trisomy 18

trisomy 18,

a congenital condition caused by the presence of an extra chromosome 18, characterized by severe mental retardation and multiple deformities. Among the most common defects are scaphocephaly or other skull abnormalities; micrognathia; abnormal facies with low-set malformed ears and prominent occiput; cleft lip and palate; clenched fists with overlapping fingers, especially the index over the third finger; clubfeet; and syndactyly. Ventricular septal defect, patent ductus arteriosus, atrial septal defect, and renal anomalies are also common. The condition occurs in about 1 in 3000 births and predominantly in females, at a 3:1 sex ratio, and survival for more than a few months is rare. Also called Edwards' syndrome, trisomy E syndrome, trisomy 16-18.

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trisomy 18

Edwards syndrome A chromosome defect due to duplication of chromosome 18 Clinical Mental retardation, hypotonia, polyhydramnios, FTT, small placenta, low-birth-weight, micrognathia, ASD, VSD, PDA, horseshoe kidney, unilateral or double kidney, double ureter, inguinal or umbilical hernia, nail hypoplasia, cleft lip and palate, deformed skull, low-set malformed ears, short sternum, cryptorchidism Incidence 1:3-11,000 Prognosis Death usually by age 2