The incidence of Pätau syndrome is estimated at an average of 1:5,000 newborns. Free trisomy13 is detected in 75%, mosaic trisomy in 5%, and unbalanced translocation in 20%. The characteristic external malformations include a mostly bilateral cleft ligament, various eye defects (micro- or anophthalmia, coloboma), microcephaly, hexadactyly, ear dysplasia, scalp defects, and omphalocele. Organ malformations include heart defects, cystic kidneys, and CNS anomalies such as arhinecephaly or holoprosencephaly. Psychomotor development is severely impaired. About 50% of the patients die within the first month of life, more than 90% within the first year of life.
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