistency, with median kappa of 0.824. CONCLUSION: The final version of ADI-R had satisfactory psychometric characteristics, indicating good preliminary validation properties. The instrument needs to be applied in bigger samples in other areas of the country.

MTHFR C677T is not a risk factor for autism spectrum disorders in South Brazil.

Many studies have suggested that autism may be associated with metabolic abnormalities in the folate/homocysteine pathway, which is involved in DNA methylation, thus altering gene expression. One of the most important polymorphisms in this pathway is C677T of the methylenetetrahydrofolate reductase gene, because the T allele is associated with a decrease in enzymatic activity. We evaluated the association between C677T polymorphism and autism spectrum disorders through a case--control study. In addition, we analyzed the influence of this polymorphism on certain autistic behaviors like complex body movements, self-injury and averted gaze according to the Autism Diagnostic Interview-Revised. The analyses involved 151 children with idiopathic autism spectrum disorder and 100 healthy control children. The frequency of the T allele was 0.38 for the case group and 0.35 for the control group (P=0.77). The genotypic distribution did not show significant differences between cases and controls (P=0.72), nor association between the T allele and selected behaviors.

Influence of the 5-HTTLPR polymorphism and environmental risk factors in a Brazilian sample of patients with autism spectrum disorders.

The 5-HTTLPR polymorphism of serotonin transporter gene is widely investigated in association studies in autism spectrum disorders (ASD). The results of such studies, however, remain controversial possibly due to the great genetic heterogeneity related to ASD and the lack of evaluation of the triallelic functional structure of 5-HTTLPR. This study tested for association between the 5-HTTLPR and ASD in a Brazilian sample by case-control and family-based association test (FBAT) methods, considering the biallelic and triallelic structures of this polymorphism. In addition, we performed an exploratory analysis of associations between specific clinical outcomes of ASD patients and 5-HTTLPR as well as several prenatal environmental factors. Genotyping was achieved in 151 ASD patients, 179 unrelated controls and 105 complete trios. There was no evidence of association between the 5-HTTLPR with ASD in both case-control and FBAT tests, but the LaLa 5-HTTLPR genotype was associated with mood instability in patients (P=0.006). The prenatal exposure to potential neuroteratogenic drugs was associated with epilepsy (P<0.001). Our findings suggest that the 5-HTTLPR is not associated with ASD in the Brazilian population, even considering the triallelic structure. Additionally, this study suggested a role of the 5-HTTLPR and environmental factors in the clinical expression of ASD.

Translation and validation of Autism Diagnostic Interview-Revised (ADI-R) for autism diagnosis in Brazil / Tradução e validação da ADI-R (Autism Diagnostic Interview-Revised) para diagnóstico de autismo no Brasil

OBJECTIVE: To translate into Brazilian Portuguese the Autism Diagnostic Interview-Revised (ADI-R), an extremely useful diagnostic tool in autism. METHODS: A case-control study was done to validate the ADI-R. After being translated, the interview was applied in a sample of 20 patients with autism and 20 patients with intellectual disability without autism, in order to obtain the initial psychometric properties. RESULTS: The internal consistency was high, with a of Crombach of 0.967. The validity of criterion had sensitivity and specificity of 100 percent, having as a gold standard the DSM-IV diagnostic criteria. The interview had high discriminant validity, with higher scores in the group of patients with autism, as well as high interobserver consistency, with median kappa of 0.824. CONCLUSION: The final version of ADI-R had satisfactory psychometric characteristics, indicating good preliminary validation properties. The instrument needs to be applied in bigger samples in other areas of the country.

OBJETIVO: Traduzir para o português do Brasil a ADI-R (Autism Diagnostic Interview-Revised), uma ferramenta diagnóstica extremamente útil em casos de autismo. MÉTODOS: Foi realizado um estudo caso-controle para validar a ADI-R. A fim de se obter as propriedades psicométricas iniciais da entrevista, após a tradução, a ADI-R foi aplicada em uma amostra de 20 pacientes com autismo e 20 controles com retardo mental sem autismo. RESULTADOS: A consistência interna foi alta, com um a de Crombach de 0,976. A validade de critério mostrou uma sensibilidade e uma especificidade de 100 por cento, tendo os critérios diagnósticos do DSM-IV como padrão ouro. A entrevista teve uma alta validade discriminante, com maiores escores no grupo de pacientes com autismo, bem como uma alta consistência entre observadores, com um Kappa médio de 0,824. CONCLUSÃO: A versão final da ADI-R teve características psicométricas satisfatórias, indicando boas propriedades preliminares de validação. O instrumento necessita ser aplicado em amostras maiores em outras áreas do país.