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Survival in trisomy 18
1Department of Pediatrics, University of Utah Health Sciences Center, Salt Lake City 84112.
Insights
Trisomy 18 (Edwards syndrome) survival rates are shorter than previously reported, with a median survival of 4 days. However, Utah data shows higher 6-month and 1-year survival compared to recent studies.
Area of Science:
- Genetics
- Pediatrics
- Prenatal Diagnosis
Background:
- Prenatal diagnosis of trisomy 18 is common, necessitating accurate prognostic information for families.
- Recent studies indicate significantly shorter survival for trisomy 18 than previously documented.
- Understanding current survival trends is vital for informed decision-making regarding delivery management.
Purpose of the Study:
- To investigate trisomy 18 survival rates.
- To compare current survival data with historical and recent findings.
- To provide updated prognostic information for trisomy 18.
Main Methods:
- Analysis of chromosome laboratory records for trisomy 18 diagnoses in Utah (1979-1988).
- Utilized death certificates and hospital records to determine survival outcomes.
- Calculated prevalence, median survival, and survival rates at 1 week, 6 months, and 1 year.
Main Results:
- Identified 64 liveborn cases of trisomy 18, with a prevalence of 1/6071.
- Median survival was 4 days; 45% survived 1 week, aligning with recent studies.
- Utah data showed higher survival at 6 months (9%) and 1 year (5%) compared to other recent studies (3% and 0%, respectively).
Conclusions:
- Trisomy 18 survival appears shorter than in earlier reports, likely influenced by earlier diagnosis.
- While short-term survival aligns with recent data, Utah's long-term survival rates at 6 months and 1 year are notably higher.
- Discrepancies in long-term survival may be attributed to variations in diagnostic timing and potentially small study numbers.
Abstract:
Prenatal diagnosis of trisomy 18 by amniocentesis in the latter half of pregnancy is now a common event. Accurate prognostic information is crucial for families making decisions about delivery management. Three recently published studies showed much shorter survival for trisomy 18 than was reported by earlier papers. For this reason, we studied trisomy 18 survival. We examined chromosome laboratory records to find all trisomy 18 diagnoses made in Utah between 1979 and 1988. Death certificates and hospital records were used to determine survival. We found 64 liveborn cases with trisomy 18 out of 388,563 total births over the 10-year period, a prevalence of 1/6071. Our results show a median survival of 4 days and a 1 week survival of 45%, similar to that reported in the 3 recent studies. However, we had a significantly greater survival at 6 months (9% in Utah versus 3% in Denmark) and 1 year (5% versus 0 in the 3 studies). In contrast to recent studies, earlier investigations showed 80% survival at 2 weeks and 8% at 1 year. It is not surprising that recent studies show shorter survival, since in the 1960s the diagnosis was typically not made until age 2 months. With prenatal and neonatal diagnosis many cases which would have died prior to detection in earlier times are now diagnosed. The longer survival discrepancies are more difficult to explain, but may simply be due to small numbers.