Additional findings included cleft-lip and palate, a triangular shaped head and cupping of the left ear. Fetal weight was estimated to be less than the tenth percentile for gestational age. The lifespan of babies affected by this chromosome abnormality is severely shortened. The average length of survival of an infant with trisomy 13 is approximately 4 days.
Etiology is chromosomal nondisjunction during meiosis.
The pathology of trisomy 13 syndrome. Wladimiroff, JW et al. Sonographically Determined Anomalies and Outcome in 170 Chromosomally Abnormal Fetuses.