Trisomy 18 Essay Example | Topics and Well Written Essays - 1750 words

Trisomy 18 - Essay Example The incidence of the condition during first trimester scanning is 1 in 400 (Chen, Emedicine). There is a strong female predominance with more than 80 percent of the detected cases being females. The condition does not have any racial predilection(Chen, Emedicine). 95 percent of pregnancies with trisomy 18 embryos spontaneously abort. Of the remaining which are born, only 5-10 percent survive beyond the first year of life. Thus, the mortality rate of this condition is very high. The mortality rate is because of the severely malformed organs like the heart, kidney and the brain, feeding problems, high rates of infection and breathing difficulties. The longest survival reported for this condition so far is 27 years (Chen, Emedicine). The condition is detectable in the prenatal period. Some of the features which point to the possibility of trisomy 18 are maternal polyhydramnios or oligohydramnios, very small placenta, single umbilical artery, intrauterine growth retardation, fetal distress, defective fetal reflexes and decreased fetal activity. In the postnatal period, the clinical condition is obvious because of the array of clinical features. The new born usually has generalized hypotonia, apnea, jitteriness and seizures. The child will have marked failure to thrive, recurrent apnoiec episodes and poor feeding (Chen, Emedicine). On examination several organ defects will be obvious. The child may have defects of the skull manifesting as microcephaly, wide fontanellaes, prominent occiput, elongated skull or even narrow bifrontal diameter. Facial deformities include microphthalmia, micrognathia, microstomia, short palpebral fissures, epicanthal folds, choanal atresia, periauricular tags, and narrow palatal arch. S evere skeletal deformities exist including growth retardation, radial hypoplasia, clenched hands, syndactyly, rocker bottom feet, narrow pelvis, talipes equinovarus, etc. Typical of the clenched fingers include "overlapping digits, with the second and