2006-06-19-11Trisomy 13 © Elorza www.thefetus.net/
Carlos Elorza, MD, Carolina Zehnder Dendia, MD
*Chief of Ecography department, Hospital Italiano Garibaldi ** Member of Ecography department, Hospital Italiano Garibaldi, Rosario, Argentina
Definition: Chromosomal disorder characterized by the presence of an extra chromosome 13 or part of the long arm, presenting with congenital malformations.
Synonyms: Patau syndrome; D trisomy.
Case report: A 32-year-old woman, primigravida, underwent ultrasound examination at 29 weeks. The ultrasound findings were:
The delivery occurred at 35 weeks. The prenatal findings were confirmed. The newborn underwent a genetic study confirming trisomy 13 (47, +13). Forty-eight hours after delivery, the infant died.
Note the echogenic cardiac foci and cryptorchidism
Bilateral hydronephrosis. On the right image, note both kidneys and the bladder (close to the anterior abdominal wall)
Right image: Note both kidneys and the bladder in the middle
Postnatal view. Note the low-set and malformed ears and the microcephaly
Prevalence: 1:10,000 live births
Etiology: Autosomal trisomy (47, +13)
Pathogenesis: The pathogenesis is unknown.
Other chromosomic anomalies (trisomy 18 and 21)
Non-related chromosomic alterations renal dysplasia
Associated anomalies: capillary hemangioma, pseudostrabismus, cutis aplasia, ductal arterial permeability, microphthalmia, etc.
Prognosis: Most fetuses die while in-utero or during childhood. If they survive, these children may have severe development anomalies.
Recurrence risk: The recurrence risk varies according to the chromosomic defect and the maternal age. For trisomy 13, the risk of recurrence of trisomy 13 or any other clinically viable trisomy (trisomy 18 or 21) is of about 0.5% over the inherent risk to the maternal age.
Management: If trisomy 13 is diagnosed, the parents should be counseled about the poor prognosis. The interruption of the pregnancy may be offered. At birth the newborn with trisomy 13 are very irritable and generally present with hypotonia, hypertonia or myoclonia. Surgical procedures are usually delayed until the infant is several months old due to high perinatal mortality. Older children often develop scoliosis, visual alterations because of lack of retina development, and severe neurological and physical defects.