RESUMO
The ABCB1 gene, coding for the efflux transporter P-glycoprotein (PGP), is a candidate gene for Alzheimer disease (AD). P-glycoprotein is heavily expressed at the blood-brain barrier, where it mediates the efflux of ß-amyloid (Aß) from the brain. In this study, we investigated a possible association between 2 common ABCB1 polymorphisms, G2677T/A (Ala893Ser/Thr) and C3435T, AD, and cerebrospinal fluid (CSF) levels of Aß. No strong evidence for association was found.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Doença de Alzheimer/líquido cefalorraquidiano , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Subfamília B de Transportador de Cassetes de Ligação de ATP , Idoso , Alelos , Feminino , Frequência do Gene , Estudos de Associação Genética , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Razão de Chances , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Linkage to 7q has been the most robust genetic finding in familial autism. A previous scan of multiplex families with autism spectrum disorders found a linkage signal of genome-wide significance at D7S530 on 7q32. We searched a candidate imprinted region at this location for genetic variants in families with positive linkage scores. Using exon resequencing, we identified three rare potentially pathogenic variants in the TSGA14 gene, which encodes a centrosomal protein. Two variants were missense mutations (c.664C>G; p.P206A and c.766T>G; p.C240G) that changed conserved residues in the same protein domain; the third variant (c.192+5G>A) altered splicing, which resulted in a protein with an internal deletion of 16 residues and a G33D substitution. These rare TSGA14 variants are enriched in the affected subjects (6/348 patients versus 2/670 controls, Fisher's exact two tailed P = 0.022). This is the first report of a possible link of a gene with a centrosomal function with familial autism.
Assuntos
Transtornos Globais do Desenvolvimento Infantil/genética , Mutação/genética , Proteínas/genética , Alelos , Sequência de Aminoácidos , Estudos de Casos e Controles , Criança , Transtornos Globais do Desenvolvimento Infantil/etnologia , Cromossomos Humanos Par 7/genética , Família , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Desequilíbrio de Ligação/genética , Masculino , Dados de Sequência Molecular , Linhagem , Proteínas/química , Splicing de RNA/genética , População Branca/genéticaRESUMO
Autism spectrum disorders are a group of highly heritable neurodevelopmental disorders with a complex genetic etiology. The International Molecular Genetic Study of Autism Consortium previously identified linkage loci on chromosomes 7 and 2, termed AUTS1 and AUTS5, respectively. In this study, we performed a high-density association analysis in AUTS1 and AUTS5, testing more than 3000 single nucleotide polymorphisms (SNPs) in all known genes in each region, as well as SNPs in non-genic highly conserved sequences. SNP genotype data were also used to investigate copy number variation within these regions. The study sample consisted of 127 and 126 families, showing linkage to the AUTS1 and AUTS5 regions, respectively, and 188 gender-matched controls. Further investigation of the strongest association results was conducted in an independent European family sample containing 390 affected individuals. Association and copy number variant analysis highlighted several genes that warrant further investigation, including IMMP2L and DOCK4 on chromosome 7. Evidence for the involvement of DOCK4 in autism susceptibility was supported by independent replication of association at rs2217262 and the finding of a deletion segregating in a sib-pair family.
