Retrospective cohort of trisomy 18 (Edwards syndrome) in southern Brazil

Comprehensive phenotyping of fetuses with trisomy 18: a perinatal center experience

Trisomy 18 is the second most common aneuploidy after trisomy 21. It presents with varying degrees of heterogeneous clinical phenotypes involving multiple organ systems, with a high mortality rate. Clinical assessment of fetal trisomy 18 is always challenging. In this study, we describe the phenotypes of the fetuses with trisomy 18 from a perinatal cohort. We reviewed fetuses with trisomy 18 in referrals for perinatal autopsy over the period of 15 years. A detailed phenotyping of the fetuses with trisomy 18 was executed by perinatal autopsy. Appropriate fetal tissues were obtained to perform genomic testing. We observed trisomy 18 in 16 fetuses (2%) in our cohort of 784 fetal/neonatal losses and a perinatal autopsy was performed on all of them. Abnormal facial profile was the most frequent anomaly (10/16, 62%) followed by anomalies of the extremities (9/16, 56%), and cardiac defects (6/16, 37%). We also observed esophageal atresia, diaphragmatic hernia, and neural tube defect. The study represents one of the largest cohorts of trisomy 18 from a perinatal center from a developing country and highlights the clinical heterogeneity attributed to trisomy 18. We also report a recurrence of trisomy 18 in a family.

The most relevant chromosomal abnormalities in the north of Rio Grande do Sul, Brazil: 26 years of cytogenetic analysis

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.