ABSTRACT
From 1992 to 2018, cytogenetic analyses were successfully performed to explore the chromosomal abnormalities of 729 patients, who utilised a pioneering counselling service in the city of Passo Fundo in the northern part of the Brazilian state of Rio Grande do Sul. This city is characterised by a large conglomerate of private and public hospitals. A classical cytogenetic analysis and G-banding were performed using the patient samples. Although normal karyotypes were observed for 562 of the cases, 167 individuals evidenced chromosomal alterations. Among those, 110 exhibited numerical alterations (65.86%), 41 demonstrated structural modifications (24.55%) and 16 showed both numerical and structural chromosomal changes (9.58%). This study describes the diversity of the chromosomal alterations in this region, which have not been previously examined. After 26 years of study, the findings are discussed herein in a self-critical form.