| Popis: |
Despite the frequency of trisomy 13, information regarding the natural history is limited. The frequently cited pessimistic survival statistics are based on the large (over 200 cases) study of Magenis et al.which is now 30 years old. More recently a survey of parents belonging to the Support Organization for Trisomies (SOFT) provided more optimistic survival data as well as some information on growth, medical history, and recurrence risk in trisomy 13 (Baty et al 1994). Because these data were provided by parents who belong to a self-selected group, the possibility of ascertainment bias toward milder, longer surviving cases must be considered. We report our series of 18 unselected consecutive liveborn patients with trisomy 13 observed during the last 5 years. 10 patients died in the neonatal period, 1 died at 2.5 weeks, 1 died at 2.5 years, and the remainder were last known to be alive at ages of 1 mo, 3mo, 6mo, 1 yr, and 2 yrs (2 patients). Therefore the probability of survival was 47% at 1 week, 41% at one month, 33% at 6 mo, and 29% at 1 yr. Although the percentage of neonatal deaths is greater, the survival at later ages is comparable to the SOFT data. Complex congenital heart disease was the strongest indicator of poor prognosis, found in 7/9 patients who died neonatally and in none of those surviving more than 1 month. Other indicators of severe prognosis were gestation 36 weeks, not ventilator dependent, and do not have complex congenital heart disease or severe CNS lesions have a significantly better prognosis (5/6 survived > 3months). There were no familial recurrences of trisomy 13 in our study, but one family had a previous child with trisomy 18. The mothers of our patients had a total of 32 previous pregnancies resulting in 19 livebirths (including the trisomy 18) and 13 miscarriages (no reported theraputic abortions). These data are comparable to the SOFT data which included 40 previous pregnancies with 9 miscarriages and one family with a previous trisomy 18 conception. Combining these data yields a risk of 31% for miscarriage and 3% for autosomal trisomy in previous pregnancies. The recurrence risk for autosomal trisomy may be greater than previously suggested. |
