Browsing by Author "Borges, L."
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- Brief report: High frequency of biochemical markers for mitochondrial dysfunction in autism: no association with the mitochondrial aspartate/glutamate carrier SLC25A12 genePublication . Correia, C.; Coutinho, A.M.; Diogo, L.; Grazina, M.; Marques, C.; Miguel, T.; Ataíde, A.; Almeida, J.; Borges, L.; Oliveira, C.; Oliveira, G.; Vicente, A.M.In the present study we confirm the previously reported high frequency of biochemical markers of mitochondrial dysfunction, namely hyperlactacidemia and increased lactate/pyruvate ratio, in a significant fraction of 210 autistic patients. We further examine the involvement of the mitochondrial aspartate/glutamate carrier gene (SLC25A12) in mitochondrial dysfunction associated with autism. We found no evidence of association of the SLC25A12 gene with lactate and lactate/pyruvate distributions or with autism in 241 nuclear families with one affected individual. We conclude that while mitochondrial dysfunction may be one of the most common medical conditions associated with autism, variation at the SLC25A12 gene does not explain the high frequency of mitochondrial dysfunction markers and is not associated with autism in this sample of autistic patients.
- MECP2 coding sequence and 3'UTR variation in 172 unrelated autistic patientsPublication . Coutinho, A.M.; Oliveira, G.; Katz, C.; Feng, J.; Yan, J.; Yang, C.; Marques, C.; Ataíde, A.; Miguel, T.S.; Borges, L.; Almeida, J.; Correia, C.; Currais, A.; Bento, C.; Mota-Vieira, L.; Temudo, T.; Santos, M.; Maciel, P.; Sommer, S.S.; Vicente, A.M.Mutations in the coding sequence of the methyl-CpG-binding protein 2 gene (MECP2), which cause Rett syndrome (RTT), have been found in male and female autistic subjects without, however, a causal relation having unequivocally been established. In this study, the MECP2 gene was scanned in a Portuguese autistic population, hypothesizing that the phenotypic spectrum of mutations extends beyond the traditional diagnosis of RTT and X-linked mental retardation, leading to a non-lethal phenotype in male autistic patients. The coding region, exon-intron boundaries, and the whole 3'UTR were scanned in 172 patients and 143 controls, by Detection of Virtually All Mutations-SSCP (DOVAM-S). Exon 1 was sequenced in 103 patients. We report 15 novel variants, not found in controls: one missense, two intronic, and 12 in the 3'UTR (seven in conserved nucleotides). The novel missense change, c.617G > C (p.G206A), was present in one autistic male with severe mental retardation and absence of language, and segregates in his maternal family. This change is located in a highly conserved residue within a region involved in an alternative transcriptional repression pathway, and likely alters the secondary structure of the MeCP2 protein. It is therefore plausible that it leads to a functional modification of MeCP2. MECP2 mRNA levels measured in four patients with 3'UTR conserved changes were below the control range, suggesting an alteration in the stability of the transcripts. Our results suggest that MECP2 can play a role in autism etiology, although very rarely, supporting the notion that MECP2 mutations underlie several neurodevelopmental disorders.