RESUMO
Marfan syndrome (MFS) is an autosomal dominant disease of the connective tissue that affects the ocular, skeletal and cardiovascular systems, with a wide clinical variability. Although mutations in the FBN1 gene have been recognized as the cause of the disease, more recently other loci have been associated with MFS, indicating the genetic heterogeneity of this disease. We addressed the issue of genetic heterogeneity in MFS by performing linkage analysis of the FBN1 and TGFBR2 genes in 34 families (345 subjects) who met the clinical diagnostic criteria for the disease according to Ghent. Using a total of six microsatellite markers, we found that linkage with the FBN1 gene was observed or not excluded in 70.6 percent (24/34) of the families, and in 1 family the MFS phenotype segregated with the TGFBR2 gene. Moreover, in 4 families linkage with the FBN1 and TGFBR2 genes was excluded, and no mutations were identified in the coding region of TGFBR1, indicating the existence of other genes involved in MFS. Our results suggest that the genetic heterogeneity of MFS may be greater that previously reported.
Assuntos
Feminino , Humanos , Masculino , Heterogeneidade Genética , Ligação Genética/genética , Síndrome de Marfan/genética , Proteínas dos Microfilamentos/genética , Fator de Crescimento Transformador beta/genética , Distribuição de Qui-Quadrado , Estudos de Coortes , Marcadores Genéticos , Escore Lod , Taxa de Mutação , Síndrome de Marfan/diagnósticoRESUMO
We selected 114 dysmorphic syndromes, and based on published data, have elaborated a general picture, including characteristic clinical, radiological and pathological signs. This database was prepared to run on personal computers. lt is possible to browse or search for the syndromes, features and references, among other characteristics.The dysmorphic syndromes were divided into two different sets, according to their mode of inheritance. The first comprises 78 monogenic syndromes with defined inheritance, while the second comprises 36 presently undefined syndromes with suggested monogenic inheritance. Among the first group, 53 have autosomal recessive inheritance. Although in almost half of the syndromes death is mostly perinatal, longer survival can be found. The organic systems involved among the 114 syndromes studied were as follows: Osteoarticular 81 per cent, cardiovascular 54 per cent, genitourinary 47 per cent, central nervous system 42 per cent, respiratory 41 per cent and gastrointestinal 37 per cent. Abnormalities of the osteoarticular system was the main cause of death in the majority of the syndromes.