Biomedical subjects

Mário Campos

Publications and source records attributed to Mário Campos.

4 recordsLinked to original sources

PubMed2006

Low significance of MECP2 mutations as a cause of mental retardation in Brazilian males.

MeCP2 is a protein that selectively binds to methylated cytosines through its methyl-CpG-binding domain (MBD) and connects DNA methylation to transcriptional repression. Mutations in MECP2 gene, located in Xq28, have been reported as being the major cause of Rett syndrome and are also associated with some cases of X-linked mental retardation in both males and females. In this study, we present the first screening in the MECP2 gene in a Brazilian cohort of 239 unrelated males with idiopathic mental retardation. Eight sequence variations were observed in 10 patients: one novel putative pathogenic variant, two never described variants of unknown pathogenic value and five non-pathogenic variations. We conclude that in mentally retarded Brazilian males, non-pathogenic variants in the MECP2 gene are more common than actual pathogenic mutations, and therefore alterations in this gene have a weak relationship with mental retardation in males.

Adult↗

PubMed2006

Lack of FMR3 expression in a male with non-syndromic mental retardation and a microdeletion immediately distal to FRAXE CCG repeat.

FRAXE fragile site associated mental retardation (FRAXE MR) belongs to a group of non-syndromic X-linked mental retardation. Two genes, FMR2 and FMR3 (likely a non-coding RNA) are transcribed from the FRAXE CpG island in the opposite directions. While the contribution of the FMR2 gene to FRAXE MR has been demonstrated, the role of the FMR3 gene is not known. We have screened 441 Brazilian mentally handicapped males for CCG repeat expansions in the FMR2 gene and identified a boy with a mutation (c.-414_-357del58) immediately distal to the FRAXE CCG repeat. We have established a skin fibroblast cell line from this patient and tested expression of both FMR2 and FMR3 genes. Reverse transcriptase PCR studies on the FMR2 and FMR3 genes showed that only the FMR3 gene transcription was abolished, suggesting a possible causal relationship between the lack of FMR3 expression and mental retardation in this patient. In the literature, there have been few deletions described near the FRAXE CCG repeat, but none was followed with expression studies. This is the first study showing missing expression in the FMR3 gene with normal FMR2 transcription leading to FRAXE mutation-likely phenotype. The FMR3 gene is likely a non-coding RNA gene. So far all individuals with FRAXE CCG repeat expansions and cytogenetically detectable FRAXE fragile site have both FMR2 and FMR3 gene expression abolished. Although the function of the FMR3 gene is not known, our present study together with previous studies on FRAXE MR suggest that it may play role in the processes underpinning normal learning and memory.

Adolescent↗

PubMed2005

The A140V mutation in the MECP2 gene is not a common etiological factor among Brazilian mentally retarded males.

In mammals, methyl-CpG binding proteins play a significant role in the control of gene expression through their association with chromatin-remodeling complexes. Mutations in the gene coding for methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome and have also been reported in a number of X-linked mental retardation diseases. In this study, DNA samples from 363 male individuals with syndromic and non-syndromic mental retardation and other psychiatric diseases were screened for A140V (419C>T) mutation in the MECP2 gene, considered the most frequent MECP2 mutation in males. No 419C>T was found suggesting that the A140V mutation in the MECP2 gene is not a common cause of mental retardation in males. Recently, a new and abundant isoform of MECP2 was described, which has an alternative N-terminus, translated from exon 1, that was previously thought to be non-coding and has been excluded from many mutational screening, as well, the 5' and 3' UTR regions. We consider essential proceeding further screening in the whole extension of the MECP2 gene using clinically well-documented and larger sized sample to assure the overall contribution of MECP2 to mental retardation.

Adolescent↗

PubMed2005

Lupus myocarditis. Case report.

Myocarditis is one of the many possible forms of cardiac involvement in systemic lupus erythematosus. Its clinical presentation ranges from asymptomatic patients with self-limited disease to fulminant heart failure that can lead to death. In most cases treatment consists of supportive care only. The authors present the case of a patient with lupus myocarditis.

Adolescent↗