Chromosomal analyses in genetic counseling of patients with developmental and congenital abnormalities from Belém, Pará State, Brazil: a retrospective study of 17 years

Abstract

ABSTRACT OBJECTIVE: To present a retrospective study covering 17 years of referral of patients to a public clinical cytogenetic service in Belem, Para State, located in the Brazilian Amazon. MATERIALS AND METHODS: This study was based on a retrospective survey conducted from 1997 to 2014, considering registered chromosome G-banding results and relating them to information collected during patient evaluation. RESULTS: From a total of 1,580 patients, 730 (46.2%) had chromosomal abnormalities, of which 637 (87.3%) showed numerical alterations. Abnormalities involving autosomal chromosomes were more frequent, 524/730 (71.8%), while alterations in sex chromosomes comprised 28.2% (206). Down's syndrome was the most frequent, 424 (58.1%) of cases, followed by 175 (24.0%) cases of Turner's syndrome, and 25 (3.4%) of Klinefelter's syndrome. Patients with sex chromosome abnormalities were referred at a more advanced age when compared with those having autosomal chromosome abnormalities, with peaks around 11-15 years old (30.1% of cases) and 0-6 months old (40.5%), respectively. CONCLUSION: These findings are very similar to other studies and draw attention to public measures to improve both the quality with regard to diagnosis and the subsequent care of the patient. Keywords: Chromosome Disorders; Chromosome Banding; Congenital Abnormalities; Intellectual Disability; Cytogenetics