Cytogenetics investigation on orofacial cleft individuals and screening of informative cases for further studies / Investigação citogenetica em individuos com fendas orofaciais e triagem dos casos informativos para estudos especificos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Cleft lip with or without cleft palate (CL/P) occurs in approximately 1/500 to 1/1000 newborns and cleft palate (CP), etiologically distinct, in approximately 0,4/1000 newborns. They have a complex etiology, and the great majority of clefts appear to be isolated anomalies, in which have been observed a very important genetic component. However, in a significant number of cases, the individuals present congenital anomalies associated, of known etiology (monogenic syndromes or chromosomal aberrations), or without identified cause. Orofacial cleft can be part of the phenotype in individuals with different abnormalities in several chromosomes, including trissomies, translocations and inversions, duplications, deletions and microdeletions. The aims of this study were to identify chromosome aberrations in CL/P, CP and rare facial cleft individuals, and informative cases for specific studies, as well. The sample was constituted of 41 subjects with cleft lip with or without cleft palate (CL/P), cleft palate (CP) and rare facial cleft. The cases were referred to a clinical genetic service for diagnosis and genetic counseling at a non specialized on craniofacial anomalies hospital between 2001 and 2006. The patients were evaluated by clinical geneticist and divided clinically in five different groups: individuals with multiple congenital anomalies, syndromic cases, sequences, secondary dismorphisms and isolated cases. Chromosomal analysis was carried out on lymphocytes cultured from peripheral blood, with G banding at a resolution of 500 to 600 bands. We found informative chromosome abnormalities in 11 patients, ten in individuals with multiple congenital anomalies and one in an individual with an isolated CL/P. We detected informative chromosome abnormalities in three individuals with CL/P, five individuals with CP and two individuals with rare facial cleft. The main chromosome abnormality detected was the supernumerary chromosome marker in low mosaicism (6/11). To better elucidate these cases will be necessary to perform conventional and molecular cytogenetic complementary studies. It was carried out the complementary study in a case of 18q deletion syndrome, refining the breakpoints and the stretch of the deleted region in two patients, using DNA polymorphic markers. These results reflect the reality of a genetic service of a tertiary hospital not specialized, whose patient group is predominantly of cases associated with congenital anomalies. However, it was found an abnormal karyotype in a clinically isolated case. Cytogenetic studies in a large sample and different cleft populations, considering the same clinical classification adopted in this study, would better demonstrate the importance of chromosomal analysis in the routine of service of the different orofacial clefts

ASSUNTO(S)

fissura palatina cleft palate cromossome aberrations aberrações cromossomicas fenda labial cleft lip

ACESSO AO ARTIGO

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